[Heath] HW-16 transceiver questions

Robert Groh rgroh at swbell.net
Mon Mar 10 12:17:35 EDT 2014

Ken,  I would love a copy of your mod sheet.  You might also stick a copy in the Files section on the Heath Yahoo group.

On your 'key click' question, I would suggest that you look carefully at what the various caps in the audio stage are doing during the T and R phases.  When I was working on the design of the SS-9000, I spent a lot of time pursuing similar problems.  Basically the various caps in and around the audio (e.g. coupling caps between stages) take a slightly different voltage levels when in T and in R.  Then when you shift between T and R, you cause a small (or large) voltage shift across the cap and that change propagates through the audio chain and ... bam!  Your ears get punched. Usually lots of low frequency gain in the audio so it doesn't take much. 

This problem is not at all uncommon - the SB-104 had a nasty case of 'key thump' that would, if you were using headphones, give you a major headache!!  I did a couple of things in the SS-9000 to mitigate that - mainly juggling RC time constants and setting up things so you didn't have a voltage shift on either side of caps.

Anyways I suggest you look around there.  Sounds like you have a solid program of debugging so keep 'er going!!

Bob Groh, WA2CKY
'Heathkit Engineering, 1977 to 1981'  and a Heathkit fan forever!!

 From: Kenneth G. Gordon <kgordon2006 at frontier.com>
To: Guy Giacopuzzi <gggdds at js-net.com>; heath at puck.nether.net 
Sent: Sunday, March 9, 2014 1:57 PM
Subject: Re: [Heath] HW-16 transceiver questions

On 9 Mar 2014 at 9:32, Guy Giacopuzzi wrote:

> If you find an answer to #4, I'm interested...

As I mentioned, I just eliminate that cursed raucous neon piece of junk and go 
with listening to my transmitter output directly by "adjusting" R-49, Q-1's 
biasing resistor, to allow the signal from the transmitter to be loud enough to 
use as a sidetone. For my uses, this has been very useful. Replacing R-49 with 
a small pot would make level adjustment very easy.

However, installing a phase-shifting type of audio oscillator shouldn't be all 
that difficult. The so-called "Twin-T" type is easy to build and works well. 
I'll go to work on that as soon as I can and will let the forum know about it 
when/if I accomplish anything worthwhile.

> Somewhere on the internet is a major mod of the 16', converting it to a 
> full tranceiver; I seem to remember an agc mod in this...

Yes. However, over on the forum dedicated to the HW-16, one of the subscribers 
there spent considerable time and effort to install and test this mod and found 
several problems with it, making it, apparently, much less than suitable for 
modern spurious emission issues. He removed it.

FYI, I have an extensive list of many mods available for the HW-16, culled from 
many sources over the years, all compiled in one paper, with references. I can 
send either a PDF or an MS-Word file of that to those interested.

One aspect of the HW-16's QSK method has been a constant problem for me: it is 
extremely "clicky" in my case, making it very fatiguing listen to for very 

If ANYONE could suggest a solution to this issue, I would be VERY glad to have 
it. Everything I have tried so far has not succeeded in fixing it.

I DID manage to track down where this clicking is coming from though, by 
pulling every receiver tube, in order from the RF amp tube to the audio output 
tube. Removing tube after tube toward the audio output made zero difference in 
loudness or characteristics of the horrendously loud clicks.

For reasons which I can not figure out yet, or what to do about it, ALL the 
clicking is coming directly from the audio output stage!

Although this is a new one on me, I really wish I could get it figured out and 



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