[ARC5] Heathkit Folks: Early "Heath Company" Aircraft Transmitter.

[Robert Nickels]

On 11/26/2011 5:24 AM, David Stinson wrote:
> I've recently got this little gem working, though it was pretty much operational from the start:
Congrats Dave!     I know where there is one like it - or almost like it 
- and that's on my shelf, waiting for me to noodle it out.   However 
mine is market "HT-4", and I'm really curious now to know what the 
differences in your HT-4B3 are.

I posted some pics here:  
http://smg.photobucket.com/albums/v652/ranickel/Heath%20HT-4/

Also, while there's clearly a dot in front of your "6", there isn't on 
mine.   Could this mean yours was a "QRP version for battery power 
operation"?   My HT-4 uses a 6J5 oscillator driving a pair of 6V6 
finals, so 6 watts output sounds about right, assuming a 300 volt B+ 
supply   The modulator is another 6V6, with the typical carbon mic - a 
typical design for low-power AM mobile ham rigs of the era.   But that 
would be overkill for only 600 mw.

I've never found a schematic but it's pretty simple, although I'd 
appreciate your power connections just to compare.  Also, are you using 
the trailing or fixed antenna position (not sure what the difference 
is).    I've read that there was an "HR4" receiver but can't confirm 
that, and suspect if there is it would be a LF receiver, as the standard 
back then was for the a/c to transmit on HF and listen to the tower over 
the LF beacon transmitter.  There was also  a brief period where MF and 
VHF were used, before everything moved to the modern VHF band.

73, Bob W9RAN