[ARC5] 10 meter BC-454...update.

[Kenneth G. Gordon]

Last night, I removed the coil-pack and started to rewind the coils.

I began with L-1 the RF stage input coil.

There were two coils in there, both wound out of enameled #18 GA solid 
copper wire, both loose and wound very sloppily.

It was obvious that the original builder didn't know how to properly count 
turns, as instead of the 6 turns on the main coil as specified in the original 
article, there were a little more than 5 turns. This explained why the lowest 
the RF stage would tune to was about 27.3 MHz, instead of below 27 MHz.

The original tuning slug was still intact.

The second coil, a 4-turn link coupled directly through a piece of small coax 
to the front-panel mounted RCA jack, was very loosely wound over the top 
end of the main coil. I have to check to make sure this coil is actually wound 
over the cold end of the main coil, but I think it is.

However, at 10 meters, 4 turns is too many. I will reduce that to 2 turns at 
most.

I rewound, very neatly, the main coil with #20 enameled copper wire which I 
obtained at the local Michael's store. I wound it very tightly and then covered 
it with a layer of super-glue which I allowed to set. At this point, the coil 
doesn't move at all.

After I have rewound the link, I intend to cover the entire coil in some sort of 
proper coil-dope.

The next coil to be operated on is the oscillator coil. It is so loose on the form 
that if I put the speaker (matched to 500 ohms) anywhere near the receiver 
while receiving a 400 Hz modulated signal from my signal-generator, it 
immediately starts to howl from mechanically induced vibrations from the 
speaker. This is highly annoying.

I was very surprised, however, to find that even after having the receiver 
turned off and lying on my bench for several days, as soon as the tubes' 
filaments warmed up after being turned on, the signal-generator signal was 
heard loud and clear, and I didn't have to adjust the tuning to peak it up.

I also set my signal generator to 1415 Khz, and exactly centered the IF 
tuning. It was a bit off, despite my earlier adjusting it by ear on band noise, 
and doing the above brought the output up noticeably.

I then zeroed the BFO, offsetting it slightly to one side of the passband for an 
approximately 400 Hz tone. It was way off.

Kenneth G. Gordon W7EKB

"Courage is being scared to death but saddling up anyway."--- John   Wayne