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   Home   Help Search  
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Author Topic: Johnson Matchbox Relay  (Read 2131 times)
WA0RXR
Member

Posts: 12




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« on: February 19, 2008, 05:24:33 PM »

I have been given a Johnson 275-watt Matchbox from the estate of an Elmer. I have an open-wire-fed doublet that would be a great fit for this unit. My question is: Do I need to do something to the built-in T/R relay circuit since I am using a transceiver? Can I just leave it un-energized or do I need to bypass it somehow?

Any advice is greatly appreciated!

Mark   WA0RXR
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KA5N
Member

Posts: 4380




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« Reply #1 on: February 19, 2008, 06:09:53 PM »

With a transceiver, the relay should always be in the "transmit" position.  Lots of people just jam it closed, or you can rewire it or bypass it.  I wouldn't leave it energized as that would be a waste of AC plus the relay might overheat or otherwise get flaky.
Allen
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W5RKL
Member

Posts: 1041




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« Reply #2 on: February 22, 2008, 10:21:51 AM »


If you are going to use the matchbox all of the time,
simply bypass the relay. This is easily done by
performing the following steps.

1. Remove the wire between the "input" SO-239 and
the relay.

2. Remove L1's wire from the relay.

3. Connect L1's wire you just removed in step 2
and connect it to the "input" SO-239. Do not
disconnect or mess with L1's ground connection.

4. Relay is now bypassed.

If you must use extra wire to accomplish the bypass,
make sure the wire is the same size and is solid,
not stranded.

An SWR meter placed between the transmitter and
the matchbox is required unless you're using the
Johnson Directional Coupler (SWR meter).

If you don't have the manual for the Matchbox you
can download it at the following website.

http://bama.edebris.com/manuals/johnson/matchbox/

Click on the the matchbox.pdf link.

73
Mike
W5RKL
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W8ZNX
Member

Posts: 1




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« Reply #3 on: February 25, 2008, 12:48:13 AM »

this has worked for me
for over 25 years

make sure relay contacts are clean

then shove a match book cover
in to relay coil side
forcing contacts closed

close tuner back up

cheap simple works great

and if you want  to go to
boat anchor style operation
with transmitter / reciver

you can still use the relay
just remove the match book cover

mac
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