[ARC5] BC-454-A, etc. Selectivity option found?

[Kenneth G. Gordon]

On 22 Jan 2014 at 16:16, Geoff wrote:

> Sounds like a recipe for birdie city.
> 
> Carl

Well, when I tried this in about 1970, I didn't hear any: but perhaps I didn't 
know what to look for either.

It was a bit cumbersome.

I did something similar in a Hudson "Hornet" using a Johnson Mobile 
transmitter back then: I used a BC-454 to operate on 75 phone. I connected 
the last IF output of the BC-454 to the input of the Hudson's radio tuned to 
1415 Khz, then connected the output of the Hudson's radio to a BC-453 
tuned to 262 KHz.

I was quite pleased with the result, atlhough it took up a lot of room under the 
dash.

For power, I had some sort of dual-vibrator job. I don't remember the make, 
but it was pretty popular at the time.

When keying the transmitter, the second vibrator would start and double the 
output voltage to 500 VDC. For receiving, it output 250 VDC.

I used one of those Master Mobile center-loaded jobs mounted in the center 
of the trunk lid.

The big mistake I made was to wire the keying relay to also ground the field 
winding of the big 6 V generator, bypassing the regulator, so that the output 
voltage wouldn't sag. I overdid it though: at speed, the output voltage from 
the vibrator supply was so high it shorted the plate bypass cap in the 
Johnson transmitter.

But, Boy! it sure worked great for a while.

Live and learn.

Ken W7EKB