Ron
Depending upon what is available to you, try more capacitors in parallel
with .25uf, or use a bigger cap, maybe .47 or .5 uf. If you have a scope,
measure the risetime on the clicks,
then select RC or RL combinations that will be longer than the rise time 73
Ron K3MIY
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]On Behalf Of Ron
Sent: Sunday, January 22, 2006 6:15 PM
To: TenTecReflector
Subject: [TenTec] OT: Key Clicks HW-16
I wrote earlier looking for technical info and did not get a reply, so I'll
send this and see what happens. It is "off topic" but then so is much of
what I read here... :)
A while back, there was a discussion on hard keying and key clicks with the
ORION set incorrectly and about Yaesu 200 watt transceivers etc. I used my
old Heathkit HW-16 as an example of a chirpy transmitter with key clicks.
Anyway, that was what got me interested and I replaced the filter caps in
the transmitter B+ lines and the chirp quit, but the hard keying was even
more accentuated without the oscillator pulling to soften them. So out of
the junk box came a 150 ohm resistor, a .25mf capacitor and a .670 UH choke
out of an old computer monitor. Resistor and capacitor in series to ground
from the -150 V keyed bias line and the choke in series with the keyed line.
(I have no idea what values would be right) But this circuit seems to have
softened the keying.
Here are my current readings:
Full power into a 50 ohm load @7.117 MHz (HW-16)
Orion II set at no ATTN
8 inch long jumper for an antenna
RF gain set at 100
AGC set slow
100 Hz CW filter cut in on the ORION II
Keying the HW-16 steady dits at about 20 wpm
Center frequency showing a 20 over S9 peak on the ORION II
Tuning the Orion for testing:
minus 1KHz shows S3
minus 2KHz shows S1
minus 3KHz shows no movement
-17 KHz no longer audible on the receiver
plus 1KHz shows S1
plus 2KHz shows no movement
plus 13 KHz no longer audible on the receiver
Prior to the filter, I had AM key clicks S3 to S5 up and down the band for
100 KHz in each direction. So given where this rig started from, this is
quite impressive to me. The 670 UH choke is about 1 inch long and 3/4" wide
on a dumbbell looking ferrite core. If I knew what I was doing, I could
probably wind 5 or 6 times the original wire length on the core and make the
value of inductance increase proportionately. The current draw is minimal in
this bias circuit so I am thinking very fine gauge magnet wire should work
fine.
So now after this long dissertation, does anyone have ideas about how to
further improve the keying on this old rig? In the original thread, I was
told to please leave it "on the top shelf", but where is the fun in that?
Ron KA7U
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