[Heath] HW-16 transceiver questions

[Kenneth G. Gordon]

On 7 Mar 2014 at 21:58, John Klingelhoeffer wrote:

> A couple of quick questions to the group regarding the HW-16 CW 
> transceiver I am currently refurbishing. 
> 
> 1) I notice this has a circuit breaker in the mains primary instead of 
> fuses. Seems like this is unusual for a Heathkit. This one is working 
> fine, but I'm wondering if there have been any electrical safety problems 
> with that approach over the years the HW-16 has been in the wild?

Never.

> (note: 
> I've already changed to a 3-wire grounding AC mains cord and plug.)

Good.

> 2) I'd have to believe that the transmitter met the FCC requirements for 
> harmonic and spurious emissions at the time it was designed and 
> manufactured, but has anyone taken measurements on an HW-16 'lately' to 
> see if it meets current requirements?

No. However, there is at least one modification out there which allows 
adjustment of power output down to the 5 watt level. I have read a 
statement by someone who, apparently, knows, that at lower-than-designed-
for power output, due to the change in final amp impedance, the harmonic 
suppression is worse, and at that point, probably does not meet FCC 
requirements.

I run mine through a Hi-Q antenna coupler so I have never worried about 
it.
 
> 3) Has anyone come up with an AGC circuit for the HW-16 that works 
> without adversely affecting the very good full-break-in QSK keying 
> functionality? Running with no AGC is a real pain both operationally and 
> on the ears.

Yes. Two, in fact. One by Hatch originally designed for the R-390 
published in Electric Radio Magazine, and 2) one designed for one of the 
HBR receivers, easily adaptable to the HW-16 (in fact, one HW-16 user 
recently installed that). Both work very well, but the Hatch circuit is 
simpler, and in my opinion, works better.
 
> 4) Has anyone come up with a more pleasing sidetone oscillator that is 
> simple to integrate into the current circuity (phase-shift oscillator or 
> something) rather than the somewhat raucous and raspy neon bulb 
> relaxation oscillator? I'd sure like an internal sidetone option with a 
> more pleasing tone.  I can adjust the amplitude of the current 
> oscillator, but the waveform is just downright lousy. 

Unless you are using crystals all the time and work cross-band, there is 
really no need for such a sidetone oscillator. I eliminated my ugly neon 
job completely, reduced the value of Q-1's biasing resistor in order to 
keep it turned on a bit with the key down, and use the transmitter itself 
as my sidetone. I much prefer this.

BTW, in the last ARRL DX Contest, I worked 30 some DX stations on 20 with 
the HW-16 at 50 watts output. Great fun. I used a refurbished WRL-755A 
VFO modified for blocked-grid keying.

Ken W7EKB