Playing with PSK31 earlier today, and after modifying my interface, ive realised that im badly over driving the transmitter at all but the lowest settings of the interface's level control. I seem to need a fair amount of initial attenuation in the tx audio path, if im to use the system without having to worry about the volume settings of the PC. To do this, I need to add another variable resistor, a preset pot, into the tx audio path. This will be set, with the level control in bypass and the output of the PC soundcard at maximum, to the point where the Tx power just stops getting any higher. Anything above this, and its over driving, and engaging the transmitters ALC very heavily. With this preset in place and set up, the level control should then act to set the effective transmit power without any distortion.
As soon as I can get the 1:1 transformers, I will build another interface unit, which will effectively be a 'universal' interface. This will have the same max drive and level controls as above, but also a volume control in the receive audio path. It will also use a tone operated PTT circuit, rather than the serial port driven PTT in the current interface. Control of the PTT will then be entirely by the datamode software sending a control tone at high level on the Right audio channel. To get the transformers I need a load of old modem cards! Ive put feelers out at work, im hoping someone in IT will dump some my way.
To try and get another audio channel available to dedicate to digimodes, I installed one of my old Soundblaster audio PCI cards. Windows took a look, and told me to naff off! No drivers available for it for Windows 7. So, ive decided to take a chance with an el-cheapo USB soundcard. For £1.50 if it doesnt work ive not lost out much. If it does work then all well and good.
The problems with the audio levels are annoying because it means I havent been able to play with my new PSK-20 transceiver yet. I have however, decided already that it needs some mods! Nothing drastic, but the addition of an on/off switch, and a Power LED, would seem prudent. Ive also found out about a simple Tuning indicator mod. It seems early versions of the PSK-20 (the ones that required serial port PTT lines) had a RF sniffer test point. This is missing on the later model I have, but consists of just a pair of 1N4148 diodes, a resistor and a capacitor. This then drives an LED and gives a visual indication of transmit status, and also of modulation and potential VSWR problems. I will add these, but I must take my time marking and drilling, as the case is very nice and I dont wish to spoil it.
Friday, 31 January 2014
Loosening my load
I was wondering why my little analogue multimeter wouldn't read any resistance values. It seems I'd forgotten to put a battery in it!
Well, I don't have any suitably rated 200 ohm resistors to make the load with, but I do have thousands of 1k 1/4w resistors. Now, 20 1k resistors in parallel gives exactly 50 ohms. It also, by lucky chance, gives a combined power rating of 5w. This is more than the meter is rated for, but that's no matter for the convenience.
The first difficulty then, was cutting the two holes needed in the tin. The BNC wasn't so hard, the step drill took care of the hole and the edge of the lid, and tin shears did the rest. The cutout for the meter was trickier. The mass of metal was removed by drilling numerous small holes and snipping it out, but then it was a case of slow, careful work with needle files.
A few test fittings of the meter showed up the tight spots, and soon a good fit was established
A great feature of working with tinplate is that you can solder direct to it. The first ten resistors were installed between a copper bus and the case, taking care to ensure they all fitted neatly in the space available without being too near the meter
The other side was then done, and before proceeding the load bank was tested to ensure correct resistance. It metered out at 51 ohm, which is pretty close for 5% tolerance resistors. The remaining components installed point to point, with the electrolytic capacitor doing double duty as a stand-off post!
On test, I can prove that the circuit works. However, my test method was to feed the PSK31 idle signal from the DX-70TH into it, via the SWR bridge in the ATU. At FSD, the ATU's meter was showing just 1W. FSD on this should be 2W. I suspect the problem is the inaccuracy of the ATU's meter at these low powers. I'll have to find someone with a calibrated power source to calibrate it against. I could try it against a VHF handheld, calibrated to 2W against my Marconi 2955, but im not sure how well it would perform at VHF. Apart from calibration, and a new meter scale, the only thing left to do with this project is label it up and put some rubber feet on it!
Just prior to moving onto my next task, the modification of the digimode interface, I was looking at the antenna that came with the little DVB-T2 USB stick. Now, no matter what I do I cant get a peep out of the stick, that might be due to the antenna, but i'm really not too fussed. The antenna is a little one inch magmount. I started wondering if its fitting was the same as the little dual band magmount that a certain Richard had conned me into swapping a decent sized magmount base for! And indeed it is! So, Ive swapped the elements over. All that's needed now is to change the little plug on it for a BNC, and it should be a usable little dual band 2m/70cm magmount.
Modifying the digimode interface proved a bit tricky, simply due to the amount of wiring in there. Unfortunately, once modified, I found that the radio would complain bitterly in bypass mode even with very little volume set on the PC. Even in 'level control' mode, ie with the internal level pot switched in, only the first 5-10% of the track has any affect, above that the radio complains about being over driven. That 5-10% is from the 'cold' end, and so represents most of the resistance in series. The pot is a 10k, which should be fine, but I have a feeling its track may be damaged, either that or I need a log taper pot in there. It also seems that the speaker out levels of the PC are way too strong even when turned right down. So I don't yet dare feed the PC audio to the PSK-20 to test it. I think that might have to await its own interface unit. I have a 22k log pot I could try, but im inclined to go higher, perhaps 100k
Anyway, its raining now, and a bit cold for being in the workshop. So radio work has been put on hold in favour of model painting and tea drinking. I might revisit the power meter later if the rain stops, and try a few tricks with it. I also intend seeing if I can add another soundcard into this computer, so I can dedicate the settings to feeding the radios, that means a trip into the loft to dismantle the old PC.
Well, I don't have any suitably rated 200 ohm resistors to make the load with, but I do have thousands of 1k 1/4w resistors. Now, 20 1k resistors in parallel gives exactly 50 ohms. It also, by lucky chance, gives a combined power rating of 5w. This is more than the meter is rated for, but that's no matter for the convenience.
The first difficulty then, was cutting the two holes needed in the tin. The BNC wasn't so hard, the step drill took care of the hole and the edge of the lid, and tin shears did the rest. The cutout for the meter was trickier. The mass of metal was removed by drilling numerous small holes and snipping it out, but then it was a case of slow, careful work with needle files.
A few test fittings of the meter showed up the tight spots, and soon a good fit was established
A great feature of working with tinplate is that you can solder direct to it. The first ten resistors were installed between a copper bus and the case, taking care to ensure they all fitted neatly in the space available without being too near the meter
The other side was then done, and before proceeding the load bank was tested to ensure correct resistance. It metered out at 51 ohm, which is pretty close for 5% tolerance resistors. The remaining components installed point to point, with the electrolytic capacitor doing double duty as a stand-off post!
On test, I can prove that the circuit works. However, my test method was to feed the PSK31 idle signal from the DX-70TH into it, via the SWR bridge in the ATU. At FSD, the ATU's meter was showing just 1W. FSD on this should be 2W. I suspect the problem is the inaccuracy of the ATU's meter at these low powers. I'll have to find someone with a calibrated power source to calibrate it against. I could try it against a VHF handheld, calibrated to 2W against my Marconi 2955, but im not sure how well it would perform at VHF. Apart from calibration, and a new meter scale, the only thing left to do with this project is label it up and put some rubber feet on it!
Just prior to moving onto my next task, the modification of the digimode interface, I was looking at the antenna that came with the little DVB-T2 USB stick. Now, no matter what I do I cant get a peep out of the stick, that might be due to the antenna, but i'm really not too fussed. The antenna is a little one inch magmount. I started wondering if its fitting was the same as the little dual band magmount that a certain Richard had conned me into swapping a decent sized magmount base for! And indeed it is! So, Ive swapped the elements over. All that's needed now is to change the little plug on it for a BNC, and it should be a usable little dual band 2m/70cm magmount.
Modifying the digimode interface proved a bit tricky, simply due to the amount of wiring in there. Unfortunately, once modified, I found that the radio would complain bitterly in bypass mode even with very little volume set on the PC. Even in 'level control' mode, ie with the internal level pot switched in, only the first 5-10% of the track has any affect, above that the radio complains about being over driven. That 5-10% is from the 'cold' end, and so represents most of the resistance in series. The pot is a 10k, which should be fine, but I have a feeling its track may be damaged, either that or I need a log taper pot in there. It also seems that the speaker out levels of the PC are way too strong even when turned right down. So I don't yet dare feed the PC audio to the PSK-20 to test it. I think that might have to await its own interface unit. I have a 22k log pot I could try, but im inclined to go higher, perhaps 100k
Anyway, its raining now, and a bit cold for being in the workshop. So radio work has been put on hold in favour of model painting and tea drinking. I might revisit the power meter later if the rain stops, and try a few tricks with it. I also intend seeing if I can add another soundcard into this computer, so I can dedicate the settings to feeding the radios, that means a trip into the loft to dismantle the old PC.
Thursday, 30 January 2014
The power of menthol
How powerful is menthol? In this case, up to 2W!
Yet another empty Altoids 'curiously strong mints' tin is due to be pressed into service tomorrow, this time to accommodate a 2W QRP power meter. Using the little 250uA movement I have, it should read from about 100mW up to 2W reasonably well.
Based on a simple design by AA5TB, Ive had to recalculate the series resistor value, which meant quite a lot of first principle maths. The end result of all the calculations was a resistor value of 53.7k. Not a preferred value in anyone's book! Rounding up to 54k, also not a preferred value, I saw that the nearest available resistors were quite a ways out. So, my design will have a pair in series, a 39k and a 15k. The trick now though will be finding some suitably power rated 200 ohm resistors to build the dummy load section.
For tonight, there's little I can do, apart from paint the Altoids tin ready. This is also having a nice shade of grey, but this time in Revell Enamel.
I'll also be adding a bypass switch to my digimodes interface. This is a simple beast, a pair of 1:1 600 ohm isolation transformers for the audio and an opto-isolator for the PTT control
It is however, very customised for my station. The socket on the front is for the Alinco DX-70's microphone, a DIN socket on the back then connects via a patch lead to the Alinco's microphone socket. This means I can select between mic and audio in/out lines, the front panel switch being for that purpose. The PTT control is via RS232, but this is also fed out the back via a 3.5mm stereo jack to the CAT interface for my FRG-100 receiver, allowing computer control of that as well. The bypass switch I wil fit tomorrow will allow switching out the level control pot.
Yet another empty Altoids 'curiously strong mints' tin is due to be pressed into service tomorrow, this time to accommodate a 2W QRP power meter. Using the little 250uA movement I have, it should read from about 100mW up to 2W reasonably well.
Based on a simple design by AA5TB, Ive had to recalculate the series resistor value, which meant quite a lot of first principle maths. The end result of all the calculations was a resistor value of 53.7k. Not a preferred value in anyone's book! Rounding up to 54k, also not a preferred value, I saw that the nearest available resistors were quite a ways out. So, my design will have a pair in series, a 39k and a 15k. The trick now though will be finding some suitably power rated 200 ohm resistors to build the dummy load section.
For tonight, there's little I can do, apart from paint the Altoids tin ready. This is also having a nice shade of grey, but this time in Revell Enamel.
I'll also be adding a bypass switch to my digimodes interface. This is a simple beast, a pair of 1:1 600 ohm isolation transformers for the audio and an opto-isolator for the PTT control
It is however, very customised for my station. The socket on the front is for the Alinco DX-70's microphone, a DIN socket on the back then connects via a patch lead to the Alinco's microphone socket. This means I can select between mic and audio in/out lines, the front panel switch being for that purpose. The PTT control is via RS232, but this is also fed out the back via a 3.5mm stereo jack to the CAT interface for my FRG-100 receiver, allowing computer control of that as well. The bypass switch I wil fit tomorrow will allow switching out the level control pot.
10m Wispy Receive chain started
This part of the wispy is pretty low on component count, which is just as well as I only have about four square inches of space to build it in.
Starting with the grounded gate RF amplifier and the Polyakov mixer, straight away I get hit with a small problem. The design specifies an MPF102 JFET, but I dont have any. I do have plenty of J310s and 2N3819s. Although I have asked for a confidence check on my decision from the members of G-QRP club, I went ahead anyway and selected a J310. Both the MPF102 and the J310 are listed as VHF devices, so hopefully all will be well here.
The RF amp and mixer occupy the left hand side of the receive chain space of the board. This allows the LO signal to be fed direct from the oscillator without any extended wiring. It does mean however that the antenna RF signal to the receiver now has to come a bit further! The toroid on the lower left and the trimmer cap on the right (next to the LPF toroid) form the front end filter, and somewhere along that line a pair of back to back silicon diodes perform the job of antenna switching. These will probably be located close to the trimmer cap.
The next trick is to turn my brain upside down, in order to be able to think my way around building the Rx audio pre-amp and power amps with their power rails to the lower edge of the PCB and their grounds towards the middle!.
I have stopped work for today though, as its getting bloody cold!
I have also realised that I really need a way to measure RF power down to a few tens of mW, and up to a watt or two, for testing these projects. So a QRP power meter looks to be on the bench for tomorrow, so long as I can find a suitable design. Yes, I know Sprat is full of them, but the only meter I have spare thats not the size of something you'd expect to see in a 1920s Frankenstein film, is a little 250uA movement, so I need a circuit that will work with that.
Starting with the grounded gate RF amplifier and the Polyakov mixer, straight away I get hit with a small problem. The design specifies an MPF102 JFET, but I dont have any. I do have plenty of J310s and 2N3819s. Although I have asked for a confidence check on my decision from the members of G-QRP club, I went ahead anyway and selected a J310. Both the MPF102 and the J310 are listed as VHF devices, so hopefully all will be well here.
The RF amp and mixer occupy the left hand side of the receive chain space of the board. This allows the LO signal to be fed direct from the oscillator without any extended wiring. It does mean however that the antenna RF signal to the receiver now has to come a bit further! The toroid on the lower left and the trimmer cap on the right (next to the LPF toroid) form the front end filter, and somewhere along that line a pair of back to back silicon diodes perform the job of antenna switching. These will probably be located close to the trimmer cap.
The next trick is to turn my brain upside down, in order to be able to think my way around building the Rx audio pre-amp and power amps with their power rails to the lower edge of the PCB and their grounds towards the middle!.
I have stopped work for today though, as its getting bloody cold!
I have also realised that I really need a way to measure RF power down to a few tens of mW, and up to a watt or two, for testing these projects. So a QRP power meter looks to be on the bench for tomorrow, so long as I can find a suitable design. Yes, I know Sprat is full of them, but the only meter I have spare thats not the size of something you'd expect to see in a 1920s Frankenstein film, is a little 250uA movement, so I need a circuit that will work with that.
Soldering on!
With the sad demise of my long time trusty 18w Antex soldering iron, I had to quickly obtain another if I were to be able to carry on with my various radio projects. Since I mostly build 'dead bug' or 'Manhattan' style these days, often making the cabinet from the same PCB material soldered together, I opted to get the 25w Antex iron this time. Ordered on Amazon to take advantage of free postage, it came virtually next day!
I have to say, im not so keen on the new body shape of the iron, but its still ergonomic enough and works a treat. So, ive managed to complete the Two Tone test oscillator. It wasnt quite as simple as expected, as it turned out the salvaged phono socket i'd chosen didnt make contact with the plug pin! So, that was ripped out, and another salvaged connector, this time a BNC, installed in its place. Testing it on the now warmed up frequency counter (ive had the heater on for three hours as the workshop was freezing!), showed the low frequency oscillator running at 650Hz, and the high side at 1500Hz. Not exactly as i'd wanted, but not harmonically related, so ok for the proposed purpose.
Another bit of salvage, this time the knob, finished off the project apart from its aesthetics. So, since im painting a 1:72 model Vulcan at the moment, its getting a coat of Humbrol No. 164 Sea Grey acrylic!
I like to paint Altoids type tins when used for projects, as it makes it easier to put markings on them. I'd normally use enamel paint though, but the acrylic was out on the table already.
The oscillator has already had its first operational outing, driving the AF input of the 10m Wispy in its first test with a ground independent audio source. The results are promising - there seemed to be no RF output without modulation. A problem I have with this setup though is that my spectrum analyser cannot go below 1MHz bandwidth, which makes observing the DSB modulation with a pair of very narrow audio tones difficult. But from what I could make out, it seems to be ok.
The above shows the observed spectrum at the base of the driver transistor with the two-tone audio input. The picture below shows the 10m Wispy and the oscillator under test
As my test equipment and setup is not very sophisticated, I may still ship the Wispy to someone else with a better setup to have it tested and measured to see if all is really well. For instance, I cannot measure the very low Tx power at the moment, and am a little concerned that the 2nd harmonic isnt being attenuated sufficiently. In the meantime, I will start the build of the receiver section, presuming of course that the two MPF102 FETs I have in stock are working!
Another issue that I need to look into is the performance of my interface to the Alinco DX-70TH. This I built with a level control pot, but it seems to do some odd things! For instance, at certain settings for low Tx power, there is audio tone in the speaker? Odd. And at other settings, reducing the volume of the audio fed to it actually increases the Tx power! I suspect an odd ALC action going on here, so think I might remove the level control and rely on setting the computers audio output level to set the Tx power.
Paul EI5KI, has sent me his 20m PSK-20 from Small Wonder Labs. This nice looking kit should produce a couple of watts on 20m and will be used for simple demonstrations, and maybe to provide a digital QRP station for the CHOTA event. I will give it a try on air either tonight or tomorrow.
I have to say, im not so keen on the new body shape of the iron, but its still ergonomic enough and works a treat. So, ive managed to complete the Two Tone test oscillator. It wasnt quite as simple as expected, as it turned out the salvaged phono socket i'd chosen didnt make contact with the plug pin! So, that was ripped out, and another salvaged connector, this time a BNC, installed in its place. Testing it on the now warmed up frequency counter (ive had the heater on for three hours as the workshop was freezing!), showed the low frequency oscillator running at 650Hz, and the high side at 1500Hz. Not exactly as i'd wanted, but not harmonically related, so ok for the proposed purpose.
Another bit of salvage, this time the knob, finished off the project apart from its aesthetics. So, since im painting a 1:72 model Vulcan at the moment, its getting a coat of Humbrol No. 164 Sea Grey acrylic!
I like to paint Altoids type tins when used for projects, as it makes it easier to put markings on them. I'd normally use enamel paint though, but the acrylic was out on the table already.
The oscillator has already had its first operational outing, driving the AF input of the 10m Wispy in its first test with a ground independent audio source. The results are promising - there seemed to be no RF output without modulation. A problem I have with this setup though is that my spectrum analyser cannot go below 1MHz bandwidth, which makes observing the DSB modulation with a pair of very narrow audio tones difficult. But from what I could make out, it seems to be ok.
As my test equipment and setup is not very sophisticated, I may still ship the Wispy to someone else with a better setup to have it tested and measured to see if all is really well. For instance, I cannot measure the very low Tx power at the moment, and am a little concerned that the 2nd harmonic isnt being attenuated sufficiently. In the meantime, I will start the build of the receiver section, presuming of course that the two MPF102 FETs I have in stock are working!
Another issue that I need to look into is the performance of my interface to the Alinco DX-70TH. This I built with a level control pot, but it seems to do some odd things! For instance, at certain settings for low Tx power, there is audio tone in the speaker? Odd. And at other settings, reducing the volume of the audio fed to it actually increases the Tx power! I suspect an odd ALC action going on here, so think I might remove the level control and rely on setting the computers audio output level to set the Tx power.
Paul EI5KI, has sent me his 20m PSK-20 from Small Wonder Labs. This nice looking kit should produce a couple of watts on 20m and will be used for simple demonstrations, and maybe to provide a digital QRP station for the CHOTA event. I will give it a try on air either tonight or tomorrow.
Wednesday, 29 January 2014
Halifax ARC meeting and no luck with USB-SDR
I have to admit to being rather tired today. Yesterday, after a busy day all over the place picking up mast kit and firefighting equipment, all with a 'slightly' poorly Tom in tow, I drove over to Halifax to meet with the committee of Halifax Amateur Radio Club, who as it happens are not in Halifax but Mytholmroyd, even further from Selby!
Arriving at the club, once I finally found my way in, I found them in the middle of a lecture. One of the committee however spotted me and realised who I was, and so we went off to another room to talk CHOTA. At 'half time', and with a nice cup of coffee, I met with the whole committee, and we proceeded to discuss what their club could do at All Souls church. The result of the discussion was that the first major hurdle was overcome - enthusiasm! They had plenty! So it looks like a CHOTA station from All Souls, Halifax, on behalf of the Churches Conservation Trust, will go ahead as a sister station to mine at St. Marys.
There are some great opposites between the two churches. St Marys is a tiny chapel with absolutely no facilities, All Souls is a huge church, built by a famous architect, and has power etc on site. But, It has very little physical grounds and might be a challenge for antennas, whereas St Marys, provided the farmer lets me, has acres of field space for antennas!
One aspect discussed, was the possibility, that the trust are keen on, of a direct link-up on air between the two trust churches. Now, the terrain between them makes this a daunting prospect. On HF, the hills prevent contact by groundwave, and its likely were within skip zone for skywave, so HF is unlikely to work. VHF again is blocked by the hills, and would require the use of a repeater, something we cant set up as a temporary system. So, it seems impossible without a relay on a hilltop.
So, rather than admit defeat regarding a link-up, the Halifax club members proposed a very audacious method! Go even higher in frequency! A relay will still be required, but up in microwaves is feasable, and it seems they have the kit to do it. An end to end microwave relay link. Daring, to say the least, but certainly possible. It will need testing before the day, to prove it works of course.
But thats not all, as the TV infomercials are fond of saying. As were wanting to demonstrate the hobby in ways that are immediately impressive, a suggestion was made regarding transmission mode for the link. As we will have ample bandwidth to play with up on microwaves, we can use more bandwidth hungry modes. I will say no more at present. Its possible this blog will be read by someone from the trust, and I dont want to reveal the idea until its been tested and proved workable! If it works, it WILL be impressive, so I dont wish to get anyones hopes up (including mine!) in case its found to not be doable.
Another thing ive had a play with is trying to make this DVB-T2 USB stick I have work as an SDR (Software Defined Radio). It seems not all chipsets can be made to work, and I dont know the chipset of this device (I have asked the manufacturer), but I have tried to make it work and so far had no luck. The driver changer program says it cant do it as it doesnt have the privilages (im logged in as admin so it should) and so the SDRsharp program im using cant see it either. Hayho, it was free! Maybe I will find a way of getting it to work, maybe not, who knows. I'll have another go once ive found a bit more out about the device.
Arriving at the club, once I finally found my way in, I found them in the middle of a lecture. One of the committee however spotted me and realised who I was, and so we went off to another room to talk CHOTA. At 'half time', and with a nice cup of coffee, I met with the whole committee, and we proceeded to discuss what their club could do at All Souls church. The result of the discussion was that the first major hurdle was overcome - enthusiasm! They had plenty! So it looks like a CHOTA station from All Souls, Halifax, on behalf of the Churches Conservation Trust, will go ahead as a sister station to mine at St. Marys.
There are some great opposites between the two churches. St Marys is a tiny chapel with absolutely no facilities, All Souls is a huge church, built by a famous architect, and has power etc on site. But, It has very little physical grounds and might be a challenge for antennas, whereas St Marys, provided the farmer lets me, has acres of field space for antennas!
One aspect discussed, was the possibility, that the trust are keen on, of a direct link-up on air between the two trust churches. Now, the terrain between them makes this a daunting prospect. On HF, the hills prevent contact by groundwave, and its likely were within skip zone for skywave, so HF is unlikely to work. VHF again is blocked by the hills, and would require the use of a repeater, something we cant set up as a temporary system. So, it seems impossible without a relay on a hilltop.
So, rather than admit defeat regarding a link-up, the Halifax club members proposed a very audacious method! Go even higher in frequency! A relay will still be required, but up in microwaves is feasable, and it seems they have the kit to do it. An end to end microwave relay link. Daring, to say the least, but certainly possible. It will need testing before the day, to prove it works of course.
But thats not all, as the TV infomercials are fond of saying. As were wanting to demonstrate the hobby in ways that are immediately impressive, a suggestion was made regarding transmission mode for the link. As we will have ample bandwidth to play with up on microwaves, we can use more bandwidth hungry modes. I will say no more at present. Its possible this blog will be read by someone from the trust, and I dont want to reveal the idea until its been tested and proved workable! If it works, it WILL be impressive, so I dont wish to get anyones hopes up (including mine!) in case its found to not be doable.
Another thing ive had a play with is trying to make this DVB-T2 USB stick I have work as an SDR (Software Defined Radio). It seems not all chipsets can be made to work, and I dont know the chipset of this device (I have asked the manufacturer), but I have tried to make it work and so far had no luck. The driver changer program says it cant do it as it doesnt have the privilages (im logged in as admin so it should) and so the SDRsharp program im using cant see it either. Hayho, it was free! Maybe I will find a way of getting it to work, maybe not, who knows. I'll have another go once ive found a bit more out about the device.
Monday, 27 January 2014
Making with MeSquares
Having been directed to come directly home after work, instead of getting my few jobs done, because Tom wasnt feeling too good, I decided i'd get the two-tone generator built. To accomplish this I decided to use some of QRPme's 'MeSquares', these are 5mm pre-etched and tinned little squares of PCB material, which are superglued down to a larger piece of plain PCB in Manhattan Island style construction. My board was cut to fit into an Altoids tin, along with a PP3 battery
I slightly mucked up my parts layout, which resulted in a more 'circular' arrangement of the 10nF capacitors, but both oscillators did work first time. Although when measured on my frequency counter the actual frequencies were a bit off what I wanted. I changed the 3k3 resistors in one side for 2k7's to change the frequency a little
Once tested, Installation into the Altoids tin began. I didnt bother seriously measuring things here so its all a bit of a squeeze, and the holes are rather rough. A phono socket was selected for the output. Both the phono and the level control pot will need gluing in place as they were originally PCB mount types. A bit of foam or velcro will be needed to keep the battery in place.
Whilst trying to get the LED into its bezel, there was an immense sound of jet engines, a rush outside revealed the culprit - a Typhoon (or possibly an F18?), a scan of the UHF airband, hoping to turn up an active air defence exercise, failed to do so, but instead picked up, albeit rather weakly, a training sortie by the Red Arrows!
Rather unfortunately though, as I was soldering the power wiring, I found the solder wouldnt melt. My soldering iron element has failed! To be fair that 18w Antex iron has served me very well, ive had it for about 20years! A replacement is on order, this time a 25w iron. I could possibly complete this job with my 40w iron, but its an el-cheapo and suited more to plugs and cable than component level work.
All the while, ive had the DX-70 sat on 10m PSK-31. 10m looks to be rather dead today, although for a brief moment part of a QSO was decoded that clearly hinted at an Isreali origin.
I slightly mucked up my parts layout, which resulted in a more 'circular' arrangement of the 10nF capacitors, but both oscillators did work first time. Although when measured on my frequency counter the actual frequencies were a bit off what I wanted. I changed the 3k3 resistors in one side for 2k7's to change the frequency a little
Once tested, Installation into the Altoids tin began. I didnt bother seriously measuring things here so its all a bit of a squeeze, and the holes are rather rough. A phono socket was selected for the output. Both the phono and the level control pot will need gluing in place as they were originally PCB mount types. A bit of foam or velcro will be needed to keep the battery in place.
Whilst trying to get the LED into its bezel, there was an immense sound of jet engines, a rush outside revealed the culprit - a Typhoon (or possibly an F18?), a scan of the UHF airband, hoping to turn up an active air defence exercise, failed to do so, but instead picked up, albeit rather weakly, a training sortie by the Red Arrows!
Rather unfortunately though, as I was soldering the power wiring, I found the solder wouldnt melt. My soldering iron element has failed! To be fair that 18w Antex iron has served me very well, ive had it for about 20years! A replacement is on order, this time a 25w iron. I could possibly complete this job with my 40w iron, but its an el-cheapo and suited more to plugs and cable than component level work.
All the while, ive had the DX-70 sat on 10m PSK-31. 10m looks to be rather dead today, although for a brief moment part of a QSO was decoded that clearly hinted at an Isreali origin.
Churches On The Air - September 13th 2014
Unsure as to whether the Doncaster Show will be held this year, I started looking for other special events I could run. One that caught my attention was ChOTA - Churches On The Air. Organised by the World Association of Christian Radio Amateurs and Listeners (WACRAL) this encourages the running of special event stations from churches as a fund raising and hobby promoting activity.
WACRAL maintain a website, on which further details and lists of prospective stations may be found http://www.wacral.org/CHOTA.htm
My initial thought was Selby Abbey. But then I started to consider one of my favourite churches - St. Mary's Chapel, Lead, the 'Ramblers Church'. This is a lovely little church in the middle of a field on the edge of the historic Towton battlefield. It presents several interesting challenges for a radio station - it is tiny, so space is at a premium, and it has absolutely no utilities. No toilet, no water, no electricity!
The thought of operating from this wonderful location made the decision for me. If I can get permission, I will put on a station from St. Mary's.
St. Mary's is owned and maintained by the Churches Conservation Trust. This organisation looks after many old churches around the country, and their website http://www.visitchurches.org.uk/ has details of many to visit. After emailing them, I was invited to a meeting at St. Johns in Leeds to discuss the idea.
One difficulty when meeting people without a radio background, is explaining just what is intended, without leaving them dazed and confused. Now, I cant claim that I managed to explain everything properly, but I seem to have at least got the gist of the plan across, because the trust are very enthusiastic!
So with the trust on board, I can start planning the station. There are many problems that need solving, and many other people whose co-operation is essential. Not least the farmer who owns the field the church is in. The antenna systems will have to be put up in the field behind the church, and so the landowners permission is critical. Then comes power. Although battery is a last option, the ideal would be a small generator. This I hope to borrow from work, and will need to discuss this with management at some point. I then need assistance, not just volunteers for handling visitors, who will probably be supplied by the trust, but operators for the station. Then comes parking and access, facilities and refreshments, for this permission to utilise the Crooked Billet pub, next to the church, is likely to be key.
Once all this 'admin' is sorted, we then come to the nature of the station itself. I like to have a capable if small station. VHF, as ive found on other events, isnt very popular any more, and unless you have plenty of space and operators its not worth the effort of raising a heavy monopole antenna! Most CHOTA activity is on HF, generally 40m SSB, so this is what I intend to use as the primary station. Because of the need to keep the antenna clear of the public, I plan to use the 8m Larkspur mast to raise the feedpoint of a doublet, and then two 5.4m Clansman masts to raise the ends. A 135ft doublet, fed by 30ft of 300ohm ladderline and matched with my RT-11 remote auto ATU, will give me the frequency agility needed to allow a bit of DX as well.
As well as the primary station, I'd like to run a QRP demonstration station, to show how little expenditure it really takes to get into this hobby. Im not sure what to use yet, and it will be dependent on what QRP transceivers I can get, but I think a PSK-31 demo would be spot on. Even if I dont have an operator for it, it can sit quietly and automatically receiving and scrolling the QSOs across a laptop screen. An inverted V dipole off one of the Clansman masts will feed it. This may be on 80m using my MKARS-80 with suitable modification to its cooling, or perhaps 30m or 20m with a future QRP rig.
If I have the 10m Wispy working by then, The 10m fishing pole mast might also be put into service carrying my 10m J-pole antenna, and a WSPR beacon put on air alongside the station. Full operation will be possible if internet access can be arranged. If not, then Tx beaconing only will be utilised.
The trust are doing several WW1 commemorative events this year. It would be nice if the station could be tied into this, but the art of wireless communications was in its very infancy during WW1, and theres not much vintage equipment about. Theres also little space for an exhibition type station at St. Marys. However, another of the trusts churches is the considerably bigger All Souls in Halifax, which certainly has the space, close ties to the local museums, and an active radio club close by. I have contacted Halifax radio club and they are also keen on a CHOTA station, I will visit them this week to say hi and discuss possibilities. With a station at All Souls, we have the ability to do a direct link up between trust churches. Halifax club may be able to demonstrate WW2 vintage radios as part of their station.
The station is not until september, so there is lots of time to sort out the problems.
One aspect that has just occurred to me, is that we will be operating electrical equipment, ad-hoc, with potentially high voltages and at powers that may lead to elevated equipment temperatures, in a medieval building not ever intended to have such use. Likewise, we have potentially high discharge current batteries on site, and (hopefully) either LPG or petrol, and a hot generator. So, in addition to the normal HSE surveys and procedures that will be in place, I realise I will also have to ensure we bring with us any safety equipment thats needed. I carry first aid in the car anyway, but the types of equipment mean that a comprehensive emergency fire fighting capability would be prudent. For any risk from the generator, the dry powder extinguisher I carry in the car is adequate, but I would not want to use DP within the church, as it may have damaging consequences to building fabric. I will ensure we are equipped with CO2 for use on the station itself. Although, careful planning should mean that all this is just an exercise in good practice. I should have the CO2 extinguisher within the next week.
WACRAL maintain a website, on which further details and lists of prospective stations may be found http://www.wacral.org/CHOTA.htm
My initial thought was Selby Abbey. But then I started to consider one of my favourite churches - St. Mary's Chapel, Lead, the 'Ramblers Church'. This is a lovely little church in the middle of a field on the edge of the historic Towton battlefield. It presents several interesting challenges for a radio station - it is tiny, so space is at a premium, and it has absolutely no utilities. No toilet, no water, no electricity!
The thought of operating from this wonderful location made the decision for me. If I can get permission, I will put on a station from St. Mary's.
St. Mary's is owned and maintained by the Churches Conservation Trust. This organisation looks after many old churches around the country, and their website http://www.visitchurches.org.uk/ has details of many to visit. After emailing them, I was invited to a meeting at St. Johns in Leeds to discuss the idea.
One difficulty when meeting people without a radio background, is explaining just what is intended, without leaving them dazed and confused. Now, I cant claim that I managed to explain everything properly, but I seem to have at least got the gist of the plan across, because the trust are very enthusiastic!
So with the trust on board, I can start planning the station. There are many problems that need solving, and many other people whose co-operation is essential. Not least the farmer who owns the field the church is in. The antenna systems will have to be put up in the field behind the church, and so the landowners permission is critical. Then comes power. Although battery is a last option, the ideal would be a small generator. This I hope to borrow from work, and will need to discuss this with management at some point. I then need assistance, not just volunteers for handling visitors, who will probably be supplied by the trust, but operators for the station. Then comes parking and access, facilities and refreshments, for this permission to utilise the Crooked Billet pub, next to the church, is likely to be key.
Once all this 'admin' is sorted, we then come to the nature of the station itself. I like to have a capable if small station. VHF, as ive found on other events, isnt very popular any more, and unless you have plenty of space and operators its not worth the effort of raising a heavy monopole antenna! Most CHOTA activity is on HF, generally 40m SSB, so this is what I intend to use as the primary station. Because of the need to keep the antenna clear of the public, I plan to use the 8m Larkspur mast to raise the feedpoint of a doublet, and then two 5.4m Clansman masts to raise the ends. A 135ft doublet, fed by 30ft of 300ohm ladderline and matched with my RT-11 remote auto ATU, will give me the frequency agility needed to allow a bit of DX as well.
As well as the primary station, I'd like to run a QRP demonstration station, to show how little expenditure it really takes to get into this hobby. Im not sure what to use yet, and it will be dependent on what QRP transceivers I can get, but I think a PSK-31 demo would be spot on. Even if I dont have an operator for it, it can sit quietly and automatically receiving and scrolling the QSOs across a laptop screen. An inverted V dipole off one of the Clansman masts will feed it. This may be on 80m using my MKARS-80 with suitable modification to its cooling, or perhaps 30m or 20m with a future QRP rig.
If I have the 10m Wispy working by then, The 10m fishing pole mast might also be put into service carrying my 10m J-pole antenna, and a WSPR beacon put on air alongside the station. Full operation will be possible if internet access can be arranged. If not, then Tx beaconing only will be utilised.
The trust are doing several WW1 commemorative events this year. It would be nice if the station could be tied into this, but the art of wireless communications was in its very infancy during WW1, and theres not much vintage equipment about. Theres also little space for an exhibition type station at St. Marys. However, another of the trusts churches is the considerably bigger All Souls in Halifax, which certainly has the space, close ties to the local museums, and an active radio club close by. I have contacted Halifax radio club and they are also keen on a CHOTA station, I will visit them this week to say hi and discuss possibilities. With a station at All Souls, we have the ability to do a direct link up between trust churches. Halifax club may be able to demonstrate WW2 vintage radios as part of their station.
The station is not until september, so there is lots of time to sort out the problems.
One aspect that has just occurred to me, is that we will be operating electrical equipment, ad-hoc, with potentially high voltages and at powers that may lead to elevated equipment temperatures, in a medieval building not ever intended to have such use. Likewise, we have potentially high discharge current batteries on site, and (hopefully) either LPG or petrol, and a hot generator. So, in addition to the normal HSE surveys and procedures that will be in place, I realise I will also have to ensure we bring with us any safety equipment thats needed. I carry first aid in the car anyway, but the types of equipment mean that a comprehensive emergency fire fighting capability would be prudent. For any risk from the generator, the dry powder extinguisher I carry in the car is adequate, but I would not want to use DP within the church, as it may have damaging consequences to building fabric. I will ensure we are equipped with CO2 for use on the station itself. Although, careful planning should mean that all this is just an exercise in good practice. I should have the CO2 extinguisher within the next week.
Where It All Began, Pt 2
Second part of my inane ramblings about how I got into this hobby,
We start here with the young me making his way across the fields between my village and Erics, past the new Tescos (as was then). Very nervous, I arrived at Erics house and was shown into his shack. Well, this was the under stairs cupboard converted, and I had never seen so much radio kit! How the heck we fitted in their I dont know. In the dim light of the radios displays, and with the undecipherable sounds of HF, I was captivated.
John Dennis arrived, and I was bundled into the rear of a Volvo estate. A few minutes later, after Johns customary blind call on 2m FM of 'At the flats, Bob', we arrived in Balby at the home of Bob Honor. With Bob collected it was on to Harrop Hall in Mexborough, home of Mexborough and District Amateur Radio Society.
Harrop hall is a small square brick hall on a rather steep hill. It was here that I was induced onto the then City and Guilds Radio Amateurs Examination course, taught by Eric Rogers. I was certainly one of the youngest in the class. Back then, there were two UK classes of amateur license, A and B. A pair of passes or better in the RAE would give you a class B license, allowing up to 400W of transmit power, but restricted to the bands above 50MHz. In order to get a class A and move down to shortwave (HF), you had to pass a 12 words per minute Morse code test. Over the coming weeks, Eric taught us all about radio and electronics. I would learn about oscillators, amplifiers, antennas, propagation, modes and operating techniques.
Halfway through the evening, we stopped for tea and biscuits, prepared then, and indeed now, by Peter Myers. I became an established tea drinker, something that was thoroughly reinforced a few years later in the TA! Downstairs at the club, was the club shack. There I learnt more operating skills, and listened to the radios.
As the course progressed, I saved enough money to purchase my first radio, a Kenpro KT-22EE 2m FM handheld. This beast was a copy of an older Icom model, and its frequency was set by thumbwheel switches. By modern standards it was huge, but it worked well for me, until a few years later when it was nicked off my belt in Doncaster market!
I took the two exam papers at Mexborough comprehensive school. After a nerve jangling wait of several weeks I received my pass slips, showing I had earned Merit scores on both papers. I sent off my license application to the Radiocommunications Agency, with a cheque to Post Office Counters, and received back my license and allocated callsign - G7MRV.
I started to operate on-air. The first few calls are the most difficult, but I was soon active regularly. I built a 'slim-jim' antenna for my handheld, made from wire mounted on stiff cardboard, and wedged stood up on my desk. This worked well but had a habit of folding over and resting the high voltage sections on my bare arm! I progressed to a 25w Icom IC-229E mobile rig and a 'Sams Special' ex-PMR vertical antenna. I began making far reaching contacts, including when the conditions were right, across into Belgium and Denmark. It was then I found my love of working special event stations.
Soon, I was operating on club special event stations and field days. I manned stations on behalf of the scouts for Jamboree on the Air, and the guides for Thinking Day On the Air. I manned the Pilgrim Fathers station, taking the overnight shift with only one young lady for company, at Austerfield. It was during that operation that my lack of HF knowledge caused me to miss a chance to work JY1 - The King of Jordan! But my love of special event stations was ingrained by then.
We start here with the young me making his way across the fields between my village and Erics, past the new Tescos (as was then). Very nervous, I arrived at Erics house and was shown into his shack. Well, this was the under stairs cupboard converted, and I had never seen so much radio kit! How the heck we fitted in their I dont know. In the dim light of the radios displays, and with the undecipherable sounds of HF, I was captivated.
John Dennis arrived, and I was bundled into the rear of a Volvo estate. A few minutes later, after Johns customary blind call on 2m FM of 'At the flats, Bob', we arrived in Balby at the home of Bob Honor. With Bob collected it was on to Harrop Hall in Mexborough, home of Mexborough and District Amateur Radio Society.
Harrop hall is a small square brick hall on a rather steep hill. It was here that I was induced onto the then City and Guilds Radio Amateurs Examination course, taught by Eric Rogers. I was certainly one of the youngest in the class. Back then, there were two UK classes of amateur license, A and B. A pair of passes or better in the RAE would give you a class B license, allowing up to 400W of transmit power, but restricted to the bands above 50MHz. In order to get a class A and move down to shortwave (HF), you had to pass a 12 words per minute Morse code test. Over the coming weeks, Eric taught us all about radio and electronics. I would learn about oscillators, amplifiers, antennas, propagation, modes and operating techniques.
Halfway through the evening, we stopped for tea and biscuits, prepared then, and indeed now, by Peter Myers. I became an established tea drinker, something that was thoroughly reinforced a few years later in the TA! Downstairs at the club, was the club shack. There I learnt more operating skills, and listened to the radios.
As the course progressed, I saved enough money to purchase my first radio, a Kenpro KT-22EE 2m FM handheld. This beast was a copy of an older Icom model, and its frequency was set by thumbwheel switches. By modern standards it was huge, but it worked well for me, until a few years later when it was nicked off my belt in Doncaster market!
I took the two exam papers at Mexborough comprehensive school. After a nerve jangling wait of several weeks I received my pass slips, showing I had earned Merit scores on both papers. I sent off my license application to the Radiocommunications Agency, with a cheque to Post Office Counters, and received back my license and allocated callsign - G7MRV.
I started to operate on-air. The first few calls are the most difficult, but I was soon active regularly. I built a 'slim-jim' antenna for my handheld, made from wire mounted on stiff cardboard, and wedged stood up on my desk. This worked well but had a habit of folding over and resting the high voltage sections on my bare arm! I progressed to a 25w Icom IC-229E mobile rig and a 'Sams Special' ex-PMR vertical antenna. I began making far reaching contacts, including when the conditions were right, across into Belgium and Denmark. It was then I found my love of working special event stations.
Soon, I was operating on club special event stations and field days. I manned stations on behalf of the scouts for Jamboree on the Air, and the guides for Thinking Day On the Air. I manned the Pilgrim Fathers station, taking the overnight shift with only one young lady for company, at Austerfield. It was during that operation that my lack of HF knowledge caused me to miss a chance to work JY1 - The King of Jordan! But my love of special event stations was ingrained by then.
Sunday, 26 January 2014
First delve into Digimodes
Oh, alright then, its not quite the first time! Yes, way back in the '90s I played 2m Packet for a bit, and more recently a bit of WSPR from the main station, and I am working on the WSPR 10m transceiver for demo purposes. And yes, I have spent a lot of time decoding utility transmissions in FAX, RTTY etc. But I refer here to my first attempts at live, 2-way QSOs in the interesting world of 31 baud Binary Phase Shift Keying.
BPSK-31, or simply PSK-31 as its usually known, is something ive recently begun playing with. I have FLDIGI software installed on my PC, and the necessary PTT and audio lines to the Alinco DX-70TH already in place. So, after monitoring received signals for a while, I tuned the rig up on 80m, set it to low power on USB, and into test load sent it a continuous alignment tone. My interface unit allows me to adjust the audio drive level, which I did to give me a 5w output signal, hopefully nice and splatter and IMD free. I then switched back to antenna, and started to climb the learning curve...
The biggest trouble with learning this mode, is learning the software! Yes, its a Keyboard to Keyboard mode, so in theory I just have to type the message, but that's remarkably tedious when you have to type callsigns etc. So I started to explore the software's Macro buttons, which do all that tedious stuff for you (in fact, it can do everything for you!) It seems the trick is to use the very clever logging features of the software. As a contact comes in, when the callsign is displayed, you click on it, and it goes into the logs 'callsign' box, all well and good. Do that for name and location also. And then, when the macro button is pressed, the software auto populates these details in your transmission! Clever stuff. The only bit I haven't worked out how to do is the signal report, I'm still doing that on the keyboard.
Another smashing feature I discovered of this program is its ability to simultaneously decode all transmissions within band in the selected mode, display them live, and search them for a key phrase, such as 'CQ', highlighting when it spots matching transmissions. All you do then is click it, and your tuned and decoding that transmission ready to reply!
First few goes with this then, once set up, I started to reply to CQs, and was very pleased to be answered and make the contact. Tally so far is just a few inter-European QSOs, France, Spain, Germany, Poland. But as a first trial at just 5w (the power of my cars brake light!) its very encouraging. I still haven't fully mastered the macros yet, so don't always get it exactly right, but I'm sure with time that will come.
I want now to get or build a low cost, QRP PSK transceiver, for demo use, to show just how accessible the hobby is. I'm looking for a 20m version of the Warbler-80, which is very simple, but does use specialist crystals. I'd very much like to build a PSK-20 from small wonder labs, but they are now closed as the proprietor has retired. However I have been offered one complete, if its a sensible price I may go for it.
PSK-31 seems to be ideal demo material. Simple kit, low cost, and can be run from laptops, tablets etc. It should appeal to prospective, tech savvy youngsters. It also has the advantage of low power operation, and for those who need to keep quiet, can be done with no sound at all! Ideal for late night operating.
BPSK-31, or simply PSK-31 as its usually known, is something ive recently begun playing with. I have FLDIGI software installed on my PC, and the necessary PTT and audio lines to the Alinco DX-70TH already in place. So, after monitoring received signals for a while, I tuned the rig up on 80m, set it to low power on USB, and into test load sent it a continuous alignment tone. My interface unit allows me to adjust the audio drive level, which I did to give me a 5w output signal, hopefully nice and splatter and IMD free. I then switched back to antenna, and started to climb the learning curve...
The biggest trouble with learning this mode, is learning the software! Yes, its a Keyboard to Keyboard mode, so in theory I just have to type the message, but that's remarkably tedious when you have to type callsigns etc. So I started to explore the software's Macro buttons, which do all that tedious stuff for you (in fact, it can do everything for you!) It seems the trick is to use the very clever logging features of the software. As a contact comes in, when the callsign is displayed, you click on it, and it goes into the logs 'callsign' box, all well and good. Do that for name and location also. And then, when the macro button is pressed, the software auto populates these details in your transmission! Clever stuff. The only bit I haven't worked out how to do is the signal report, I'm still doing that on the keyboard.
Another smashing feature I discovered of this program is its ability to simultaneously decode all transmissions within band in the selected mode, display them live, and search them for a key phrase, such as 'CQ', highlighting when it spots matching transmissions. All you do then is click it, and your tuned and decoding that transmission ready to reply!
First few goes with this then, once set up, I started to reply to CQs, and was very pleased to be answered and make the contact. Tally so far is just a few inter-European QSOs, France, Spain, Germany, Poland. But as a first trial at just 5w (the power of my cars brake light!) its very encouraging. I still haven't fully mastered the macros yet, so don't always get it exactly right, but I'm sure with time that will come.
I want now to get or build a low cost, QRP PSK transceiver, for demo use, to show just how accessible the hobby is. I'm looking for a 20m version of the Warbler-80, which is very simple, but does use specialist crystals. I'd very much like to build a PSK-20 from small wonder labs, but they are now closed as the proprietor has retired. However I have been offered one complete, if its a sensible price I may go for it.
PSK-31 seems to be ideal demo material. Simple kit, low cost, and can be run from laptops, tablets etc. It should appeal to prospective, tech savvy youngsters. It also has the advantage of low power operation, and for those who need to keep quiet, can be done with no sound at all! Ideal for late night operating.
Back to WSPRing
Its been sometime since I worked on the 10m Wispy transceiver, and im still not convinced by the results on Tx that I was seeing. However, I do think that its probably my test setup thats at fault here.
I now though have a more pressing reason to get this project working - CHOTA! This year, I will be putting on a special event station for churches on the air, from the tiny chapel of St. Mary's, Lead. A WSPR or PSK-31 demo station would be ideal for this event, so out comes Wispy again for another go.
I have yet to build the receive strip, so plan on doing so and getting that working before having another crack at the transmitter side. I have also requested help from a 3rd party to check the project over and see what is amiss with it (if anything!). In order to help eliminate the test setup as a source of problems, I will in the next few days knock up a battery powered two-tone test oscillator, an Altoids special! This will give me a supply and ground independent audio source.
Others have replicated the Wispy without major trouble, so im sure its either something im doing wrong, or something wrong with my test set-up.
Once it is working on both receive and transmit, I plan to work the PA a little to give 2w DSB (1w SSB equivalent) if possible, just to give it that little bit extra oomph, I also understand that with a little pulling the crystal can be shifted to put the rig onto the PSK-31 sub-band. If this can be done then I will make it switchable and use it for 10m PSK-31 as well as WSPR.
I now though have a more pressing reason to get this project working - CHOTA! This year, I will be putting on a special event station for churches on the air, from the tiny chapel of St. Mary's, Lead. A WSPR or PSK-31 demo station would be ideal for this event, so out comes Wispy again for another go.
I have yet to build the receive strip, so plan on doing so and getting that working before having another crack at the transmitter side. I have also requested help from a 3rd party to check the project over and see what is amiss with it (if anything!). In order to help eliminate the test setup as a source of problems, I will in the next few days knock up a battery powered two-tone test oscillator, an Altoids special! This will give me a supply and ground independent audio source.
Others have replicated the Wispy without major trouble, so im sure its either something im doing wrong, or something wrong with my test set-up.
Once it is working on both receive and transmit, I plan to work the PA a little to give 2w DSB (1w SSB equivalent) if possible, just to give it that little bit extra oomph, I also understand that with a little pulling the crystal can be shifted to put the rig onto the PSK-31 sub-band. If this can be done then I will make it switchable and use it for 10m PSK-31 as well as WSPR.
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