[ARC5] (Fwd) Re: that one cent command receiver - (long reply)

[Kenneth G. Gordon]

On 12 Apr 2014 at 16:40, Leslie Smith wrote:

> The output transformer is missing.

Fair Radio Sales has various ones of those. Any will work.

>  Ditto for the
> noise-suppression choke in the B+ line.  

You don't need that choke that unless you're operating the receiver on a 
dynamotor...although if you are really insistent on having one, I can send you 
one....or several. I take it you mean the 3 H job which is normally mounted 
on the side-wall at the rear opposite the audio transformer.

The smaller one, L-14, an RF choke, in the filament line is totally superfluous 
for our uses. I also have one of those if you really want one. The purpose 
was to filter noise off the aircraft's 24 VDC buss.

> "My" set isn't too dirty.  In the past I used "Dot's bath and tile
> clearner" on really dirty sets.

Hey! Thanks for that info. I hadn't thought of that.

> Since my set is already a junker I'm going to use it as an experimental
> I.F. 'back-end'.   I'll use it on 525, 715 and 1500kHz and experiment
> with breakthru from the BC band.  I've always wondered about BC
> break-thru when the I.F. is in the middle of the BC band.  (The BC-348
> seems ok, so maybe it can be done.)  The band-width in the '946 will be
> broader than I might get from a BC-453, but even on 40m I think the
> selectivity will be good enough for this beginner.

One of my Elmer's sold my Mother a BC-348 for me with which he had 
included a BC-946 as the "Q 5er" and it worked a treat. I was very grateful to 
both him and to my Mother.

> I bought a DC-DC converter from eBay (12v to B+).  I can select any B+
> voltage from 45 to 180 volts by changing a single resistor.  I hope I
> can keep the switching noise out of the '946.  I plan to experiment with
> the performance of the set as I vary the B+ supply.  I'm certain others
> have done this already, but I haven't.

Yes. I, for one. My conclusion was that 180 VDC is about the best, although 
for peak results, you MAY have to "mess with"  adjusting the screen voltage 
up a bit.

Kenneth G. Gordon W7EKB

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