50MHz UKAC Contest

On arriving home last night from work, somewhat late due to attending a briefing from the glorious leader, I decided to have a bit of a tune around,

which led me to taking part in the last 40 minutes of this months 6m UK Activity Contest, bagging 15 QSOs in that time.

Bearing in mind that not all the results will be in yet, im currently 59th place, out of 66! Not too bad for a small chunk of the contest time and a fixed SSE bearing on a low 3-element Yagi.

Don't be scared of the scrap

Ive been doing a bit of skip-ratting recently. The main purpose of this is to womble up some more sheet aluminium. 19" rack mount equipment will often yield at least one nice big sheet of aluminium, or sometimes galvanised steel, from the covers. All very useful for making boxes and chassis for projects.

Most of the 19" racks units I end up with these days are, even when nominally of 'radio' equipment, digital beasts inside. And almost invariably all SMT! You might think that such things would be of little use in amateur radio.

But thats not the case. Take just one of these units, a now obsolete MPEG2 encoder. Lets take a 'walk' around the unit...

Theres a filtered mains input socket, lots of 75ohm BNC sockets, D type sockets, lots of push buttons and LEDs on the front panel, a very nice big backlit LCD unit. Hundreds of ceramic and electrolytic SMT capacitors, various crystals and crystal oscillator modules, voltage regulators, EMC filters.  On the boards there are SMT ICs that are useful - dual op-amps, SMT fuses and holders, latching relays. There are also numerous broadband RF transformers. So, just because its essentially a load of VLSI digital chips, theres still plenty of parts of use in old fashioned analogue radio building. And, of course, the hardware - M3 nuts, bolts, washers and spacers. Ali sheet, some plain, some perforated. Theres of course very useful high power and EMC clean SMPSUs, theres cooling fans, heatsinks, and connectors. Even some lengths of coax and ribbon cables.

Kit Itch

I feel the need to build a kit again, but really dont have any money spare. Its not so much the need to burn solder, as to bend metal!

So, ive plumbed for another el cheapo Chinese Pixie. I have an idea to knock up a little aluminium sheet cube, with a compartment underneath for the battery. Maybe even, a leaf spring telegraph key on top of the case! A small hole in the top with a plastic shaft down to the frequency pot.

I need to convince Bob M1BBV to get his antenna back up and get his morse key plugged in!

SOTA this weekend - and charity

This weekend, 18-19th June, as close to summer solstice as possible, myself and Bob M1BBV are again walking the Lyke Wake Walk for charity.

We plan to activate SOTA summits G/TW-001 and G/TW-002 at some time on the Sunday 19th, using 2m FM, so listen out for us!

And please, if you can, and especially if youve enjoyed reading my blog or if any of the info has been helpful to you, consider making a small donation to our nominated charity Meningitis Now,

to donate, simply click the link below!

http://uk.virginmoneygiving.com/team/Walkingenglishmen

Clansman Manpack Collection - Almost Complete

Many thanks to a chap by the name of Andrew in Glasgow, who has supplied me with the remaining transceivers for my collection of Clansman manpack radios.

These are the PRC-349s that also arrived for me at work yesterday. Now, these have no practical amateur purpose, but in a collection of 1980s British Army Manpack CNR, it wouldnt be complete without them. Described as handheld (if you have hands like shovels) these would be seen strapped to almost every lance jack or full screw you saw on the news from Belfast or Crossmaglen.

The pair obtained from Andrew are ex- ACF, and are complete to CES. Both are physically and aesthetically in excellent condition, as are the ancillaries  which in this kit are single earpiece and throat mic, pouch, and flexible whip antenna. It was for these that I was carrying out the battery cassette mods last night.

Modifying the battery cassettes for these radios to use 8x primary AA cells instead of 10x secondary NiCd or NiMH required just the shorting across of two of the battery spaces, as can be seen above. This is a good use for off-cut resistor legs!

Im glad I did this mod, as otherwise I might not have noticed that one of them needed its fuse holder resoldering! In order to show which battery positions are to be left unloaded, ive marked them with a red dot

Eventually, after he evaded me for several hours, I managed to collar my lad Sam, strap one of these on him, and get him to air test them with me! Earlier today I popped into Wilko's and bought a load of alkaline AAs for them.

The other new to me radio is the PRC-350, already mentioned. Now, a quick check of this for the 'confidence' noise with it hooked up to a bench PSU showed promise, but putting ten C cells into the battery cassette (modified like the '349s for alkaline cells) failed to power up. Much scrubbing and scraping of terminals later, even using washers and foil to make better contacts, and I eventually managed to get a 15v reading from the terminals (breaking one of them in half in the process!). But on connecting to the radio, it still wouldnt power up, and measuring the terminal voltage showed a staggering drop to 7v!

Inside the PRC-350. Flexi in abundance

 A check on the bench PSU showed that the radio takes 150mA on receive. This really shouldnt be enough to hurt a bank of C cells, even el cheapo zinc chloride 'JCB' brand from Home Bargains! (where I also bagged another head torch for 30 bob). I started to have a suspicion that what I was seeing was some spurious resistance somewhere. So, I checked the terminal voltage of the ten C cells just laid end to end - 16.7V. Then I put them back in the cassette and measured its terminal voltage - 16.44V. Doesnt sound much does it? But its enough to show that somewhere there was more resistance than is healthy in a DC supply! And it turned out to be a badly corroded crinkle washer and screw holding the negative terminal! Some careful scraping later (yes I will replace these with nice shiny new ones eventually) and the resistance was eliminated, and the radio now powers up on battery

Electrically, it seems ok. Physically, apart from the very bashed paint, missing audio socket dust caps and worn labels, the only issue the set had was that the battle antenna socket was so badly worn that putting the antenna on caused it to turn and the antenna fall over! Luckily, when I replaced the socket on the PRC-351, I ordered several, and so that was quickly changed and now the antenna stays where its put.

I could do with the proper carry straps for this radio, but they are not essential.

In terms of man portable Clansman equipment, my collection now includes 2x PRC-349, PRC-350, PRC351/352, and PRC-320. That only leaves the PRC-316 (A16), PRC-344, and PRC-319. Of these, the 344 is a UHF air to ground radio of no use whatsoever. The 319 is a 10ch HF voice and burst data transceiver that sells for stupid prices, and the 316 isnt really a Clansman, just a very late Larkspur set. I think I have all the actual radios I want now. Just a few remaining ancillaries to collect!

Clansman Battery Cassettes - Using Alkaline Batteries

The PRC-350 is a nominal 15V supply, from a cassette of 14 1.2V NiCds (actually around 17V). Its clear that putting fourteen alkaline cells in there could damage the radio (21V).

Ideally, to allow either NiCd/NiMH or Alkaline cells, I would use dummy cells to fill the unused spaces. But I dont have any. Luckily, someone on one of the forums has worked out a way of adding a wire link to the terminal cards that effectively bypasses four cells.

The same applies to the PRC-349 (although I know that it can survive a brief run at 15V as ive just tried it!), this uses a 10 AA cell cassette to give 12V from 1.2V NiCds. Again, for alkalines, I really need to work out a scheme to allow me to bypass two cell positions. Perhaps here the easiest way might be some pieces of dowel with drawing pins in either end and an insulated wire between them!

Either way I now know how many batteries I need to acquire tomorrow! 16 AA's for the two PRC-349s, and 10 C's for the PRC-350

More on the PRC-349 tomorrow...

Apologies to Mike And Martin!

Ive just spent the evening in a blind panic that i'd lost the handset clip that I so much coveted and received at work today! Convinced i'd left it on the desk at work, I emailed my two colleagues who are on the night shift and asked them to look for it. They went so far as to search the bin beside my desk (which I know I left bread crusts in!)

Then, as I was replying to their email saying they couldnt find it, I suddenly realised that there was one place i'd neglected to look - inside the EKGSA satchel!

The EKGSA (Elevation Kit Ground Spike Antenna) allows the VHF Ground Spike Antenna to be mounted atop a 5.4m Racal mast. It comprises a mast adapter, a selection of three coax phasing lines, and inductor unit, 20m of coaxial feeder, and a satchel to carry it all in. It also includes a special throwing line spool with fixed plastic rings. This is used to allow the GSA to be raised up using a tree branch etc, in the absence of a mast.

At the bottom of the above photo, is the packet containing the missing handset clip! In the 'safe place' i'd forgotten about! Ive promised the lads at work that i'll be their 'brew bitch' when were next on shift together, in repayment for making them search my bin!

More Toys For The Collection

On arrival at work this morning, as I passed through reception I spied a box on the counter perporting to have at some time past contained spare parts for Landrovers. I needed not to look at the address label, as I knew immediately it was for me!

I knew this as I was expecting a parcel from Dom at LRseries Landrover Spares near York. The fact the box was there when I got there meant it arrived yesterday - next day delivery!

Now the photo above is of more than just this delivery from Dom, as around lunchtime I received an email from reception stating there was another parcel for me. The contents of that one have been added. Im not going to talk about that second box yet.

Doms box contained three items. One is just a spare handset clip. One of my handsets is missing a clip that would be rather useful to add to it. Another item in the box is actually several items - the Elevated Ground Spike Antenna kit, all complete and in good order, including the satchel. And the last item is the PRC-350 below

Including a battery cassette, which needs fourteen C cells, this is the 2W VHF radio. As you can see its pretty battered, and was supplied on a very much 'what you see is what you get' basis. Now, had this been an Icom or a Yaesu amateur set, i'd have given it a wide berth! But, I know something of the mentality of the average Tom - the fact that this is battered tells me that it spent a lot of time in use, not stuck gathering dust at the back of the sigs cupboard! That hints that the squaddies considered it a reliable set.

I am of course prepared for the fact it is likely to have issues. The battle antenna socket for a start is very loose and worn, but I have some spares of those. So far, the most I have done is to croc clip a 15V supply to it, and do some basic checks. In * mode, I get noise from the handset. With the antenna on, in L and W modes on Tx, I get sidetone. It seems to work. Tomorrow, if I have time, i'll put it on the test set and give it a proper going over.

A bit of something different! Finishing the Frog Sounds v3.0

As a break from the tension of working on the RT-320, I decided to finally finish off the Chinese Frog Sounds 40m QRP CW transceiver. Now, this has been sat on my bench in its case for a long time, waiting for me to be bothered to find a way of securing the case lid!

So, tonight ive found out a bit more sheet aluminium, chopped it out using the nibbler, drilled some holes in it, bent it 90 degrees on my Mighty Mini bender, and turned it into a pair of brackets. A few  Nutsert threaded rivets to put case screws into, and a few pop rivets to fasten the brackets permanently to the chassis, and its done.

Its all rather rough and ready, I might add nice Dymo labels later. Heck, I might even be tempted to try it out on air!

RT-320 Synth Mod-9/Decade Switches A/B Ribbon Cable connection tables

Aide memoir for myself -

Ribbon Cable Connections RT-320 Remote VFO Project
Ribbon	Wire No.	Synth Pin			Loom Wire No.	Function
A	1  (Red Key)	37			10	1kHz         1S9-5
A	2	1			7	1kHz         1S9-1
A	3	3			14	10kHz       1S8-5
A	4	4			12	10kHz       1S8-2
A	5	5			16	100kHz     1S7-1
A	6	6			17	100kHz     1S7-2
A	7	10			2	100Hz       1S10-2
A	8	11			1	100Hz       1S10-1
A	9	12			6	100Hz       1S10-6
B	1 (Red Key)	21			5	100Hz       1S10-5
B	2	22			3	100Hz       1S10-3
B	3	26			20	100kHz     1S7-6
B	4	27			19	100kHz     1S7-5
B	5	28			18	100kHz     1S7-3
B	6	29			15	10kHz       1S8-6
B	7	30			11	10kHz       1S8-1
B	8	31			13	10kHz       1S8-3
B	9	32			8	1kHz         1S9-2
B	10	33			9	1kHz         1S9-3

But, since this is a public viewable blog, heres what the above cables look like -

I'll now terminate these with SIL header sockets, which will prevent short circuit, but still allow easy connection.