[ARC5] BC-455 adventure

[Bill Cromwell]

On Sat, 2012-06-16 at 11:37 -0500, David Stinson wrote:
> Specifically which screws are missing?
> Missing the entire cover or just the lid
> over the tubes?  How about the one over 
> the tuning cap?  Painted or bare aluminium?
> Is your QRZ address good?
> 
> I recommend running the receiver at under 200 VDC,
> Preferably 90-140 VDC or so.
> You won't notice much difference in performance,
> but those 70-year-old parts will thank you.
> 
> 73 Dave S.
> 

Hi Dave...
...Everybody,

A whole bunch of those small screws and washers that hold the sheet
metal together are missing. This one is down to one or two screws per
side. There has been reference recently about those and where to get
replacements. I can do the search for exact details.

The missing piece is just the cover over the tubes. Inside, the cover
over the tuning cap is there. I used a pile (pun intended) of 9 volt
batteries to put 180 volts on the B+ and heated it with a 24 volt AC
power transformer. I was pleased that after a small warmup time with the
heaters on there was 'insignificant' drift. I have run my R-23 and
BC-453 receivers down to 90 volts and all worked okay. I am going to
build another power supply or two to take care of those receivers with
somewhere from 90 to 150 volts (depending on what's in the junk box).
They were designed to run from 24 (28) volts DC on those heaters so I'll
accommodate that, too. I didn't notice any hum with the AC on the
heaters. The unit I have was recapped so it could take full voltage but
I think there is more to consider than just those caps. 

This one is dressed in black. It has been stenciled "BC-455-B" in yellow
and the metal tag says the same thing.

I had thought about adding regeneration (Q-multiplier) in the IF but I
am going to sweep align the IF to get it as narrow as I can and then try
to use audio filtering and some other, outboard audio tricks to help
sort signals. If that doesn't work well enough I'll do the Q-mult
approach. I read the specs. Not very CW friendly.

My address on QRZ is good. For mail the PO Box must be included. Even
UPS and FedEx hand off to the Post Office much of the time. This here is
the boondocks!

Thanks for all of your interest.

73,

Bill  KU8H