Lotta Bottle

Many thanks to Phil G4SPZ, for the 6K7G, which arrived safe this morning. We now have the right bottle for the valve regen set. Hopefully the rest of the remaining hardware and connectors will arrive tomorrow, and the top cap connectors were ordered today. Surprisingly, the 6K7 is somewhat smaller than the 6V6, something i hadnt expected!


I did find a reasonably large vintage knob for it, but a bigger one would be better. A mock up with the 6V6 shows a bit better how it might look when operating

The matchbox radios are proving a bit harder to get the hardware for. I can find 6BA nuts and bolts, but in big packs at extortionate prices. But this is the last item to find, so we can modify the postage stamp trimmers. The jack sockets were easy to mod, simply a case of pulling out the tab until the inner terminal springs out, then resetting it closer, so the inner terminal now makes contact rather than breaking it when the plug is inserted.

I also put together a pack of 20x AAA duracell procells, to make a 30v pack, which actually reads 27.7v, which i think will do for the HT. I also completed the wiring on my active audio filter project, something i started building as one of my first projects, perhaps some 20 years ago! The LED isnt working, the lowpass filter has little effect, and the highpass filter no effect! The CW filter works, and the ANL possibly, although i didnt have a signal with the right noise to check it on! Both the HPF and LPF use a 9v supply, and its possible the regulator isnt working, so either their ok but fed wrong, or theyre buggered and will need new ICs!

Metal bashing

Having had little time as yet to play with my new toy, due to not yet having the appropriate cables for the vehicle install, work has commenced instead on one or two smaller projects.

Today has been spent metal bashing. Ive lots of sheets of salvaged aluminium, so selecting a nice anodised piece, proceded to carve it up using the grinderette (fastest way of doing it), to give a six inch square sheet with a 3/4inch lip, and a 6 x 5inch sheet. These have become the chassis and front panel, respectively, for Sams 0-V-0 receiver -


Only those large parts are as yet installed. The valve shown is a 6V6G, this is not the valve the set will use, it uses a 6K7G, but i have not yet received this. Its on its way to me from one of the kind chaps on the vintage forum. I have since found i have a 6K7GT, but they are not quite so picturesque! Its also not in the greatest of condition, the metal screen around its lower half has split and is hanging off, not sure if thats repairable. The ferrite rod antenna has a tapped coil for MW, the tap being to allow an external antenna. The smaller coil shown is the 'tickler' to allow regeneration. This is the third time ive wound that coil, the first was in antiphase, the second wound so tight it wouldnt move on the rod!

A few more holes are needed in the chassis, to allow fitting of earth tabs, power terminals, and the sides of the bottom of the cabinet. A pair of insulated uprights are also needed to hold the ferrite rod.

Ive also wound a deminuitive 60t ferrite antenna 37mm long, this will be the antenna of a ZN414 based 'matchbox' receiver.

Wakefield Rally

Went to Wakefield radio rally today. Got there just after opening time. Very few dealers this year, but was pleased to see two very good vintage parts stalls, plus a stall by wakefield ARS. Sadly, this was a silent key sale, but it seems the chap was a hoarder. First i grabbed a VHF/UHF Manual for i think it was £3. I then started rummaging. Eventually coming away with four big tubs or old parts, in one of which was a bag of NE602s, which are worth what i paid for the rest! I seem now to have aquired literally hundreds of vintage transistors!

Got a few parts i actually went for, inluding a nice 600pF variable for £3, some 250pF postage stamp trimmers and open frame jack sockets for the ZN414 matchbox radios, and a big stock of brand new ferrite rods.

Some of the ICs amongst the junk i got are of no use to me but still in packaging - there now on ebay. If only a few sell, i will have recouped the days spending!

I missed out on a spares or repair HF magmount with various loading coils, simply because i didnt think it would be cheap. The next chap to me asked the price, and when told 'a fiver' his eyes nearly fell out, his jaw fell off, and he couldnt get his wallet out quick enough! Its a shame, as that would have gone nice with my new toy...

Also, Sam asked me to bring him 'something interesting', well, for 20p I found a wooden bayonet mains plug!

Oh, and mentioning my new toy, thats something else i was looking for, an auto ATU to go with my new to me Yaesu FT-857!

Let there be lower wattage light

After some fun and games fathoming out how the kitchen lights had been wired, I now have four 4w cool white LED lamps working, fed from one 26w driver transformer.

It turns out that the supply mains went to one of the lamps, and from there broke off as two spurs, each spur feeding two more lamps as a daisy chain. It soon became aparent that i could reuse the wiring.

I had hoped to pull the feed to the lamp over the door (the one without a LED lamp yet) and keep that one as halogen for the time being, but it proved impossible to pull the cable, likewise there was no way to feed a temporary mains supply. So, that one is also wired for LED, and is awaiting a lamp.

A check of the energy monitor, showed that the lamps are taking the expected 16w. This will be 20w with the fith bulb installed. Thats quite a saving from the 250w the halogens took. With all the halogens converted to LED throughout the house, the consumption will go down from 550w to a meer 44w. And the MTF (mean time to failure) for the LEDs is quoted as 50,000h, against the 5,000h for the halogens. At £8.50 a throw, theyre not cheap, but at about £1.30 each, and needing ten to last the same lifetime, the halogens come out at £13! Assuming the lamps last as quoted, thats about £50 saving in lamps alone, and roughly £60 a year in electricity. It also means that if they all last their lifetime, i shouldnt need to change them for about 27 years!

Early Adopter

Being an early adopter of any technology is not something i would normally do. I like things to have been well tried and tested, and brought down in price, before i use them. I dont have a Blueray player! I dont have a HD TV. I certainly dont, and never will, have a D-STAR radio!

But, there is one technology that i'm happy to try out - LED. I have four 4w LED downlighters and a suitable transformer, ready to try out in the kitchen. The prospective savings over the halogen 50w units, over the lifetime of the lamps, is staggering.

But of course, the builder was never going to make anything in this house easy! And this is certainly the case with the kitchen lights. There is NO access panel into the ceiling void, and no access from above. So everthing has to be arranged and wired via just the five 5cm holes in the ceiling! The LEDs need to go in parallel, fed in a loop from the transformer. The halogens that are in each have their own transformer, and a mains spur!

I expect each of the five lamps to look like this. Hopefully they will all have a mains junction box, which will allow me to safely disconnect the feeds. Routing the new DC ELV cable through the void might prove to be fun!

Theremin and CW

Yesterday, I decided enough was enough, and that the power supply for Daz's theremin just had to be completed. So, with a mug of tea, and the fan heater running flat out, i ventured into the garage and cracked on. A bit of customising was required on the case, but the power supply is now finished. +/- 12v dual rail, independently fused, to a standard 5pin 180deg DIN plug. I can now, when i have the time, start working on the main Theremin circuit again.

I also built an incredibly simple circuit - a meter tester. This is nothing more than a 1M linear pot and a AA battery, housed in an old shaving stick. Yet, oddly, it doesnt seem to work properly! Everything seems to measure ok, but when on a meter, its all or nothing. Odd.

Since ive decided to make the concerted effort to master morse, I though as well that getting the practice oscillator running properly was in order. Up until now, the headphone output had a strange 'drop-off' tail on key up. The output transistor, a BFY51, was feeding the speaker via a 100uF electrolytic and a 100 ohm emitter load as a common emitter circuit. I suspect the cap was responsible for the problem with phones at low levels. I tested it today with the load resistor replaced by an audio transformer, and the speaker and phone socket on the secondary, and it seems to work just fine. Only problem, it no longer fits the box its in. So rebuilding it will have to await the Wakefield rally in a couple of weeks to aquire a suitable box.

The next little project is just that, little! I have a stash of ZN414 equivalents, and Sam has shown an interest in a matchbox receiver. Its a long time since i built a little AM receiver, so i think we'll have a go at this. Just need the matchbox!

Bent-Runner

Well, the weather has been dire today, far too cold and damp to put either mast up, or to run the coax. So, it has been indoor tasks only.

The VHF vertical doesnt fit on the top of the Clansman mast. I need a spare mast section to cut down to form an adaptor to allow mounting of antennas like this, but short of buying a whole spare mast, it might be hard to come by. Ive put the feelers out.

As for the telescopic mast, the big task was meant to be fathoming out suitable guying. I think a stay point at the 4m and 7m levels is needed, the bottom can still be held by the 1m level bungees, and the antenna wires will attach at the 8m level. Except for verticals, the top two sections are too thin to be of use. Ive a couple of sheets of PVC gluing together to make a thick rigid sheet from which to fabricate guying rings. As the mast tapers, each ring will be unique to its level, and so they will only fit in a set order. The other problem is tensioning the guys. The Dacron line i have, whilst incredibly strong, is very thin, some 2mm if that. £3 in Yeomans, i found a pack of ten 'bent-runners', ie guy line tensioners for tents. These have got big holes in them so i didnt think they would work, but the homemade one i fabricated earlier today the holes were too small, and passing the line through would be awkward. A quick trial with one of these and a length of the Dacron however and the seem to hold fast. I might have cracked that problem!

I have played some radio today, tried for HK0NA but the level of idiocy and QRM was astounding! Did work a SOS radio week station in Torquay though.

Antenna Work & VP8s

Up the side of the house today, removing the remains of the wind shattered 2m slim jim, and salvaging its coax. Luckily, the rain hasnt got into the coax, so that can be rerouted up the rear of the house and into the loft, where i can then use it as a test bed for smaller, short term antennas, with a dipole orientation N-S (so a chance to work the African continent on the higher HF bands!)

Anyone who knows me will know i have no fear of hights, but i hate ladders!

Ive already made an 80m inverted V for use with the 10m mast, plus a 10m J-pole. However, with the new year started and the offer of the SES for the Doncaster Show in september, somewhat more radical, practical and portable antennas are now needed! Apart from 2m FM (the mainstay of town SES'es) such a 2 day event calls for HF, and a selection of bands to cover eventuallities. Ideally of course, i'd be able to use any band, but that would call for a compromise of the G5RV type, and two masts, at least. This may be possible using mine AND G7PZLs 5.4m clansman masts, but it wouldnt be very high. So, a fan dipole/maypole design based on the 10m telescopic mast is needed. The question is - which bands?

In the past, ive found 80m to be a prerequestite for SES. So which others? 40 and 20? What about 15, 12, and 10m? Topband is out on the practicallity side, and 30m isnt needed as this will be a phone op.

Im going to test a few ideas out tomorrow based on the clansman 5.4m mast, at the very least to verify that it will take the 2m vertical without any issues!


On the operating side recently, not much! However, yesterday i was very pleased with my little tune around on 17m whilst taking a break from gardening. Heard VP8LP Bob, calling CQ, no replies, so thinks i, grab him if i can before the EU zoo arrives! So, i called him, little realising i was set to 10w. Anyway, to my immense amazement, he replies! I quickly hit the button to go to 100w, as 10 just wasnt going to be reliable, and instead hit the AM/FM button. A good few seconds later i was back in control, and Bobs phone is ringing! I QRX, he returns and we have a pleasent natter for a few minutes. I give my 73 as i need to crack on with the veg plots, but Bob asks if i'd like to work another VP8 before i go? (Having been after the Falklands ever since i got HF, then its a moot question!), turns out Zorro VP8DNT is visiting Bob, they quickly change over, and ive got two VP8s logged in 10mins!

80m Field Vertical

Im going to get cracking with this. I have a 10m fibreglass telescopic pole (a windjammer), for which i have already worked out a neat guying system using bungy cords, and have created a radial plate for it.

The proposed design is a top-center loaded vertical. The coil will be positioned 8 ft from the top, allowing that bit extra wire for capacity. Calculations show this should be about 55% efficient. Combined with my MKARS-80 giving 3-5w, this should let me have an erp of about 2w. Not great, but the real benefit is expedience - i can get this rigged at a portable site/summit in about 5mins

Im also considering a linear loaded coil vertical. But winding the coil every time i put the pole up would be slow, tedious and inaccurate. I wonder what a slinky streched over 30ft will resonate at???

QRV 6m

Well, ive not updated this for, ooh, i dunno, ages. Other things have taken the time.

Anyway. I now have the doublet back up, and its working ok. Its not perfect, but its working sufficient to make contacts, including some nicely impressive DX. Yesterday, on 17m, i worked Cuba with just 10w, for example.

The 3 element yagi for 6m is up, albeit on the 'test' mast, at about 15ft. 6m is very good at the moment, plenty of sporadic E to work.

The one thing that has struck me about working SSB on 6m, is the business-like operating. No messing about, reports and locators, and then clear, but at the same time not overly rushed. Very pleasurable short QSO's.

Im still considering the best way of securing the main mast to the side of the house, im not at all happy with expansion bolts into engineering brick, i just dont think they will hold well enough if they penetrate one of the voids. Im wondering about using a steel backplate and M10 threaded rod right through the wall for the top bracket, which will take the worst of the wind loading. The pole i have is steel, so its heavy. Maybe i should bite the bullet and get an aluminium pole ordered!

Julie is not particularly keen on the 6m yagi, so would be even less happy with the 9 element 2m Tonna. But if they were up at 30ft, perspective means they look smaller. They will also perform better!