Thursday, 25 October 2012

SAQ UN Day Transmission

Feeling atrocious all night at work, despite the joys of pizza and free doughnuts provided by management. Mostly this was due to having a cold, but also the hassle of having a pocket of transmitters on the south coast failing due to incoming RBR failure. A nasty little high pressure pocket was causing tropospheric ducting all night, in fact i think the lads dealing with the final DSO had an easier time.

Coming home, and with the prospect of plenty of tasks in hand from Julie being away and the boys to look after, I decided to stay up for the UN day transmission from SAQ Grimeton. It was my intention to try an E-Field probe antenna for this, which i had started constructing the day before, having done the case work, layouts etc, and aquired the parts. As a 'back-up' I quickly strung a 45m longwire, which was only a few feet high, draped over things in the garden. This fed the laptop and Wolf DL4YHFs Spectrum Laboratory software, via a simple protective interface to the soundcard.

Well, the longwire ended up being the primary antenna, as when tested the E-Field probe drew nearly 50mA, sent the battery flat, and didnt receive! So, with the longwire set up,  I watched and listened for SAQ. When they began tune-up, I could just make out a signal. Of the transmission, I could make out a few V's being sent, but nothing more. This was disappointing, and probably due to the antenna being low and local noise. I need to get Sam to help me rig a proper long wire high up, to feed his receivers and the FRG-100, and also the VLF systems.

It turns out, that in my weakened, fatigued haste, I had misread the pin-out of the J310 FETs, and fitted them both backwards. Although the J310 has interchangeable source and drain, sadly the gate isnt!. Anyway, once these were refitted (not an easy job) the unit now only drew 5mA, and provided a signal. Phew, I hadnt killed the FETs. The signal was quite a bit weaker than on the longwire, GBZ from Anthorn was visible but nowhere near the strength as on the wire, but then, the wire was 45m long, and the E-Field probe antenna just a 1m whip!

All that remains, is to find a tripod or spike to fit the probe to for proper use. I do however, think its rather a nicely built unit

Heres an internal view, the circuit is build dead-bug, which is great for a simple circuit, until you need to fix it! I need to stick a bit of foam in to keep the battery from moving.

Slightly blurred photo, but this is the completed unit. Signal out from the 3.5mm Jack, BNC for the antenna whip, Ground terminal, and of course an on/off switch.

Wednesday, 24 October 2012


The Ferranti U1032 is now repaired and restored, its not probably working 100%, but its good enough to sit on the shelf as my workshop wireless, merrily playing away radio 2 or 4 depending what mood im in.

The photos below show some of the condition after repair

On the 20th, Sam and I went to the G-QRP club convention at Rishworth school. Armed with a wad of cash, and a list of wanted items as long as my arm, we set out searching the stalls. A donation of books to the children in need bring and buy a book stall, resulted in a donation of a book to Sam! Other stalls were equally generous and Sam aquired a number of free items! Sam in fact did better than me, as I never found a single item from my list! The resulting score - Sam 3, dad 0. Total items bought (not including pie and pies) - two battery holders and a colour burst crystal. I never even needed the crystal, but it was housed in a glass valve body, so i just had to have it. Two of Sams donated items were also crystals - one in a normal shaped glass holder, and one in wartime package.

Sams crystals are not on amateur frequencies, but I plan on using mine in a nice little one valve CW transmitter.

Sams donated book was a very old guide to building a morse practice set, including plans to make your own mechanical buzzer, naturally this is the part Sam wants to build.

Tuesday, 16 October 2012

Little by little

Two of the 47uF 400v electrolytics fitted inside the old TCC tripple can. The empty space of the can has been packed with foam, and a bitumen disk (cut from roofing underlay) used to seal the can, with the wires poking through. The first connection, the ground, has been made, but in order to get at it I had to replace the first of the 2uF electrolytics a bit earlier than planned. This took a bit of planning as the original axial part was much much bigger than the replacement 2u2 250v radial, so some extra wire and sleeving was needed. The first of the Hunts mouldseal 0.003uF has also been replaced with a new 3n3 400v polyester.

It looks like one of the waxies will need to be next, as its in the way of the wiring for the big caps.

Pop a cap in yer... er, cap

The spares have arrived from CPC. Once again, CPC have shown how ridiculous their handling charge is, by sending a handful of capacitors in a 5l box! Heres the box

And heres the contents
Why the heck they didnt just stick them in a jiffy bag i dont know! But hey, its not like its cost them extra to do it this way, since ive paid the full shipping cost of 4.9l of air!

Anyway, on a less bitter note, I do now have the caps needed for the restoration (save for the 22uF 16v, which amazingly were out of stock!). Sadly, the size of the 47uF 400v electrolytics is such that only two will fit in the original can.

The cabinet however cleaned up very nicely, heres how it looked before 
And heres how it looks inside and out now
The first job is the big can capacitor that can be seen at the top of the chassis photo, you can also see some of the Hunts waxies and the TCC oil electolytics that will also be replaced with shiny new modern aluminium and polyester devices
I dont expect much more to be required, but we will see when this is done and the set is powered up (with its nice new modern jacketed mains lead).

This coming saturday is the G-QRP club Rishworth convention, hopefully many more interesting parts will be found there. I have in mind to build a Rockmite...

Saturday, 13 October 2012

Ferranti Restoration

Its been a while since ive updated this blog, but apart from growing older and probably uglier, not much has changed. I operate more mobile HF now, and with the help of Steve G7TAO and Rob M1BBV, we recently ran GB1LDS at the Doncaster Show. Thanks also go to Geoff at FDSprint for creating the QSL cards, which are currently in print and should be with me to send out in the next working day or two

One project I have on the go at the moment though, will be getting documented on here. I have recently aquired a late vintage valve table radio, a Ferranti U1032. This doesnt look to need much work, but a few capacitors need changing, and it needs a good clean up. The capacitors are on order, from CPC. I dont normally like using CPC/Farnell or RS, due to their extortionate 'handling' charges for small orders, but they stock the high voltage ratings needed, where my normal suppliers dont. So the caps have proved to be quite expensive but I will then have a few spares.

I'll start getting photos of the radio on here soon.