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.

Rishworth

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.

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...

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.

Mobile HF

Right, so now we have an antenna mount on the roof of the car for HF work. The tailgate mount is still a work in progress. The new mount is an SO-239 type, pretty much an allrounder that will allow me to put on pretty much any antenna, or connect up the field masts and their antennas.

Tried the 20m antenna on it (after proving it with the MFJ-259 and Bird load) and got a nice match in a sensible portion of the band. But 20m was poor today generally, so no QSOs made as yet. The 40m antenna has rather a narrow usable bandwidth, so i will have to decide where to tune that for, im thinking about 7100kHz.

The 80m antenna, well, forget it! Usable bandwidth is tiny, and as for efficiency... Instead, im going to look at using that antenna, or rather its parts, to make a shorter antenna for one of the higher bands. I want antennas for 17m 15m and 10m. 10m theres enough cheapo commercial jobs, so probably go with 17m, which is a favourite band of mine. I'll use a shorting wire to find a point on the 80m antennas loading coil that matches 17m, then  remove the shorted coil section, and shorten the coil former physically. I might look for matches for the other bands as well, with a view to making it a multiband tapped antenna.

I also cut a 2m 1/4w whip for on the M8 mount. This is for use on those occasions when the 5/8ths would be socially unacceptable, or when i need something that will work on 70cm as well. For those occasions when i really need to be able to operate efficiently on the lower bands (down to 40m), im in the process of putting together a link/jumper dipole

Pop, pop, pop rivets!

OK, so not pop rivets, as yet. Planning the mobile installation, ive decided that a 'cage', in effect, is needed in the boot within which to mount the radio and ancilliaries. This is to prevent anything else in the boot from banging into them. The intention is to fabricate a L shaped frame from sheet aluminium or steel, and bolt this to the wheel arch and the floor of the boot. Within this, a shelf/frame will be fitted. The radio, tuner, fusebox, junction box, interfaces etc, will bolt to the frame or the inside of the cage. A DC socket will be provided as well.

This is where the pop rivets come in. They will be used to attach the framework. To attach the cage to the car, ordinary machine screws will be used, but the car bodywork will have 'nutserts' installed. These are rivet in threaded tubes, and provide a secure and simple mounting.

The tool and inserts to do the nutserts is on order. The pop riveter i'll pick up from ASK when next that way out. The only other thing i might need is a bending brake, to form the bends and flanges of the cage.

The 2.5mm2 DC cable has been routed along the left hand sill, but has not yet been fed through the firewall into the engine bay. This will be done when i have the necessary crimps and fuseholders to attach to the battery.

I had intended mounting everything on the left hand side of the boot, as this seems intuitive. But its not to be, as the spare wheel carrier goes right over to the left! On the right however, there is a 9" space between the wheel arch and the carrier cover board, just enough for the cage. It means i have to route the DC cable around the inside of the boot to the right hand side, but the signal and control cables (head cable, mic cable etc) can run up the right hand sill. Mounting on the right makes perfect sense, in a country who drive on the left, as it means the antenna will be mounted on the right of the tailgate, away from pedestrians, bikes and low branches. Its also, on my car, diametrically opposite the fuel filler cap!

I have to finish the HF mounting. This will need bolting to the car, then continuity testing to make sure the ground path is good, before final paint spray to match the car body, and laquering. Ground strapping will also be needed on the hinges of the tailgate.

I have installed the first Panorama M8 mount, roof center, for VHF/UHF. It currently got the 5/8th 2m whip on it, and working fine. But, I installed it with the view of the equipment being mounted on the left, so the coax routes down the left hand pillar. I'll need to correct this over to the right (which will also mean it doesnt cross over the washer tubing to the rear window!) but that means yet again dropping the headlining. I might wait to do that when i have the next mounts ready for the roof! I'll post the pictures of that install job in the next update.

As regards mounting the control head, i searched every possible location in the car, and short of getting a new stereo with DIN sized fitting, so i can mount it to the blanking plate, the only sensible place is to the right of the steering wheel, where the rig was in the old car! I havent decided on the speaker location yet.

Sams Valve Radio - Almost

Work started again today on Sams single valve regenerative set. Up to now this was dogged with troubles as it just simply didnt seem to work. Well, i sought advice from the chaps at G-QRP club, always a helpful bunch, and received loads of info back. It seemed the first task was to up the HT voltage.
So, I went out today and bought 10 PP3's from which to build a 90v B+ battery. Well, they only had six on the shelf, but the assistant was stocking the batteries up. She at first didnt think there were any more, but i spotted a box at the bottom of her trolly. A box of ten. So i bought the whole box. The end batteries, where the connections to the pack are, have had shrouded 4mm sockets soldered on, and then the whole lot taped over, so as to prevent any contact with the terminals. As new, it measured 98.8v! The smaller pack is the present heater battery, 6v, although reading a bit low, using 4x AA's. In the future i'll change this for four C or D cells.

This is the view of the front panel, the big knob, which incidentally isnt big enough with a 600pF variable capacitor, is the tuning, and very delicate it is too! The bare shaft is the regeneration control pot. The 6K7G pentode valve can be seen behind the panel. A bandspread capacitor may well have to be fitted.

It can easily be seen that there is very little to the radio underneath! The view from above shows the main components, the big 600pF air spaced variable, the valve, and the audio transformer. The ferrite rod antenna has had its main winding progressively reduced to bring the tuning onto the MW band at a sensible spot and now has only about 55 turns out of the original 80, the smaller winding is the 20t tickler coil.

In its present state, its possible to find a couple of stations during the day. I think the big problems now are that even with the transformer, the audio output into low impedence phones is poor, and the tuning is far, far too coarse.

Mobile mounts agogo

Ive taken the MB-400 mount off. As it turns out, its not that distorting the boot lid, it seems the boots not a perfect fit anyway! Ive decided permanent through body mounts are the way to go. Im not bothered by drilling the car, lets face it by the time i sell it it will be knackered. So, im building a mount to bolt to the tailgate by the number plate, using a right angle section of steel plate. Below this will be fitted to the car a cable gland, to take the RG-58 into the car. Im priming the mount,a nd when im next near A.S.K i'll get some matching touch-up paint, it will look like it was made for the car, which of course it is!

Tomorrow, if alls well, i'll go through the rigmorole of removing the internal panels and lowering the roof lining, in order to drill the roof and fit a Panorama M8 mount for VHF/UHF.

Theres no rush with any of the mobile install, as i havent received the seperation kit yet. But i might as well get the antenna mounts sorted and run the power cable if i can.

Talking of cable, i managed today to run the spare coax feed (from the broken 2m Slim-jim) up the side of the house and into the loft. I'll mount a BNC patch box somewhere up there, and then can try different antennas on it. The first i think will be a 10m dipole!

Mobile HF

The Sharman MB-400 mount is nice, strong and well made. Thats all you can say for it! Its four 4mm 3mm grub screws i doubt will hold out long, and the nice black paint coating is non-conductive - theres no ground path through the whole thing!

The 105ADT 3/8th mount didnt fit the 16mm hole in the MB-400. So, so carefull grinding, cutting and o-ring selection, and ive modified it to fit. Its attached to the car, but i feel that additional work will be required to create a usable ground path, probably straps from the mount to the bodywork.

Im going to test the antennas on it later using the MFJ-259B, and see what the whips are like, at the very least i'll be able to positively identify which is which. I still think a through roof mount is going to be best, although the whips are very long!