Dave,
Thanks for getting the 222 Activity Night going! It's a great idea. I
love 222! Unfortunately, life has intervened every time. I've been
having a pretty tough time this past year or so, and by 7 PM I am either
already sleeping or so utterly exhausted I don't care about anything but
going to sleep. I hate this! I am doing everything possible to get
better regulated so I can be functional in the evenings!
When I get my 6 and 2 meter antennas fixed I will be scratching around 2
meters in the mornings. Perhaps I can coax a few to try 222.
I do things a little differently with my HV supply. There are two DPST
normally open relays with 40A contacts and 24 VDC coils in the PS. One
of them serves as the power switch in the 230VAC line. Its coil goes to
a connector which has a cable running to the RF deck. In the RF deck is
the 24VDC supply so the remotely located HVPS (in a corner behind a 6
foot rack full of stuff) can be controlled from there. The other relay
has a big power resistor across its contacts for the current limiter.
This relay coil goes to a comparator using either a LM741 or LM311, I
forget which! The comparator gets 24VDC from the same place as the power
relay but has a RC time constant circuit on its input, with a trimmer
potentiometer to adjust the time delay. The delay between the main power
relay being energized and energizing of this second relay to short out
the resistor in the 230VAC line is thereby adjustable. I was initially a
little concerned about reliability but I have been using this system now
for 20 years without one single glitch. The step start relay clicks in
with a nice crisp 'clunk' as opposed to the bit of a growl I experienced
in the past with 115VAC or 230VAC coil relays trying to pull in as the
voltage on their coil ramped up. There is a small relay on the
comparator circuit board to control the big relay. Some would call this
overly complicated. I suppose it does violate the KISS principle, but so
far I haven't had cause to regret it.
I used the same step start circuit in the unregulated 50V 25A supply for
my 2200 meter amplifier, which has 94,000 uF of filter capacitance.
73,
Paul N1BUG
On 5/27/21 3:18 PM, David Olean wrote:
It has been about a month since we started the 222 activity nights. It
is going. quite well in some areas. Not sure about other areas. It is a
big country after all! I am not a member of many VHF reflectors, so
have only been pushing the idea to The Northeast area, VHF Contesting,
and the 222 activity group. Hopefully, the word is being spread to other
areas.
In my area, there is a pretty good group of dedicated people who try to
get on each Tuesday night. Of course, life can always get in the way,
but, for the most part, a good group shows up most Tuesdays. Some calls
heard often include: WW2Y, KO4YC, VA3ELE, VE3ZV, VE3DS, WZ1V, N1SV,
K1PXE, N3RG, KA2LIM, K2AEP, and W9KXI among a few others! Quite a list
and it sure is fun seeing who you can work and say hello to.
This last Tuesday, May 25, was quite good generally, with warmer air on
average causing local signals to rise. The real long haul contacts still
can be troublesome, with little or no enhancement. I listen to the
K1IIG/B beacon and it seems to be stronger of late. Signals from 500
mile distances do not show much change however. The good news is that
500 mile contacts are being made on CW. Contacts in the range of
450-525 miles included VE3DS, VE3ZV, VA3ELE, and KO4YC.
I puttered around with my HV supply for the 222 amplifier. My step start
died due to builder error. I mistakenly used a 115 volt coil relay and
put it across 230 volts AC. I found another relay with a 115 volt coil,
but could not get it to work properly. Part of the problem was caused by
having a Variac in the primary. Once I drew out the circuit I saw my
problem, and tried to put some series resistance in the relay coil ckt
and put it across the 230 volt line. (not from one side to neutral) The
problem is that the relay draws different currents while it is trying to
pull in, and then when it is fully energized. I got it to pull in, but
then the current dropped and the voltage soared to 170 volts. This would
eventually cause another smoke event, so I abandoned that idea. My
solution was to find a 230 volt coil relay. Another solution would be a
230 to 115 volt step down xfmr. VE2XX uses varistors. That sounds good,
but my surge is especially severe, since I am using 12 X 2000MFD 550
volt electrolytic caps. Being a capacitor input supply with very high
peak currents, I wanted to keep any stray resistance away from in front
of those capacitors! It is 166 MFD! Power supply regulation under load
is a problem.
I did not get a chance to try any impossible contacts this time. The
distances between 450 and 650 miles would be fun to try. We just need
activity in the right places, and have gear that is capable of some long
haul DX. Maybe some increased activity on 222 MHz might convince some
hams to get active and / or upgrade their setups? 222 can be a
fantastic band, but I don't need to tell you all about that! CU all
next week.
73
Dave K1WHS
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