HW 16 info

[Ken Ketner]

W7EKB passed some very nice HW 16 tidbits on to me and with his
permission I post them on the heath list.

Subject: HW 16 mods
   Date: Wed, 30 May 2001 22:05:21 -0700
  From:  "Kenneth G. Gordon" <keng at moscow.com>
     To: Ken Ketner <ketner at arisbeassociates.com>


>  I get about 20 watts and chirpy on 15 meters, about 50 max on 80 and
> and seems less chirpy, but haven=92t checked any chirp on air, just
> through hearing the spot note on the RX.
        Solder a 100 to 220 pFd silver mica cap between the screen of the
oscillator tube and ground.You may need to experiment with the value to
get minimum chirp on 15. However, this will eliminate chirp on 15 with
crystals. If chirp on 15 is OK, the others will be fine.
> I think the 15 meter resonance
> probelm is fixed because I can get a peak with the TUNE cap on 15. But
> still the power seems low on 15.
        If you have spread the bottom turns of the plate tank coil and then
re-aligned it, you should get at least 30 watts output on 15. Check the
alignment
of the driver tube and neutralization of the final amp.
>  What mods would you suggest?
        Have you done the three resistor changes, two in the receiver section
and the third to make the sidetone a bit quieter? You may want to build
a shield across the crystal filter to better
isolate the input side from the output. Helps keep strong off-frequency
signals from sneaking through the filter.
        An excellent thing to do is install a Vectronics/MFJ CW audio filter
between the 1st and 2nd audio stages. Makes a world of difference! The
filter costs $19.95 and is worth every cent of it. Or you could connect
it between the audio output and headphones.
        A mod from Hints and Kinks is to add a dual diode clipper in the audio
circuit, usually externally. Helps with clicks in the headphones.
> I saw those listed on www.wa3rey. Has
> anyone ever tried to use the HW 16 RX vfo to run the TX?
        There was an article in QST magazine a LONG time ago that described a
mod to do that. However, it is not trivial. The VFO tunes "backwards"
for one thing. I.e. fully meshed tuning capacitor is highest received
frequency and vice versa. It really isnt worth the trouble.
> Also, I have a
> spare Heath VF-1. What are the mods to use it with HW 16?
        Easy. Disconnect the lead in the VF-1 that runs from pin 8 of the
power/keying cable connector to the place in the VF-1 that connects to
the cathode of the oscillator tube, or to the function switch (I can't
remember which it is). Lift the two grid leak resistors, a 2.2K and a
22K from where they are grounded right near the bandswitch. Mount a
two-lug-with-one-lug-grounded terminal strip under the screw
that is nearby. Connect the free ends of the two grid leak resistors to
the UN-grounded
lug. Solder a .01 mFd disk ceramic cap from the junction of the two
resistors to the grounded lug. Lastly, connect the wire that goes to pin
8 of the power connector that
you removed from the cathode of the oscillator tube to the junction of
the two resistors and the cap. Then plug it in to the HW-16s accessory
socket. If it is wired properly (!) that is all you should have to do.
The mode switch of the VF-1 must be in the "Operate" position in order
for the VF-1 to be keyed on. You won't have a "Spot" function unless you
add a switch to ground the two grid-leak resistors when you want to
"Spot". I never bothered with that. OR you could disconnect the lead on
the mode switch that goes to the cathode of the oscillator tube, then
ground the key jack connection on the back panel directly. Then connect
a wire from the junction of the two grid-leak resistors to the vacated
position on the mode switch. Then, when you put the VF-1's mode switch
in "Operate" it would be a "Spot" function instead.
> Many thanks for taking the time to read this.
        Sure. If you need a VF-1 manual and/or a printout of some of the mods
to
it, let me know. === Ken W7EKB

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