Wednesday, 29 February 2012

Slowly, slowly

Well, bit by bit were getting there with the radios. The valve set now has the hardware finished, and the antenna rod mounted on two PVC standoffs. Apart from a bit of further filing to make the base stable again, and a few tiewraps to hold the rod in place, whats left to do now is the electronics. And as there really is only a handfull of parts in this set, that shouldnt take long at all. With any luck it will even work!

Thanks to one of the fellas on the vintage forum, we now have the postage stamp trimmers modified for the matchbox radios. I still need to find a couple of nuts to mount the trimmers with though.

Yesterday, i picked up three HF mobile antennas. Today, a boot lid mount and 3/8ths insert arrived. Well, ive ordered the wrong insert, and this one doesnt fit the mount. Im not sending it back, instead i'll modify it to fit. The mount is going on the bottom of the tailgate, to the left of the numberplate and just above the bumper. A short coax lead will then go in to the rig in the boot. Its not the most ideal location, but i cant yet find a suitable through roof mount for a 3/8th antenna that will fit between the car roof and the roof lining. I also have to decide whether to fit one or both M8 mounts. Not that i can use either yet, as i havent run the power cable from the battery to the boot yet. The seperation kit is on order but coming from Hong Kong so might take a while.

Quite looking forward to a bit of HF mobile though.

Saturday, 25 February 2012

Nice Box!

The Yaesu FT-857 doesnt have a proper S-Meter, instead it has an LCD bargraph that can be selected to show the various levels such as Signal strength, Tx power, ALC level, Discriminator balance etc. But an LCD is always a bit pants. Yaesu obviously realise this, and so on the underside of the control head theres a 3.5mm jack socket providing a meter output. So, a 100k pot, a small box and an old CB S-meter later, we have a nice add-on analogue meter -

The 0-V-0 plods on slowly. Most of the holes are drilled, two of the grommets inserted. One more grommet, a pair of standoff insulators, and the ferrite rod supports still to do, and then we can actually build the electronic side of the set! Couldnt get much done today due to spending most of the day refelting a shed roof.

More old electronic stuff gone on ebay today, including a Kenwood battery charger, some old dot matrix printer parts, the unsold ICs from last week, and my Alinco DR-130 mobile, which has developed a fault. Think i'll miss the old rig, its given me a lot of good service.

Friday, 24 February 2012

Kindle Katastrophe

Been on nights. To pass the time i borrowed Julies Kindle. Im quite getting into this device, its a lot better than i thought it would be. That said, i have loaded the entire back catalogue of sprat onto it!
I tried to connect and download a book at work, well the damn thing crashed! I was forced to reboot it, deeply! And when it finally came back to life, about half an hour later, it had no library! Oh heck! Went online to try and resync it to the stored library on Amazon, but oddly, it eventually recovered and showed all the original books, including the sprats! I decided then to download the books via USB!

Capacitor stock arrived yesterday, but i only picked them up today. Also with the order is a plastic box to build a ladder line break-out box with. This will allow me to add in extra lengths of line to the aerial feeder, to help the tuner match better. Eight 4mm terminals will provide the connectivity. I now think I have everything needed to complete the valve 0-V-0 regenerative receiver.

The audio filter project might be close to finish now. I started this thing sometime when i was about 16, only about 20 years ago! Its from designs in a Bernard Babani book. It really has taken me this long to finish, and all it needed doing was the signal wiring! Anyway, a quick inspection revealed a fairly obvious basic mistake - the regulator is in backwards! Its also the wrong regulator, being a 7810, when it should be a 7809. I'll get that sorted in the next few days, hopefully i havent destroyed the LM353 ICs that the HPF and LPF use.

Wednesday, 22 February 2012

Yet more parts

The cap connectors arrived today. They are a type that allows a component or two to be mounted right at the cap, which is good as theres a parallel capacitor and resistor to go there. Spent some time adding solder tags in apropriate locations, and working out how to do the wiring. Have had to fabricate some stand off insulators as well to provide terminals for some components. Yet i still cant get any further! I need to drill three holes to mount the stand-offs, plus two for grommets to let wires pass under the chassis. I also found i have none of the capacitors needed. So, an order to Bowood. Seems i may have tired Will out a little picking the order - ten each of every value from 1.2pF to 470nF! Oh, and a box sized to make the break in section for the doublets ladder line!

I really hope this radio works after all this effort!

Tuesday, 21 February 2012

Goods In/Out

A few more parts for the valve set arrived today, courtesy of Bitsbox. This is a company i find very efficient, although without the added personal touch of Bowood. However, their P&P is a shade less than Bowoods and they stock a few items different. So we now have the remaining terminal posts, the M3 hardware to do the ground and standoff terminals, and the regeneration control pot. I also decided to treat myself to a cheap analogue multimeter to aid setting up. I had a confirmation email from Electrojumble to say the top cap clips are on their way, and a chap from the vintage forum is helping with the 6BA screws for the matchbox sets. I think i'll build one of these for LW.

On their way out, go the twenty spare NKT213 vintage germaniun transistors, out to vintage forum members. Also, some of my surplus radio kit and batteries have sold on ebay, so thats a nice few bob towards mobile HF antennas.

Monday, 20 February 2012

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!

Friday, 17 February 2012

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.

Sunday, 12 February 2012

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!

Wednesday, 8 February 2012

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!