OK, so this evening I found a few moments to complete the setup of PSU module 5, after its capacitor change. The fault remains as it was prior to the caps being replaced.
Most of the supply rails were pretty much as expected -
3v = 2.9v
6v = 6.0v
12v = 12.7v
24v = 25v (raw battery input)
110v = 108v
121v = 120v
The only thing amiss in terms of level here was the 110v rail, which the replaced capacitors are part of. A careful tweek once the set had settled down put this up to a steady 109.9v and the 121v to 121.1v.
However, there is, I believe, something odd going on with this rail! Monitoring it at switch on, it takes nearly 25 seconds to rise to 110v! During this time, up to about 50v the unready tone sounds, it then sounds momentarily a few times as the level climbs up over 75v, 90v and 100v and up to 110v. Im sure it shouldnt take nearly half a minute to reach 110v!
Something else ive noticed - at present im testing on the bench with no input signal. In this state, once the 110v rail has risen and the unready tone ceased, I get a nice steady low level of noise from the handset, no pops, clicks or static crashes, no sudden noise bursts. Whether adjusting the supply rail has solved that, or whether it is a function of having an input signal present (perhaps an AGC issue?) will have to wait until I can test further with an input signal present.
Thursday, 7 April 2016
Wednesday, 6 April 2016
PRC-320 Fault
My 'Test Bed' PRC-320, I may have mentioned, is faulty. How faulty I have yet to fully establish, but it seems some sort of power on stability issue.
Initially, I thought this would just be the expected leaky tantalums. So, I opted to replace these straight away. Module 9 has two of these
But after a bit of fiddling, and some cursing that my new soldering iron tip hasnt yet tinned properly, the capacitors were replaced, the modules rebuilt and reinstalled.
Sadly, the fault remains just the same. So its clearly not these capacitors that are the problem.
The nature of the fault is hard to explain in words. So, Ive made a video of it! The radio had been off and disconnected from battery for 24h prior to this, and was only reconnected to the battery immediately before I started filming.
It will be a few days before im in a position to start module swapping, so in the meantime im hoping to pick the brains of some more experienced users on the forums. It may be someone has seen this issue before and can give me a hint where to start checking. If not, and since it has a 'supply fault' feel to it, i'll start with module 5 and module swap with my other set (I want to swap the front panel and main case from this one to my main one anyway) to see what changes move the fault.
Ive also today ordered some crimping tools. I had already ordered one for the 2.54mm crimp terminals (annoyingly today I found it a quid cheaper!) but decided id add to these ratchet type tools with one for Lucas automotive terminals (spade/bullet crimps etc), one for RJ type audio/data connectors, and one for RG58 cable RF connectors.
I have also ordered the remaining coax needed for the PRC-352. This is being made up for me by Mark. Once I have this, then the 20W amp will be usable in anger!
Initially, I thought this would just be the expected leaky tantalums. So, I opted to replace these straight away. Module 9 has two of these
Physically removing the board in module 9 was fun! Getting it back onto the stack of PCBs and resoldering the wires was not! But, the two new 10uF 160v electrolytics were soon fitted
Module 5, the power supply, was a bit more fiddly. For a start, the two PCBs that make this up are held together with these tiny circlips, which are incredibly springy! The first one off took me about 15min to find again!
And once open, the modules capacitors, C6 and C8, both axial types, were a little harder to replace with modern radial devices
But after a bit of fiddling, and some cursing that my new soldering iron tip hasnt yet tinned properly, the capacitors were replaced, the modules rebuilt and reinstalled.
Sadly, the fault remains just the same. So its clearly not these capacitors that are the problem.
The nature of the fault is hard to explain in words. So, Ive made a video of it! The radio had been off and disconnected from battery for 24h prior to this, and was only reconnected to the battery immediately before I started filming.
It will be a few days before im in a position to start module swapping, so in the meantime im hoping to pick the brains of some more experienced users on the forums. It may be someone has seen this issue before and can give me a hint where to start checking. If not, and since it has a 'supply fault' feel to it, i'll start with module 5 and module swap with my other set (I want to swap the front panel and main case from this one to my main one anyway) to see what changes move the fault.
Ive also today ordered some crimping tools. I had already ordered one for the 2.54mm crimp terminals (annoyingly today I found it a quid cheaper!) but decided id add to these ratchet type tools with one for Lucas automotive terminals (spade/bullet crimps etc), one for RJ type audio/data connectors, and one for RG58 cable RF connectors.
I have also ordered the remaining coax needed for the PRC-352. This is being made up for me by Mark. Once I have this, then the 20W amp will be usable in anger!
Monday, 4 April 2016
Short Rod GSA
The GSA stands for Ground Spike Antenna. In RF engineering terms, its a base loaded half wave vertical. This kit comprises a spike, to mount the antenna in soft ground, a base unit, containing the loading/matching coil, a 6m long coax feeder, a short 40cm or so adapter coax for use with the PRC-350 radio, ten antenna rods, and a nice bag to keep them all in.
The original, and most common, version of this has a number of long antenna rods. This version has short rods, and twice as many of them! The idea is simple - put the rods together to give the element length needed for the frequency of operation.
I'll probably have a play with this live tomorrow. By running the analyser over it with each combination of elements, i'll be able to form a nice accurate table of element numbers, more accurate than the specified three lengths.
The 'test bed' PRC-320 is now opened up on the bench, the PSU module 5 removed and opened, and the covers off Synthesiser module 9, ready for the HV capacitor replacement tomorrow. I have a new bit for my soldering iron with a much finer tip, much better for this sort of work than the supplied chisel bit!
Clansman PRC-351 is now a PRC-352
Well its been some time coming, but I finally today got around to making my PRC-351 into a -352!
The Clansman PRC-351 is a 30-76MHz VHF FM manpack radio, with a (nominal) 3W output. To make it a 352 requires the addition of a 20W amplifier brick. I'd been meaning to get one of these amps, and a GSA (Ground Spike Antenna) to go with it, for some considerable time.
After arranging to buy these 'at some point' when I was next in the area, today I happened to be close to the seller on another, considerably more expensive, shopping spree (I needed new walking boots!) and was able to go and pick them up. The seller in question goes by the ebay user name of 2012mdlradios and turned out to be a real nice chap. We ended up spending about an hour just nattering about radio kit. This was a much better experience than ive had from certain other ebay Clansman sellers I could mention! (I'll just add at this point that good experiences have been with LR-series surplus and PTS Norfolk, and a few others have been 'ok', I wont however name a particular Wakefield based seller I dealt with face to face whos a right miserable sod, though im sure most people who have dealt with him will recognise the description)
Mark was a great fella, showed every item, and in fact allowed me to select which I thought were the best bits. Quickly what was the purchase of an amp and GSA became that and a SURF, and an ancilliaries bag (which I couldnt name for the life of me!) and probably would have been more if I'd not made the decision to limit the amount of cash I had on me!
So here it is in its PRC-352 format. The SURF is in great physical condition, so I added that for completeness of the system. The amp, whilst as aesthetically as scruffy as the rest of the radio, is a top performer! Rated at 20W, it gives me a good 21 and a bit at 70MHz, and a whopping 30W way down at 30MHz!
I need a coax cable to go between the 351 radio body (or the SURF) and the amp now, and this set is complete.
The Clansman PRC-351 is a 30-76MHz VHF FM manpack radio, with a (nominal) 3W output. To make it a 352 requires the addition of a 20W amplifier brick. I'd been meaning to get one of these amps, and a GSA (Ground Spike Antenna) to go with it, for some considerable time.
 |
| Basic PRC-351 set-up |
Mark was a great fella, showed every item, and in fact allowed me to select which I thought were the best bits. Quickly what was the purchase of an amp and GSA became that and a SURF, and an ancilliaries bag (which I couldnt name for the life of me!) and probably would have been more if I'd not made the decision to limit the amount of cash I had on me!
 | |
| PRC-352. PRC-351, 4W SURF, 20W amplifier, GS carry frame, 1.2m whip antenna |
I need a coax cable to go between the 351 radio body (or the SURF) and the amp now, and this set is complete.
Friday, 1 April 2016
Baofeng BF-888S UHF Handies on order
Earlier today, with the sun shining outside, I turfed my eldest lad and his mate off the X-Box and out to the local woods, to make best use of the good weather instead of staying indoors.
Sam asked me if they could borrow a couple of walkie-talkies. Im ashamed to say that they couldnt! Ive dozens of radios, handheld and mobile, of ex-PMR service - not an inter-workable pair between them!
So I decided i'd look and see what I could get that I could have programmed up for such instances. Well, I was aware of the low cost Baofeng BF-888S radios, and thought i'd see what the crack was with them,
I found a pair for a fraction over £16! A further £1.30 for the programming lead and software. This is just throwaway pricing! Assuming they actually arrive in working condition from China, these will do for the boys playing out.
Ive also ordered the rest of the 2.54mm plugs and sockets to complete my ability to make a decent job of connecting up to PCBs, and made an offer on a suitable crimping tool. I fully expect the offer to be rejected!
Sam asked me if they could borrow a couple of walkie-talkies. Im ashamed to say that they couldnt! Ive dozens of radios, handheld and mobile, of ex-PMR service - not an inter-workable pair between them!
So I decided i'd look and see what I could get that I could have programmed up for such instances. Well, I was aware of the low cost Baofeng BF-888S radios, and thought i'd see what the crack was with them,
I found a pair for a fraction over £16! A further £1.30 for the programming lead and software. This is just throwaway pricing! Assuming they actually arrive in working condition from China, these will do for the boys playing out.
Ive also ordered the rest of the 2.54mm plugs and sockets to complete my ability to make a decent job of connecting up to PCBs, and made an offer on a suitable crimping tool. I fully expect the offer to be rejected!
Wednesday, 30 March 2016
'Test Bed' PRC-320
Well, after some previous disappointments, I finally managed to get a second Clansman PRC-320 radio, for use as the development 'Test Bed' for the external VFO controller. Ended up paying a bit more than I really wanted though, but heyho,
In many ways im quite pleased with this one, all its front fins are good! and it has its original tuning chart. The battery clamps are a bit loose, as is the antenna socket, but other than that its only defects are the rear fin protecting the coax link broken off and a fair bit of scuffed paint...
... or so I thought!
Sold as 'tested and working' a few minutes of testing soon showed that this may be the case NOW, but it wont be for much longer, unless I step in very quickly with some repair work. It soon became apparent that the synthesiser was not locking correctly, and after about ten minutes would lose lock completely! Of course, I know what this unready tone means - the high voltage capacitors!
These capacitors provide the 110v line for the VFOs, and are metal cased tantalum electrolytics, well known for their poor end of life performance. Two of them are in the Synthesiser module 9, which is the oblong can on the right of the picture below (the one with all the circles on it), and two are in the PSU module 5, the big grey can front center.
Module 5 was found also to have a dent in the can lid! Luckily this just popped out with a bit of applied pressure. I have modern 160v radial electrolytics on order to replace these tantalum units, which should be with me by the end of the week.
At the top left of the radio and along the top of the cans, can be seen the pink wiring of the frequency decade switches. I will need to electrically disconnect these from all the synthesiser input pins, and the 3v supply to the switches, to prevent data contention. This is not going to be an easy task! And somewhere I also have to fit the microcontroller! The only space available is pretty much down the center line, between the IF filters and module 5, and the tuner turret!
So, Im now a bit miffed as to how to provide feedback to the seller. On the one hand, although working, as described, the unit has a clear fault condition starting to cause an issue, something that the seller should have noticed if the unit was indeed tested shortly prior to sale, which by the last years date on the tested sticker seems unlikely. But then, on the other hand, its a fault I can nip in the bud now, and the rest of the radio, and indeed the case, is better than I expected. I dont think it really deserves positive feedback, but then I dont think it really deserves neutral either!
Another aspect of the controller development for this radio will be obtaining serial comms to the external unit without compromising the seal integrity of the radio. For this, it is proposed to sacrifice one of the two audio ports. To see just what a squeeze that will be, take a look below
Thats the audio accessory board, in its nice tight little space in the rear panel beside the PA. Theres an aluminium panel goes over the top of this as well.
The final picture is just a view of the underside of the radio. There really is very little space inside these for any additional circuitry, so fitting in a microcontroller capable of reliably taking over the synthesiser control, is almost certain to require some clever SMD work!
In many ways im quite pleased with this one, all its front fins are good! and it has its original tuning chart. The battery clamps are a bit loose, as is the antenna socket, but other than that its only defects are the rear fin protecting the coax link broken off and a fair bit of scuffed paint...
... or so I thought!
Sold as 'tested and working' a few minutes of testing soon showed that this may be the case NOW, but it wont be for much longer, unless I step in very quickly with some repair work. It soon became apparent that the synthesiser was not locking correctly, and after about ten minutes would lose lock completely! Of course, I know what this unready tone means - the high voltage capacitors!
These capacitors provide the 110v line for the VFOs, and are metal cased tantalum electrolytics, well known for their poor end of life performance. Two of them are in the Synthesiser module 9, which is the oblong can on the right of the picture below (the one with all the circles on it), and two are in the PSU module 5, the big grey can front center.
Module 5 was found also to have a dent in the can lid! Luckily this just popped out with a bit of applied pressure. I have modern 160v radial electrolytics on order to replace these tantalum units, which should be with me by the end of the week.
At the top left of the radio and along the top of the cans, can be seen the pink wiring of the frequency decade switches. I will need to electrically disconnect these from all the synthesiser input pins, and the 3v supply to the switches, to prevent data contention. This is not going to be an easy task! And somewhere I also have to fit the microcontroller! The only space available is pretty much down the center line, between the IF filters and module 5, and the tuner turret!
So, Im now a bit miffed as to how to provide feedback to the seller. On the one hand, although working, as described, the unit has a clear fault condition starting to cause an issue, something that the seller should have noticed if the unit was indeed tested shortly prior to sale, which by the last years date on the tested sticker seems unlikely. But then, on the other hand, its a fault I can nip in the bud now, and the rest of the radio, and indeed the case, is better than I expected. I dont think it really deserves positive feedback, but then I dont think it really deserves neutral either!
Another aspect of the controller development for this radio will be obtaining serial comms to the external unit without compromising the seal integrity of the radio. For this, it is proposed to sacrifice one of the two audio ports. To see just what a squeeze that will be, take a look below
Thats the audio accessory board, in its nice tight little space in the rear panel beside the PA. Theres an aluminium panel goes over the top of this as well.
The final picture is just a view of the underside of the radio. There really is very little space inside these for any additional circuitry, so fitting in a microcontroller capable of reliably taking over the synthesiser control, is almost certain to require some clever SMD work!
Thursday, 17 March 2016
Back on 2m FM
A few days ago, I stepped out into the sun in the garden, with the intention of filling the bird feeders and clearing away the ivy from my main HF feeder.
... a few minutes later I was up the ladder installing a 2m monopole!
I hadnt intended doing it, but the nice weather and it just suddenly felt right to do some antenna works. To get the monopole up on the small mast, I first had to lower the 6m Yagi by a few inches, so took the opportunity to adjust the azimuth a bit as well. With this done and the monopole installed, I went off to decide what feeder to use.
Ideally it would have been cut to length, but I really couldnt be bothered with fitting N-types that day, so I used the pre-cut length of TFC-T10 that I used with this antenna on special events. This is far, far too long, so most of it is coiled up just outside the shack. I will get around to measuring and cutting it at some point, but being 75 ohm it needs a bit more care to get an exact electrical half-wave multiple, plus its aluminium braid and copper plated steel core, not the easiest to work with!
But, it seems to be working ok.
... a few minutes later I was up the ladder installing a 2m monopole!
I hadnt intended doing it, but the nice weather and it just suddenly felt right to do some antenna works. To get the monopole up on the small mast, I first had to lower the 6m Yagi by a few inches, so took the opportunity to adjust the azimuth a bit as well. With this done and the monopole installed, I went off to decide what feeder to use.
Ideally it would have been cut to length, but I really couldnt be bothered with fitting N-types that day, so I used the pre-cut length of TFC-T10 that I used with this antenna on special events. This is far, far too long, so most of it is coiled up just outside the shack. I will get around to measuring and cutting it at some point, but being 75 ohm it needs a bit more care to get an exact electrical half-wave multiple, plus its aluminium braid and copper plated steel core, not the easiest to work with!
But, it seems to be working ok.
Wednesday, 9 March 2016
Radio Magazine Archives
Everything looks good in hindsight, so they say. Back in the '60s, people said 'cor, wern't the 40s great!' - oh yes, doodlebugs, death, ricketts, wonderful! And now, people pine for the 'classic tunes' of yesteryear - the Ibiza tat 'duvva duvva' music of the '90s!
But one thing from the past that really was good - were the Practical Wireless magazines of the 1980s! Real articles, real projects.
Which brings me to the link below -
http://www.americanradiohistory.com/index.htm
A collection of whole scans of many radio and electronics magazines, back over the years. A massive collection, including PW, Wireless World (back as far as 1913!!!) and many others. Hours of nostalgic reading, and were everyone looks smart and wears a tie (and in an amazing number of the earlier magazines - smokes a pipe!),
So have a read. Browse the many interesting projects that you can still build. Yearn back for the old days of Bi-Pak and Home Radio, when Maplin still sold actual components at sensible prices with staff who knew what they were selling, when a Pye Westminster would set you back 50p, and when every town had a radio shop and a components shop, and the only place to buy silly cheap toy electronic tat was Tandys, when Radio Rentals actually rented out radios, and handheld radios needed both hands to hold!
But one thing from the past that really was good - were the Practical Wireless magazines of the 1980s! Real articles, real projects.
Which brings me to the link below -
http://www.americanradiohistory.com/index.htm
A collection of whole scans of many radio and electronics magazines, back over the years. A massive collection, including PW, Wireless World (back as far as 1913!!!) and many others. Hours of nostalgic reading, and were everyone looks smart and wears a tie (and in an amazing number of the earlier magazines - smokes a pipe!),
So have a read. Browse the many interesting projects that you can still build. Yearn back for the old days of Bi-Pak and Home Radio, when Maplin still sold actual components at sensible prices with staff who knew what they were selling, when a Pye Westminster would set you back 50p, and when every town had a radio shop and a components shop, and the only place to buy silly cheap toy electronic tat was Tandys, when Radio Rentals actually rented out radios, and handheld radios needed both hands to hold!
Saturday, 5 March 2016
Manpack fun with a big antenna
After repairing the Clansman antenna drop coax yesterday, and finding time today to finally connect my 2-way coax switch in line between the Alinco DX-70TH and the MFJ manual ATU, I decided to have a little play with the PRC-320 on a proper, big antenna for the first time,
The repaired coax connecting the -320 to the spare port on the antenna switch, meant that I could trawl the bands with the Alinco, a damn sight easier on the fingers! And then switch across to the Clansman once i'd decided where to operate.
The Clansman certainly holds its own in terms of receive! Ive not had a QSO on this setup yet, as ive just been tuning about, listening and seeing whats happening, plus, theres a big HF contest on at present, so im really not bothered about jumping into that melee!
Ive spent quite a bit of time today though helping Sam create his first 'sketch' on Arduino. We decided to start at the simple flashing LED, but then moved on steadily until we had recreated a set of Level Crossing lights! This caused us a bit of trouble, as we couldnt at first work out how to code for a transition from the steady amber to the alternating red LEDs! But after a bit of a think and some trial and error, I worked it out, and from there we went on to include a push button to simulate a train!
I'd intended today wiring my Clansman morse key to the plug from the second handset, but ive found that I cannot remember how to disassemble these plugs! After a lot of thinking back to my early days with ntl ive managed to open the plug up, but still cannot remember how to either undo the cable clamp, or remove the pins!
I could just use the whole cable I suppose...
The repaired coax connecting the -320 to the spare port on the antenna switch, meant that I could trawl the bands with the Alinco, a damn sight easier on the fingers! And then switch across to the Clansman once i'd decided where to operate.
The Clansman certainly holds its own in terms of receive! Ive not had a QSO on this setup yet, as ive just been tuning about, listening and seeing whats happening, plus, theres a big HF contest on at present, so im really not bothered about jumping into that melee!
Ive spent quite a bit of time today though helping Sam create his first 'sketch' on Arduino. We decided to start at the simple flashing LED, but then moved on steadily until we had recreated a set of Level Crossing lights! This caused us a bit of trouble, as we couldnt at first work out how to code for a transition from the steady amber to the alternating red LEDs! But after a bit of a think and some trial and error, I worked it out, and from there we went on to include a push button to simulate a train!
I'd intended today wiring my Clansman morse key to the plug from the second handset, but ive found that I cannot remember how to disassemble these plugs! After a lot of thinking back to my early days with ntl ive managed to open the plug up, but still cannot remember how to either undo the cable clamp, or remove the pins!
I could just use the whole cable I suppose...
Friday, 4 March 2016
Making Good
After a small bit of discussion with my seller, an amicable arrangement was reached with regard to the Clansman coaxial cable found to be faulty on receipt. Without going into detail, lets say that an agreement was reached whereby neither of us are significantly out of pocket.
As such, it meant that I could no crack on with effecting repair of the cable. Now, I have to say it wasnt quite as straightforward as expected, as the connectors internal layout, insulator spacing etc, was a little unfamiliar. But, a repair had been made
Now, with the analyser on one end, and the test load on the other, the VSWR is 1.1:1 or better across the MF, HF and VHF spectrum from 2 - 175MHz. As it should be!
Ive also, since the iron was on, got a bit further with the balanced charging cable for the Clansman LiPo battery. I need now to make note of the colour code used, and sleeve the cable, before soldering on the D type connector for the battery.
I also received another Racal Clansman handset this week, in generally much better condition than the one I have, but with a small problem - the PTT sticking! After a fair bit of examination, I concluded that the pressel bar is probably slightly bent, not an easy thing to determine exactly. So, I swapped it with the one from my other handset! So now I have a good working handset with a webbing hook on it, and the older handset that now 'may' have a sticky PTT, something to fix later if need be.
Im still waiting on a few of the parts to complete the Theremin, so apart from adding some more Velcro to the tape measure antennas to make them stow away a bit easier, ive not done a great deal more radio or electronics wise.
As such, it meant that I could no crack on with effecting repair of the cable. Now, I have to say it wasnt quite as straightforward as expected, as the connectors internal layout, insulator spacing etc, was a little unfamiliar. But, a repair had been made
Now, with the analyser on one end, and the test load on the other, the VSWR is 1.1:1 or better across the MF, HF and VHF spectrum from 2 - 175MHz. As it should be!
Ive also, since the iron was on, got a bit further with the balanced charging cable for the Clansman LiPo battery. I need now to make note of the colour code used, and sleeve the cable, before soldering on the D type connector for the battery.
I also received another Racal Clansman handset this week, in generally much better condition than the one I have, but with a small problem - the PTT sticking! After a fair bit of examination, I concluded that the pressel bar is probably slightly bent, not an easy thing to determine exactly. So, I swapped it with the one from my other handset! So now I have a good working handset with a webbing hook on it, and the older handset that now 'may' have a sticky PTT, something to fix later if need be.
Im still waiting on a few of the parts to complete the Theremin, so apart from adding some more Velcro to the tape measure antennas to make them stow away a bit easier, ive not done a great deal more radio or electronics wise.
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