fv1609

It's back again now PS Oh no its not. Comes on for 10 seconds then shuts when you move around site

ebay down again in case you were wondering if you had a fault http://www.isitdownrightnow.com/ebay.co.uk.html

Iain glad the Round Tables are still going strong. I never went to the Martlesham ones just the ones at IBA Crawley Court. Yes G4DDK rings a bell. I dropped out of this 30 years ago the leading light in those days was G3BNL Cheltenham (so you can guess where he worked) he developed the 1152 magic number concept for multiplying up. But in time it was best to build a transverter separately for each band rather than a single driver. Rather like a power drill it is better to have a separate, hedge trimmer, jigsaw etc rather than keep fiddling with attachments all the time. Although I could get TWTs that came out of service after so many hours link use, they required large external mounts. The breakthrough for me was getting hold of some Litton TWTs compact & with N terminations they were quite wide band. In fact I still have them & the PSUs. But they were only 1-2 watts. In my tropo era it was G3YGF at Oxford University & G3JVL at Hayling Island that led the way & I happened to be under their path. At that stage I was given a GASFET preamp which was quite something in those days. There was a student at the time G8NDJ who really threw himself into construction & a couple of years ago I gave him the more usable parts of my gear, which I believe still works. But he is now very good at spotting bargains for the right bits of sat stuff that can be modified. I've really got left behind by it all, but although my accounts might seem a bit self indulgent it might illustrate how things have gone from being confronted by "they can't make transistors that work on 70 cm" :-D

Thank you Roger. The FT290R is a useful little thing for home or portable. I really only used it as an IF for the transverters, but it was a very useful building block. Yes a black box, once it was argued that a true amateur would have built a compact transceiver, but I would sooner use an integrated circuit than built up the equivalent thing with dozens of transistors! You have to use these building blocks to get them to do what particular project that interests you. Amateurs love to adapt things & a lot of my earlier stuff was based on scrap radar equipment & old GPO links. I think my first 13cm rig was based on the first microwave link to the Isle of Wight. Early narrow band PCB oscillator driver boards were based "balloon boards" ie the transmitters contained in met balloons. I understand now that certain satellite TV amplifiers can be tweaked into low power PAs. Going back to the FT290R I still have mine but it has not been turned on for 30 years! I believe there is a charging process to be used to help reform the electrolytics so they don't pop. Iain, yes Martlesham was focus of a lot of early amateur microwave activity as well as the professional role! Yes a comms vehicle is the way to go. I have a 1 Ton Cipher Office that would be ideal for that sort of thing, if I turned my mind to it. I understand that there there is really no home brew on 3 cm. Apparently there is a solid state transverter module made in Germany costing several £K that is widely used. delivering 1 watt & this is high power when you remember klystrons & Gunns gave 5-10 milliwatts. Makes my TWTs & hombrew stuff seem primitive. I have given the transverters away to perhaps the only remaining homebrewer on these bands & I understand they are still giving service. I still have the TWTS & PSUs. Here is the set up I had in my loft. This was remotely operated from my shack which was some distance from the mast & rather small. I just fed in 28 MHz & remotely selected the band I wanted to operate on. The only task was to change the feed in the dish. 10 GHz set up 5.7 GHz set up 2.3 & 3.4 GHz set up switched to the same TWT Note the 15mm pipe on the right is not part of my set up! Although in Bristol I used 22mm water pipe as circular waveguide that I fitted inside the mast.

I’m afraid this is going to be a long one! It is 50 years to the day that I received my Amateur Radio (Sound) Licence B. What disappointed me at the time was the snottiness of holders of Class A Licences who regarded the Class B Licence as a novice licence. Well as a schoolboy I passed exactly the same City & Guilds of London Institute Radio Amateurs Exam (RAE) as the holders of a Class A Licence. So our technical knowledge was required to be the same. I was not aware of any classes to teach you how to become a radio amateur, so I was self-taught from reading books & building equipment. What I hadn’t got was the Morse Test, I just wasn’t up to the required speed (12 wpm). But once a licence became available that didn’t require the Morse Test I jumped at it. Although since 1950 there had been a dodge to apply for an Amateur Radio (Television) Licence that just required the RAE & no Morse Test. The TV licensee enjoyed the status of a call sign in the G3 series suffixed with /T. Transmissions were restricted to UHF & above for television (& sound in connection with those tests). If the licensee passed the Morse Test the /T could be omitted for those communications not using TV. Later all TV licensees (including Class A & B) were issued with call signs to be used for these transmissions in the G6AAA/T series. Although I did later set myself up to receive amateur TV I had no interest in transmitting it. My first target was to get operational of the 420 – 460 Mc/s band (70 cm) In 1964 there were no transistors available that could work as high as 420 Mc/s. You either had to build a converter that simply went into a crystal mixer or the equivalent thing that in my case a naval P58 radar receiver. Very insensitive! I had to build a two-stage preamp using CV354 disc seal triodes. http://www.tubecollector.org/cv354.htm The step forward was to get hold of a “BBC 2 tuner” & bend it into the amateur band. The transmitter started with an 8 Mc/s crystal multiplied up to 432 Mc/s with QQVO6-40A in the PA. I would have been delighted to have discussed on 70 cm my so called “novice” licence with any holder of a “full” licence had they been capable of getting onto the band. I had my first article published in 1966 for Practical Wireless. Then moved from Devon to Bristol. As can be seen by the corner reflector I had just built, SHF & above was generally primitive in the amateur world. Forays onto 9 cm & 5 cm were with klystrons in polarplexers using circular wave guide feeding a dish. For 9 cm a beer can worked well & for 5 cm a Brasso tin. Provided the other station used the same I.F. (usually 30 or 100 MHz) you had true duplex with one station transmitting vertical polarisation & the other horizontal. A little coupling from the transmitting klystron gave the local oscillator injection for the receiver. For 3 cm waveguide (WG16) did crop up in scrap radar equipment. Klystrons with internal & external cavities were not too difficult to find. For 1.5 cm (21 GHz) there was nothing around surplus but a diode could be forced to double from a klystron bent to 10.5 GHz & produce some tiny levels of power in microwatts but gave results as dish gains were significant at these frequencies. (IARU Region 1 = Europe, Africa, Middle East and Northern Asia) 21 GHz was 1,000 Megs wide, sadly that disappeared. To be replaced by a very restricted allocation in 24 GHz. You had to get a permit for a location, specify your exact frequency & with whom you are going to contact & think the times you were going to operate. Something very strange went on in that band I think. But it’s funny how all these old pretty useless bits of the spectrum have proved to be so important these days! Solid state Gunn oscillators for 10GHz became easy to obtain & lent themselves to portable operation as they no longer required peculiar high voltage power supplies for klystrons. But this was wide-band FM with drift & no precise frequency determination. The breakthrough for me was to build a solid state 5 watt transmitter for 1152 MHz. This was a magic number when used in conjunction with varactor diodes allowing access to all the microwave bands available at the time: 1,152 x 2 = 2,304 MHz (13cm) 1,152 x 3 = 3,456 MHz (9cm) 1,152 x 5 = 5,760 MHz (5cm) 1,152 x 9 = 10,368 MHz (3cm) 1,152 x 21 = 24,192 MHz The above were NBFM (or CW) but as a bonus 1,152 + 144 = 1,296 MHz (23cm SSB) This allowed much more compact & safer equipment that lent itself to portable operation. Of course the established rationale was “line of sight” for microwaves. So we operated from hills & mountains, with South Wales providing some of the latter for me. Height was important between stations to clear intervening obstructions but also to allow extra height for the curvature of the earth. One was restricted to sunny day operating with a dish on a tripod & jolly good fun it was. But if it rained the equipment got wet & we all know how rain scatters microwaves (as in weather radar). So I looked for a more robust way of operating. This is when the military vehicles started for me. I purchased an FFR Lightweight from Brian Bashall (Dunsfold) & built in it a permanent 10 GHz solid state SSB set up. Yes & even still I would get the odd “novice licence” dig from “full” licensees. My comment would be yes let’s talk about how much of a novice I am on 10 GHz SSB (this was in an era when activity was predominantly still WBFM on Gunn oscillators). In those days microwave dishes were hard to get, there was no satellite TV (oh that’s where some of our spectrum went!) I used a battlefield dish but mounted it in a more delicate frame, I fixed this on a Decca radar scanner base & bolted into onto the roof. It was rotated by a windscreen wiper motor, I controlled this with a pulsed model railway controller so that I could turn the dish at a few rpm to a fraction of degree per second. The rotary waveguide joint fed into a waveguide relay that fed the RX or TX. The round black thing was a Magnesyn compass sensor that fed a display unit above the windscreen with a 400 Hz power unit. The dashboard housed a Desyn display from a radio compass in this instance fed from a Desyn sensor in the radar dish base. The reading from the Magnesyn compass gave my bearing which I then fed to the outer scale of the dish direction display, I corrected it for Grid North & thus had a complete display that would match my OS map. The transverter was built largely within the waveguide & the I.F. was 144 MHz from a FT290R. I could be operational wherever I travelled in a matter of moments, by simply raising the dish & setting the elevation to the horizon. This lent itself well to spontaneous & non-intrusive operation from beauty spots where a mast or tripod would be prohibited. Plus the appearance of the vehicle suggesting I was perhaps fulfilling some official role. Although I felt I had a rugged installation & could go anywhere in any conditions, for success one must have someone to communicate with. But nobody had kitted themselves up in a similar way. So much of my effort was wasted. Where I lived near Winchester was a poor location to operate from, but I found that I lay under a 10 GHz path used regularly by Oxford University to Hayling Island (sea level not “good” for microwaves). This made me realise I need not go out portable on a hill top again! I did pass the Morse Test & took out a Class A Licence. Not for HF but to assist in DX working on 10 GHz troposcatter. I moved house to an even worse location. Worse not due to height, surprisingly that is not too important, the requirement was a reasonable run at the horizon to get to the disturbances in the troposphere. But of course whilst it rained you could work from anywhere! So apart from a cross-over period in the 1970s, the attraction MVs has had a detrimental effect on my amateur radio. I now have a large pile of waveguide, klystrons, travelling wave tubes, mixers, slotted lines, wavemeters, power meters etc. I must thin these out so any enquiries are welcome. Sorry it has got rather long but the 50 years on the air (& we won’t talk about the bit before that) just kept coming!

Silly me! Yes I think you are right Derek. In the excitement I missed the metric bit :blush: such is my enthusiasm for Irwins!

Bryan I have some of these: http://www.ebay.co.uk/itm/Irwin-Industrial-Tool-Co-53901-Extractor-1-4-With-3-8-Drive-/331317148934?pt=LH_DefaultDomain_0&hash=item4d240a7d06 That single one is an expensive example but it shows how the tool cuts into the nut & grips the more it is turned. There are two main size sets available, I have both kits because they are fantastic.

John the EMER CI P400-409 states Clansman but this is from the 1982 index. So sorry no idea what preceded this.

Despite seeing quite a number of MV enthusiasts there on Saturday there was nothing that was of particular interest for me. But you never know! In past years I have come away with totally unexpected finds. This year just spent £3 on some heat shrink tubing

Super things, trade name is rather corny "ANDY" Well it does come in handy For small quantities as in Driver Servicing (whatever happened to that?) the Pig CES lists: Oiler, hand, 1/2 pt, force fed by pressure, rigid spout, LV6/MT1/4930-99-942-6907

Ok David thanks got it.

Link not working for me John even when I copy & paste.

I think actually it is 10B/615. An arrow is not necessarily indicative of WD merely of Government property. 10B is an RAF Vocabulary Section for wireless & radar, aerial & mast equipment & insulators.

Yes I feel rather sorry for them, not only because of the size reduction but wedged between them & the MVs is that extraordinary & to me pointless exercise of "tractor pulling". Not only does the noise of that go late into the evening (making barking dogs & generators seem really quite tolerable) but the black diesel fumes from these machines are serious & unpleasant. One exhibitor in our section needed regular medical attention because it triggered serious asthma attacks & nearly needed a hospital admission. The whole show for them was ruined. As for the poor souls in the "Collectables" section who were this year transplanted to end of the tractor pulling arena. When the pulling was on they were unable to be heard by visitors & had to evacuate or hide from the black fumes as they were general down wind of this as they were right next to the finishing line. I would have thought it might be fairer for all if the commercial section & the tractor pullers swapped location.

Yes (sorry I have to say something else because it won't allow me to just say 'yes')

Bingo! Found it, a page was stuck. FWD AF1 Application: Tasker Trailer 2-ton 4-wheeled

Richard my 1954 RAF Vocab 16E only lists two with similar codes: Butler BWD AF1 Lucas LWD AF1 So presumably the maker of FWD AF1 started with the letter 'F' Anyway the RAF Vocab says that the Butler & Lucas are completely interchangeable as complete units. Unlike most VAOS the RAF Vocab is good at giving the applications, but the applications here for both is given as "Universal" I'm afraid.

Ah that's what its called! It seemed to be making good headway although the gun thing was nosing down into the mud which didn't help. It stopped there for about 10 minutes I couldn't work out was the problem was. In general I did find it difficult getting many useful photos, because once people have taken their photos then they stand around in the way or get up close & then just stand there. I'm sure that they would be quite annoyed if someone did that when they were taking their photos!

Although it took an hour to book in on Tuesday (this was down to the wet weather with most entry lanes closed), it only took 15 mins to leave today. In the last couple of years the organisers have taken a pragmatic view & close the show at 3.00pm. A reduced entry fee is charged on the last day & people who have long distances to travel with their exhibits have a good head start for the journey. Something that other larger shows might consider, maybe.

Steve I did see it as I was intrigued by the anti balloon rockets. But didn't attempt a photo as it was so crowded in there. All my pictures are on my camera and I can't get them onto my phone as running on 3G. Although luckily I'm on O2 that have a mast set up and at least that is quicker than my broadband at home.

No rain today. Surprisingly the sun is shining. A nice evening. Still muddy underfoot in the very public areas. The WW1 displays were appropriate and well presented. I'll try and get some pictures up later.

It was actually pushed onto site. But yes it is very muddy they closed the pre paid public camping late afternoon. I heard of someone who had travelled 200 miles with caravan to join parents and was turned away and was left to fend for himeslf. So I can imagine there will be many such dissapointments. Exhibits all seem to be here. Walking around not too bad until you hit a thoroughfare. I notice the major pedestrian crossing manned by 3 - 4 quite young safety officers are not always looking out for oncoming traffic and have heads down texting or twitting. Quite a lot of spaces in market trading area but no great loss for me. Found no bargains in autojumble. But pleasant company in MV section

Phew just about caught up with you Terry. I've got them all so I can do some pruning at leisure now. Many thanks.

Got those as well Terry. Many thanks.

Ok thanks Terry