As many of you know, I have been compiling a list of stations
and or operators who are willing to take a new comer to
contesting under their wings and show them the ropes. The
will be published monthly in my column in the new magazine
CQ Contest. Here is the latest version of the registry. Any
stations in the NY/NJ area want to get on the list?
Again I want to emphasize, this magazine is going to be
World Wide in scope, not just USA/NA, hence so is the
registry.
The response from the USA has been great! There are a few
DX stations listed, but I'd like to see more, along with more
from Canada.
K1KP Andover, MA
K1VR Lincoln, MA
K5ZD/1 Wocester, MA
KY1H Western MA
W1FY Framingham, MA
K1TR Southern NH
KB1GW Avon, CT
N1QVE CT
KE3Q Bowie, MD
ND3F Baltimore, MD
W3GG Derwood, MD
KA4RRU Northern VA
AA4NC Raleigh, NC
K1ZX/4 Tampa, FL
W4NVU Miami, FL
KM9P/4 Atlanta, GA
AB4RX Louisvlle, KY
WB4FLB Bowling Green, KY
AC5CT Dallas, TX
WX0B/5 Dallas, TX
KS1G/5 Dallas, TX
WB5VZL Austin, TX
NI6T Los Gatos, CA
W8AKS/6 Tehachapo, CA
K6XO/7 Salt Lake City, UT
K7FR Eastern WA
N0AX/7 Seattle, WA
N6TR/7 Portland, OR
N7UJJ Phoenix, AZ
W8FN SouthWest OH
W8FJ Norristown, PA
KF9PL Central IL
K9ZO Central IL
KO9Y Indainapolis, IN
K9SD/0 St Louis MO
K4VX/0 Hannibal, MO
KM0L Kansas City, MO
NX0I Kansas City, MO
WA0PUJ Northern MN
N2IC/0 Denver, CO
W0AIH Eau Claire, WI
WD0T Pierre, SD
Canada
VE6SH
VE6JY
DX
F5VCO (TM1C....)
ON4UN (OT5T....)
OH6YF
PA3ERC (PA6WPX and PI4COM)
S56A
XE2AC
There are quite a few contests coming up in the next month,
like Sweepstakes SSB, CQWW CW, 160 CW and the 10 meter
contest, along with the NAQPs in January. Let's see some of
the newer people take advantage of this opportunity. Contact
me and I'll get you in touch with the appropriate person.
And as usual, anyone interested in being added to the list,
email me directly and I'll take care of it. (And if there are
any errors, let me know.)
CU all from 4M5X in CQWW CW!
Paul WX9E
>From Fred Hopengarten" <k1vr@k1vr.jjm.com Thu Nov 16 03:27:02 1995
From: Fred Hopengarten" <k1vr@k1vr.jjm.com (Fred Hopengarten)
Subject: Second Radio Protection
Message-ID: <30aaaf89.k1vr@k1vr.jjm.com>
On Oct 22, 1994, AD1C (reisert@tiac.com) started a receiver
protection thread by writing:
> I need help! W1JR has a bad problem with his IC765. When
> he has the beverage switched in on 80 meters, his transmit
> power drops to nothing. It sounds like the Beverage is
> being overloaded, and it's coupling in to the radio,
> shutting down the transmitter somehow.
> Anyone solved this problem?
The replies:
We had this same problem at KS9K last year, on 160M.
Our West TX antenna was too close to our West/East beverage
(two-wire). It would cause the radio to turn off and on
rapidly, and to make funny noises. (Listening on the NE/SW
beverage, or TXing on the East TX antenna was fine.)
It was obviously a TX coupling into the RX problem.
What I ended up doing was putting a small relay in the
beverage switch box that was keyed off of the PTT. When you
would key up the radio, the relay would open up the RX line
and put a 50 ohm load into the RX. I don't know if the 50
ohm load is necessary, but it sounded like a good
idea.
Everything was solved.
Chad Kurszewski, WE9V Chad_Kurszewski@csg.mot.com
The easy way to prevent excessive RF from getting into a
receiver is to use one or two reed relays that are keyed
along with the radio. Reed relays will operate in less then
a millisecond and there will be essentially no loss in the
received signal. With a SPDT relay the rcvr input can be
switched from the Beverage to ground on transmit.
George, W2VJN. gcutso@mcimail.com
Here is a proven method for protecting receivers:
Use a .063 Amp (1/16 amp) fast blow fuse in line with the
receiver. Littlefuse number 251.062; Digi-Key number F820-
ND. They look like a green resistor. I solder them
in between an RCA male plug and RCA female socket. This
little unit gets plugged into the receive line, downstream
from the receive bandpass filter, right at the receiver
input jack on the 765/735. The fuses are available from
Radio Shack or Digi-Key.
Make a few extra up before the test, for quick replacements!
So far, I have blown three fuses and *ZERO* receivers.
Tony, K1KP fisher@hp-and.an.hp.com
Replying to a query about protection at multi-multi contest
station KY1H, the owner and Chief Engineer himself wrote:
No, I have no fuses or bulbs in the lines. With about 30db
of attenuation outside the desired band, I shouldn't need
it. I can only have one tx on a band right now. Each tx
position has bandpass tx filters and stubs, so you cannot
accidently tx on the wrong band and get through the rx
filters of another station. If/when I start putting second
transmitters on bands, I will probably have to rethink that
problem.
Dave KY1H Robbins@guid2.dnet.ge.com
> I need help! W1JR has a bad problem with his IC765. When
> he has the beverage switched in on 80 meters, his transmit
> power drops to nothing. It sounds like the Beverage is
> being overloaded, and it's coupling in to the radio,
> shutting down the transmitter somehow.
> Anyone solved this problem?
> Thanks - Jim AD1C
I had something similar with mine. When I would transmit,
so much RF would come back in the Beverage input that the
lights in the radio would go off. It looked as bad as you
can imagine.
I ended up building a box that is tied to the transmit relay
out of the IC765. When transmitting, it removes the
Beverage from the radio. Problem was solved.
Built the whole thing from Radio Shack parts in the
afternoon before CQWW CW last year. Good luck!
Randy Thompson, K5ZD k5zd@iconics.com
By the way, those little blue Radio Shack relays will switch
at QSK speeds, if you drive the coils with a 50 V source and
a series resistor.
Scott K9MA sellington@ssec.wisc.edu
Randy is right on! The reason you'll often have unwanted
coupling problems on 160M is because the traditional choking
and bypassing values of components aren't sufficient for
that low a frequency. I recommend grounding the beverage to
your ground system via a relay during transmit. It then
contributes to your transmitted signal as a long radial, yet
does not cause any unwanted coupling.
I've had the coupled signal get into my ALC and reduce
output power to nearly zero, into the power supply and cause
a terrible hum, and into the audio and cause terrible
squeals. I was able to solve all of these problems with
extensive bypassing, but grounding the receive antenna is
the simplest and best remedy. I'm presently using an
unterminated beverage along my fenceline, and it becomes my
ONLY radial during transmit. I don't have a crushing 160M
signal, but I do get out!
Paul, KB8N
K1VR Commentary
Someone has asked about using "grain of wheat" lightbulbs in
the receive line, and another person has asked about using
#47 (bayonet mount) light bulbs. But I haven't seen any e-
mail on those questions.
So it seems that there are several ways to protect a
transceiver front end:
(1) Light bulbs
(a) grain of wheat, or
(b) #47
(2) Grounding with a relay, or other mysterious parts
purchased by K5ZD just before the contest. [Randy: Want to
give us the parts list and construction tips?]
(3) Bandpass filtering and stubs
(4) Fuses
Discussion:
(1) Light bulbs
Anyone have tips on mounting one so that the lightbulb
can be replaced easily in the middle of a contest?
Principal advantage: May offer possibility of listening on
the same band you transmit on. Question in my mind: Will a
lightbulb blow up before your front end caves in?
(2) Grounding by relay
Principal advantage: Really good protection, fast
switching possible. Questions in my mind: Does this solve
the two-radio problem of protecting your second radio, which
you may wish to tune while calling CQ on the first radio?
It may ground your first radio, but do you want to ground
your second radio?
(3) Bandpass filtering and stubs
Solves the different band problem, but not effective on
second harmonics, nor designed to handle the "same band"
problem.
(4) Fuses
Principal advantage: Protects, by failing. Question
on my mind: If blowing up is routine, is it too much of an
interference to the goal of racking up points? You lose
your run frequency while changing fuses.
Question to the Contest Reflector:
How would you protect your _second_ radio?
--
Fred Hopengarten K1VR
Six Willarch Road * Lincoln, MA 01773-5105
home + office telephone: 617/259-0088 (FAX on demand)
internet: k1vr@k1vr.jjm.com
"Big antennas, high in the sky, are better
than small ones, low."
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