Towertalk
[Top] [All Lists]

RE: [TowerTalk] Help need Vacuum Relay Isolation 1.8 to 30

To: "OM7ZZ, Jozef Urban" <om7zz@stonline.sk>,towertalk@contesting.com
Subject: RE: [TowerTalk] Help need Vacuum Relay Isolation 1.8 to 30
From: Jim Lux <jimlux@earthlink.net>
Date: Wed, 05 Jan 2005 15:44:43 -0800
List-post: <mailto:towertalk@contesting.com>
At 02:38 PM 1/5/2005, OM7ZZ, Jozef Urban wrote:
We're builded 10 ANT / 2 Radio switch with Gigavac G2SP relays. On each ANT port are three of them used.
Achieved -60dB isolations on adjacent ANT ports and more than -70dB on non adjacent ports.
When both radios would like to select the same antenna, isolation is still around -68dB.
All mentioned isolations was measured at 28MHz.


Some fotos and measurements are here:
www.microham.com/Custom/DT/doubleten1.jpg
www.microham.com/Custom/DT/doubleten2.jpg
Insertion loss
www.microham.com/Custom/DT/insertion.jpg
SWR
www.microham.com/Custom/DT/swr.jpg
Isolations same ANT port
www.microham.com/Custom/DT/isolation1.jpg
Isolations adjacent ANT ports
www.microham.com/Custom/DT/isolation2.jpg
Isolations non-adjacent ANT ports
www.microham.com/Custom/DT/isolation3.jpg

73 Jozef OM7ZZ

Looks real nice. I assume you're using the little blue relays to switch the current for the RF relay coils?


It looks like you have 3 SPDT relays on each antenna port. The first relay connects the antenna to one of two other relays. The side you're connecting to is switched to the radio. The "other side" is switched to ground?

So, the isolation from one radio to another would be essentially two relays worth.


Is the copper strip "star" in the middle designed as a 50 ohm microstripline? Or is it just a convenient size?


Jim, W6RMK


_______________________________________________


See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>