[amsat-bb] Re: satellite antenna photos oa4o

WILLIAMS MICHAEL k9qho6762 at sbcglobal.net
Sat Dec 8 16:55:21 PST 2012



After many years, I homebrewed polarity switching into my old 2 meter KLM 
antenna. The switching/matching system is made up of the matching coax, relay, 
printed circuit board (PCB), and the baluns.

Here are several options.

1. Try to save the old hardware.
2. Split the antennas. 
3. Set circular polarization permanent.
4. Rebuild the polarization switching using the original relay design. 
5. Rebuild the polarization switching using a coaxial relay design.
1. The 4/1 baluns seem to survive the weather relatively well. The damage is 
more severe to the matching coax, relay, and especially the PCB. If the PCB can 
be saved, then the relay cover can be removed and the relay inspected and 
powered. If a new relay and coax is considered, the matching coax is RG-59. The 
relay is a Guardian 1365PC-2C-12D priced at $56.00 from Allied Electronics. 

2. Each antenna is 50 ohms and can be used one at a time using a coax relay 
switching between verticle and horizontal, In today's satellite enviroment, 
switching between vertical and horizontal is a simple solution and a good 
option. Or forget the relay and use only one antenna

3. Make a matching harness (RG59) and set the circular polarization permanent 
either RH or LH. I used this method for many years with my KLM set LHCP. Since 
this method requires no relays or DC power out at the antenna, it can be built 
quickly and get you on 

the air while you are building the polarization switching system. When 
completed, you can change them out.
4. This requires a PCB to be made. I you decide on this option, contact me. I 
can help you. Trying to duplicate a manufacture's design especially KLM's PCB 
can invite problems. 

5. Some are using the Tohtsu CX-120 coaxial relay with success. It's cheaper 
than the Guardian relay priced at $35.00. I think a simple one sided PCB could 
be etched easily and the relay could be mounted near or between the dipole 
terminals. This would be much simpler thatn the two sided KLM PCB.
I hope this gives you some ideas. Please email me if I can help.
One last thing. If you are going to do this, mount all your hard work in a 
weather proof box. 

All the best from Indiana.
Mike, K9QHO

Message: 1
Date: Fri, 7 Dec 2012 09:32:33 -0500
From: Lizeth Norman <normanlizeth at gmail.com>
To: Mike Seguin N1JEZ <n1jez at burlingtontelecom.net>
Cc: amsat-bb at amsat.org
Subject: [amsat-bb] Re: satellite antenna photos oa4o
<CAJUhCTNHsL06JZYecKOP6cs8O_zpn7y3rK4OMRd+WoYa+_1ryA at mail.gmail.com>
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Bill, John and Mike,
I would love copies of the manuals. Please forward them on as I will
pass them along.
What era are these antennas?
The 70cm one tests good. The rest need work.
Has anyone done anything to rehab these?

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