[Heathkit] Hw-16 neon bulb and keying.

[Kenneth G. Gordon]

On 19 Feb 2007 at 11:23, Tom Chesek wrote:

> That specific bulb is Heath part number 412-34.  The 1984 Heath master
> parts list shows that part as a neon lamp at 62.0 volts, .40 ma,
> #3AGB. That master list also shows part number 412-11 which is an NE-2
> as 59.0 volts, .30 ma.  Having said that I suspect that anything close
> works fine.

As you say, it is part of the relaxation oscillator for the sidetone, and 
practically any neon bulb will work. When mine broke off at the bulb, I 
got a "generic" one at RatShack that worked fine.

> Rev Don's modification seems more appealing unless you
> want an "original".

The main reason for the existence of the sidetone oscillator is that 
when you use the HW-16 in crystal-controlled mode, your transmitter 
frequency may be quite different from the frequency of the received 
station's. In the days when many stations were crystal controlled, it was 
extremely common for this "cross-band" type of work to occur. Using 
Heathkit's original circuit provides an independent sidetone.

However, since 99 and 44/100% of hams now-a-days won't even 
ATTEMPT to listen or tune for anyone who is not exactly zero-beat with 
their transmitted frequency, Rev. Don's mod would be valuable.

I use my HW-16/VF-1 combo as my main station CW rig and like it very 
much. The only thing I find annoying about it is that darned very sharp 
and loud "click" or "snap" at key-down. I have not yet found a way to 
quiet that. I understand that some HW-16s don't exhibit that sort of 
behaviour, but both of mine do.

Ken Gordon W7EKB