[Boatanchors] 6AG7 160 meter rag chew ideas needed

[Robert Nickels]

On 11/16/2013 8:15 AM, David Stinson wrote:
> If you want your rig to work acceptably and stay on freq, "simple" and 
> "no crystals" are mutually exclusive. 

I have to disagree, although that was my thought too - before I created 
the "All American 75" conversion that was described in the Oct. 2013 
issue of Electric Radio (and a corrected schematic in the Nov. 
issue).     I get two watts out of a modulated crystal oscillator that 
is stable and simple to build, and which gets consistently good reports  
(such as S8 from stations 100-150 miles away this morning).    The AA75 
uses a 35L6 that's modulated by the existing 50L6 audio output stage 
using a simple Heising connection, which remains in use for the receiver 
portion.  I suspect that other beam power pentodes would be usable, but 
a five-tube 2 watt AM transceiver made out of a junk broadcast radio is 
pretty hard to beat, in my admittedly biased opinion!   The article 
describes how to convert the receiver and eliminate the hot-chassis 
shock hazard, but you can probably figure those things out for yourself  
(160 could probably be tuned by tweaking the existing coils).

The wisdom of the ancients warns against modulating variable frequency 
oscillators, and I believe with good reason.  I couldn't see why the 
same problems would occur when modulating a crystal-controlled 
oscillator, and in fact they don't.  I measured 200 hz of carrier shift 
under full modulation, which is going to be undetectable on any AM 
receiver.    And the circuit works well with the 3880 and 3885 crystals 
that are available for $2.55 each from 
http://www.expandedspectrumsystems.com/prod4.html     No reason the same 
would not be true for 160 meters (or 40, for that matter).

Give it a try and I think you'll be surprised.

73, Bob W9RAN