Right, so now we have an antenna mount on the roof of the car for HF work. The tailgate mount is still a work in progress. The new mount is an SO-239 type, pretty much an allrounder that will allow me to put on pretty much any antenna, or connect up the field masts and their antennas.
Tried the 20m antenna on it (after proving it with the MFJ-259 and Bird load) and got a nice match in a sensible portion of the band. But 20m was poor today generally, so no QSOs made as yet. The 40m antenna has rather a narrow usable bandwidth, so i will have to decide where to tune that for, im thinking about 7100kHz.
The 80m antenna, well, forget it! Usable bandwidth is tiny, and as for efficiency... Instead, im going to look at using that antenna, or rather its parts, to make a shorter antenna for one of the higher bands. I want antennas for 17m 15m and 10m. 10m theres enough cheapo commercial jobs, so probably go with 17m, which is a favourite band of mine. I'll use a shorting wire to find a point on the 80m antennas loading coil that matches 17m, then remove the shorted coil section, and shorten the coil former physically. I might look for matches for the other bands as well, with a view to making it a multiband tapped antenna.
I also cut a 2m 1/4w whip for on the M8 mount. This is for use on those occasions when the 5/8ths would be socially unacceptable, or when i need something that will work on 70cm as well. For those occasions when i really need to be able to operate efficiently on the lower bands (down to 40m), im in the process of putting together a link/jumper dipole
Tuesday, 24 April 2012
Sunday, 11 March 2012
Pop, pop, pop rivets!
OK, so not pop rivets, as yet. Planning the mobile installation, ive decided that a 'cage', in effect, is needed in the boot within which to mount the radio and ancilliaries. This is to prevent anything else in the boot from banging into them. The intention is to fabricate a L shaped frame from sheet aluminium or steel, and bolt this to the wheel arch and the floor of the boot. Within this, a shelf/frame will be fitted. The radio, tuner, fusebox, junction box, interfaces etc, will bolt to the frame or the inside of the cage. A DC socket will be provided as well.
This is where the pop rivets come in. They will be used to attach the framework. To attach the cage to the car, ordinary machine screws will be used, but the car bodywork will have 'nutserts' installed. These are rivet in threaded tubes, and provide a secure and simple mounting.
The tool and inserts to do the nutserts is on order. The pop riveter i'll pick up from ASK when next that way out. The only other thing i might need is a bending brake, to form the bends and flanges of the cage.
The 2.5mm2 DC cable has been routed along the left hand sill, but has not yet been fed through the firewall into the engine bay. This will be done when i have the necessary crimps and fuseholders to attach to the battery.
I had intended mounting everything on the left hand side of the boot, as this seems intuitive. But its not to be, as the spare wheel carrier goes right over to the left! On the right however, there is a 9" space between the wheel arch and the carrier cover board, just enough for the cage. It means i have to route the DC cable around the inside of the boot to the right hand side, but the signal and control cables (head cable, mic cable etc) can run up the right hand sill. Mounting on the right makes perfect sense, in a country who drive on the left, as it means the antenna will be mounted on the right of the tailgate, away from pedestrians, bikes and low branches. Its also, on my car, diametrically opposite the fuel filler cap!
I have to finish the HF mounting. This will need bolting to the car, then continuity testing to make sure the ground path is good, before final paint spray to match the car body, and laquering. Ground strapping will also be needed on the hinges of the tailgate.
I have installed the first Panorama M8 mount, roof center, for VHF/UHF. It currently got the 5/8th 2m whip on it, and working fine. But, I installed it with the view of the equipment being mounted on the left, so the coax routes down the left hand pillar. I'll need to correct this over to the right (which will also mean it doesnt cross over the washer tubing to the rear window!) but that means yet again dropping the headlining. I might wait to do that when i have the next mounts ready for the roof! I'll post the pictures of that install job in the next update.
As regards mounting the control head, i searched every possible location in the car, and short of getting a new stereo with DIN sized fitting, so i can mount it to the blanking plate, the only sensible place is to the right of the steering wheel, where the rig was in the old car! I havent decided on the speaker location yet.
This is where the pop rivets come in. They will be used to attach the framework. To attach the cage to the car, ordinary machine screws will be used, but the car bodywork will have 'nutserts' installed. These are rivet in threaded tubes, and provide a secure and simple mounting.
The tool and inserts to do the nutserts is on order. The pop riveter i'll pick up from ASK when next that way out. The only other thing i might need is a bending brake, to form the bends and flanges of the cage.
The 2.5mm2 DC cable has been routed along the left hand sill, but has not yet been fed through the firewall into the engine bay. This will be done when i have the necessary crimps and fuseholders to attach to the battery.
I had intended mounting everything on the left hand side of the boot, as this seems intuitive. But its not to be, as the spare wheel carrier goes right over to the left! On the right however, there is a 9" space between the wheel arch and the carrier cover board, just enough for the cage. It means i have to route the DC cable around the inside of the boot to the right hand side, but the signal and control cables (head cable, mic cable etc) can run up the right hand sill. Mounting on the right makes perfect sense, in a country who drive on the left, as it means the antenna will be mounted on the right of the tailgate, away from pedestrians, bikes and low branches. Its also, on my car, diametrically opposite the fuel filler cap!
I have to finish the HF mounting. This will need bolting to the car, then continuity testing to make sure the ground path is good, before final paint spray to match the car body, and laquering. Ground strapping will also be needed on the hinges of the tailgate.
I have installed the first Panorama M8 mount, roof center, for VHF/UHF. It currently got the 5/8th 2m whip on it, and working fine. But, I installed it with the view of the equipment being mounted on the left, so the coax routes down the left hand pillar. I'll need to correct this over to the right (which will also mean it doesnt cross over the washer tubing to the rear window!) but that means yet again dropping the headlining. I might wait to do that when i have the next mounts ready for the roof! I'll post the pictures of that install job in the next update.
As regards mounting the control head, i searched every possible location in the car, and short of getting a new stereo with DIN sized fitting, so i can mount it to the blanking plate, the only sensible place is to the right of the steering wheel, where the rig was in the old car! I havent decided on the speaker location yet.
Wednesday, 7 March 2012
Sams Valve Radio - Almost
Work started again today on Sams single valve regenerative set. Up to now this was dogged with troubles as it just simply didnt seem to work. Well, i sought advice from the chaps at G-QRP club, always a helpful bunch, and received loads of info back. It seemed the first task was to up the HT voltage.
So, I went out today and bought 10 PP3's from which to build a 90v B+ battery. Well, they only had six on the shelf, but the assistant was stocking the batteries up. She at first didnt think there were any more, but i spotted a box at the bottom of her trolly. A box of ten. So i bought the whole box. The end batteries, where the connections to the pack are, have had shrouded 4mm sockets soldered on, and then the whole lot taped over, so as to prevent any contact with the terminals. As new, it measured 98.8v! The smaller pack is the present heater battery, 6v, although reading a bit low, using 4x AA's. In the future i'll change this for four C or D cells.
This is the view of the front panel, the big knob, which incidentally isnt big enough with a 600pF variable capacitor, is the tuning, and very delicate it is too! The bare shaft is the regeneration control pot. The 6K7G pentode valve can be seen behind the panel. A bandspread capacitor may well have to be fitted.
It can easily be seen that there is very little to the radio underneath! The view from above shows the main components, the big 600pF air spaced variable, the valve, and the audio transformer. The ferrite rod antenna has had its main winding progressively reduced to bring the tuning onto the MW band at a sensible spot and now has only about 55 turns out of the original 80, the smaller winding is the 20t tickler coil.
In its present state, its possible to find a couple of stations during the day. I think the big problems now are that even with the transformer, the audio output into low impedence phones is poor, and the tuning is far, far too coarse.
So, I went out today and bought 10 PP3's from which to build a 90v B+ battery. Well, they only had six on the shelf, but the assistant was stocking the batteries up. She at first didnt think there were any more, but i spotted a box at the bottom of her trolly. A box of ten. So i bought the whole box. The end batteries, where the connections to the pack are, have had shrouded 4mm sockets soldered on, and then the whole lot taped over, so as to prevent any contact with the terminals. As new, it measured 98.8v! The smaller pack is the present heater battery, 6v, although reading a bit low, using 4x AA's. In the future i'll change this for four C or D cells.
This is the view of the front panel, the big knob, which incidentally isnt big enough with a 600pF variable capacitor, is the tuning, and very delicate it is too! The bare shaft is the regeneration control pot. The 6K7G pentode valve can be seen behind the panel. A bandspread capacitor may well have to be fitted.
It can easily be seen that there is very little to the radio underneath! The view from above shows the main components, the big 600pF air spaced variable, the valve, and the audio transformer. The ferrite rod antenna has had its main winding progressively reduced to bring the tuning onto the MW band at a sensible spot and now has only about 55 turns out of the original 80, the smaller winding is the 20t tickler coil.
In its present state, its possible to find a couple of stations during the day. I think the big problems now are that even with the transformer, the audio output into low impedence phones is poor, and the tuning is far, far too coarse.
Tuesday, 6 March 2012
Mobile mounts agogo
Ive taken the MB-400 mount off. As it turns out, its not that distorting the boot lid, it seems the boots not a perfect fit anyway! Ive decided permanent through body mounts are the way to go. Im not bothered by drilling the car, lets face it by the time i sell it it will be knackered. So, im building a mount to bolt to the tailgate by the number plate, using a right angle section of steel plate. Below this will be fitted to the car a cable gland, to take the RG-58 into the car. Im priming the mount,a nd when im next near A.S.K i'll get some matching touch-up paint, it will look like it was made for the car, which of course it is!
Tomorrow, if alls well, i'll go through the rigmorole of removing the internal panels and lowering the roof lining, in order to drill the roof and fit a Panorama M8 mount for VHF/UHF.
Theres no rush with any of the mobile install, as i havent received the seperation kit yet. But i might as well get the antenna mounts sorted and run the power cable if i can.
Talking of cable, i managed today to run the spare coax feed (from the broken 2m Slim-jim) up the side of the house and into the loft. I'll mount a BNC patch box somewhere up there, and then can try different antennas on it. The first i think will be a 10m dipole!
Tomorrow, if alls well, i'll go through the rigmorole of removing the internal panels and lowering the roof lining, in order to drill the roof and fit a Panorama M8 mount for VHF/UHF.
Theres no rush with any of the mobile install, as i havent received the seperation kit yet. But i might as well get the antenna mounts sorted and run the power cable if i can.
Talking of cable, i managed today to run the spare coax feed (from the broken 2m Slim-jim) up the side of the house and into the loft. I'll mount a BNC patch box somewhere up there, and then can try different antennas on it. The first i think will be a 10m dipole!
Friday, 2 March 2012
Mobile HF
The Sharman MB-400 mount is nice, strong and well made. Thats all you can say for it! Its four 4mm 3mm grub screws i doubt will hold out long, and the nice black paint coating is non-conductive - theres no ground path through the whole thing!
The 105ADT 3/8th mount didnt fit the 16mm hole in the MB-400. So, so carefull grinding, cutting and o-ring selection, and ive modified it to fit. Its attached to the car, but i feel that additional work will be required to create a usable ground path, probably straps from the mount to the bodywork.
Im going to test the antennas on it later using the MFJ-259B, and see what the whips are like, at the very least i'll be able to positively identify which is which. I still think a through roof mount is going to be best, although the whips are very long!
The 105ADT 3/8th mount didnt fit the 16mm hole in the MB-400. So, so carefull grinding, cutting and o-ring selection, and ive modified it to fit. Its attached to the car, but i feel that additional work will be required to create a usable ground path, probably straps from the mount to the bodywork.
Im going to test the antennas on it later using the MFJ-259B, and see what the whips are like, at the very least i'll be able to positively identify which is which. I still think a through roof mount is going to be best, although the whips are very long!
Wednesday, 29 February 2012
Slowly, slowly
Well, bit by bit were getting there with the radios. The valve set now has the hardware finished, and the antenna rod mounted on two PVC standoffs. Apart from a bit of further filing to make the base stable again, and a few tiewraps to hold the rod in place, whats left to do now is the electronics. And as there really is only a handfull of parts in this set, that shouldnt take long at all. With any luck it will even work!
Thanks to one of the fellas on the vintage forum, we now have the postage stamp trimmers modified for the matchbox radios. I still need to find a couple of nuts to mount the trimmers with though.
Yesterday, i picked up three HF mobile antennas. Today, a boot lid mount and 3/8ths insert arrived. Well, ive ordered the wrong insert, and this one doesnt fit the mount. Im not sending it back, instead i'll modify it to fit. The mount is going on the bottom of the tailgate, to the left of the numberplate and just above the bumper. A short coax lead will then go in to the rig in the boot. Its not the most ideal location, but i cant yet find a suitable through roof mount for a 3/8th antenna that will fit between the car roof and the roof lining. I also have to decide whether to fit one or both M8 mounts. Not that i can use either yet, as i havent run the power cable from the battery to the boot yet. The seperation kit is on order but coming from Hong Kong so might take a while.
Quite looking forward to a bit of HF mobile though.
Thanks to one of the fellas on the vintage forum, we now have the postage stamp trimmers modified for the matchbox radios. I still need to find a couple of nuts to mount the trimmers with though.
Yesterday, i picked up three HF mobile antennas. Today, a boot lid mount and 3/8ths insert arrived. Well, ive ordered the wrong insert, and this one doesnt fit the mount. Im not sending it back, instead i'll modify it to fit. The mount is going on the bottom of the tailgate, to the left of the numberplate and just above the bumper. A short coax lead will then go in to the rig in the boot. Its not the most ideal location, but i cant yet find a suitable through roof mount for a 3/8th antenna that will fit between the car roof and the roof lining. I also have to decide whether to fit one or both M8 mounts. Not that i can use either yet, as i havent run the power cable from the battery to the boot yet. The seperation kit is on order but coming from Hong Kong so might take a while.
Quite looking forward to a bit of HF mobile though.
Saturday, 25 February 2012
Nice Box!
The Yaesu FT-857 doesnt have a proper S-Meter, instead it has an LCD bargraph that can be selected to show the various levels such as Signal strength, Tx power, ALC level, Discriminator balance etc. But an LCD is always a bit pants. Yaesu obviously realise this, and so on the underside of the control head theres a 3.5mm jack socket providing a meter output. So, a 100k pot, a small box and an old CB S-meter later, we have a nice add-on analogue meter -
The 0-V-0 plods on slowly. Most of the holes are drilled, two of the grommets inserted. One more grommet, a pair of standoff insulators, and the ferrite rod supports still to do, and then we can actually build the electronic side of the set! Couldnt get much done today due to spending most of the day refelting a shed roof.
More old electronic stuff gone on ebay today, including a Kenwood battery charger, some old dot matrix printer parts, the unsold ICs from last week, and my Alinco DR-130 mobile, which has developed a fault. Think i'll miss the old rig, its given me a lot of good service.
The 0-V-0 plods on slowly. Most of the holes are drilled, two of the grommets inserted. One more grommet, a pair of standoff insulators, and the ferrite rod supports still to do, and then we can actually build the electronic side of the set! Couldnt get much done today due to spending most of the day refelting a shed roof.More old electronic stuff gone on ebay today, including a Kenwood battery charger, some old dot matrix printer parts, the unsold ICs from last week, and my Alinco DR-130 mobile, which has developed a fault. Think i'll miss the old rig, its given me a lot of good service.
Friday, 24 February 2012
Kindle Katastrophe
Been on nights. To pass the time i borrowed Julies Kindle. Im quite getting into this device, its a lot better than i thought it would be. That said, i have loaded the entire back catalogue of sprat onto it!
I tried to connect and download a book at work, well the damn thing crashed! I was forced to reboot it, deeply! And when it finally came back to life, about half an hour later, it had no library! Oh heck! Went online to try and resync it to the stored library on Amazon, but oddly, it eventually recovered and showed all the original books, including the sprats! I decided then to download the books via USB!
Capacitor stock arrived yesterday, but i only picked them up today. Also with the order is a plastic box to build a ladder line break-out box with. This will allow me to add in extra lengths of line to the aerial feeder, to help the tuner match better. Eight 4mm terminals will provide the connectivity. I now think I have everything needed to complete the valve 0-V-0 regenerative receiver.
The audio filter project might be close to finish now. I started this thing sometime when i was about 16, only about 20 years ago! Its from designs in a Bernard Babani book. It really has taken me this long to finish, and all it needed doing was the signal wiring! Anyway, a quick inspection revealed a fairly obvious basic mistake - the regulator is in backwards! Its also the wrong regulator, being a 7810, when it should be a 7809. I'll get that sorted in the next few days, hopefully i havent destroyed the LM353 ICs that the HPF and LPF use.
I tried to connect and download a book at work, well the damn thing crashed! I was forced to reboot it, deeply! And when it finally came back to life, about half an hour later, it had no library! Oh heck! Went online to try and resync it to the stored library on Amazon, but oddly, it eventually recovered and showed all the original books, including the sprats! I decided then to download the books via USB!
Capacitor stock arrived yesterday, but i only picked them up today. Also with the order is a plastic box to build a ladder line break-out box with. This will allow me to add in extra lengths of line to the aerial feeder, to help the tuner match better. Eight 4mm terminals will provide the connectivity. I now think I have everything needed to complete the valve 0-V-0 regenerative receiver.
The audio filter project might be close to finish now. I started this thing sometime when i was about 16, only about 20 years ago! Its from designs in a Bernard Babani book. It really has taken me this long to finish, and all it needed doing was the signal wiring! Anyway, a quick inspection revealed a fairly obvious basic mistake - the regulator is in backwards! Its also the wrong regulator, being a 7810, when it should be a 7809. I'll get that sorted in the next few days, hopefully i havent destroyed the LM353 ICs that the HPF and LPF use.
Wednesday, 22 February 2012
Yet more parts
The cap connectors arrived today. They are a type that allows a component or two to be mounted right at the cap, which is good as theres a parallel capacitor and resistor to go there. Spent some time adding solder tags in apropriate locations, and working out how to do the wiring. Have had to fabricate some stand off insulators as well to provide terminals for some components. Yet i still cant get any further! I need to drill three holes to mount the stand-offs, plus two for grommets to let wires pass under the chassis. I also found i have none of the capacitors needed. So, an order to Bowood. Seems i may have tired Will out a little picking the order - ten each of every value from 1.2pF to 470nF! Oh, and a box sized to make the break in section for the doublets ladder line!
I really hope this radio works after all this effort!
I really hope this radio works after all this effort!
Tuesday, 21 February 2012
Goods In/Out
A few more parts for the valve set arrived today, courtesy of Bitsbox. This is a company i find very efficient, although without the added personal touch of Bowood. However, their P&P is a shade less than Bowoods and they stock a few items different. So we now have the remaining terminal posts, the M3 hardware to do the ground and standoff terminals, and the regeneration control pot. I also decided to treat myself to a cheap analogue multimeter to aid setting up. I had a confirmation email from Electrojumble to say the top cap clips are on their way, and a chap from the vintage forum is helping with the 6BA screws for the matchbox sets. I think i'll build one of these for LW.
On their way out, go the twenty spare NKT213 vintage germaniun transistors, out to vintage forum members. Also, some of my surplus radio kit and batteries have sold on ebay, so thats a nice few bob towards mobile HF antennas.
On their way out, go the twenty spare NKT213 vintage germaniun transistors, out to vintage forum members. Also, some of my surplus radio kit and batteries have sold on ebay, so thats a nice few bob towards mobile HF antennas.
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