[ARC5] Re: Getting an "ARC-5 " Transmitter Running

[Roger Basford]

Hi All.

I've taken advantage of the post-Xmas public holidays over here to do some 
work on the four BC-series Command TXs here.

Following the recommendations by Dave Stinson recently I put together a 
suitable PSU and found that my BC-458-A and BC-459-A both work as acquired 
on eBay, one from the US and the other bought here in the UK. Both produce 
what I consider to be acceptable CW notes with just a trace of chirp, this 
was after fitting a 0D3 stabiliser to the oscillator HT line. HT on the 
final is 525V with 220V on the PA screen and 150V on the VFO, all measured 
key-down. Heater and relays supplies are taken from a pair of 100AH 12 V 
batteries in series. I think those levels fit pretty well with the 
parameters Dave suggested, and although he didn't suggest VFO rail 
stabilisation, it seems to help the note and there is less pulling of the 
oscillator when tuning up. I'm getting about 100ma of PA current when tuned 
up and about 0.5-0.6 amps antenna current into my 66ft doublet with the 
feeders strapped, tuned against ground and with a 365pf variable capacitor 
in series.

Next steps will be to clean the roller-coasters, run the tubes through my 
tester and change the triple 0.05 uF bathtub caps as per Dave's list and 
then take a look at the BC-696 and BC-457. Very impressed by the keying 
relays, who needs sidetone with those clunking away! :-))

HNY for 2005 to all,

Roger Basford, G3VKM




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