[Amps] Relay Suggestions Please

[Jeff Blaine]

Steve,

I have been using the same relay that Jim mentions also.

There are about 50 of them spread out in my antenna system for this or that. 
My primary operation mode is RTTY contesting at the KW level.

And I've not had any failures in the 3 years except for the ones that I have 
hot switched - the failure mode in that case is a stuck contact (open or 
short).

I believe the Ameritron antenna switches now use this same relay.  And I 
think they all are built by Tyco divisions of one name or another now.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: Jim Garland
Sent: Friday, March 09, 2012 10:28 AM
To: amps at contesting.com
Subject: Re: [Amps] Relay Suggestions Please

Interesting comments in this thread. I checked a variety of PCB power relays
for my StationPro controller and finally settled on the TE Connectivity/P&B
model RTB14012F.  (Mouser part number 655-RTB14012F). Builders of my
StationPro kits have used approximately two thousand of these relays and
there are no reported failures of any sort (although one new relay had an
open coil). Some of my builders have run them at well over 3KW with no
problems, but I ain't naming names.

In my development work, I have tested them extensively at 2500W at 30 MHz
and below and they present no measurable impedance bump when installed in
the StationPro's remote relay unit. At 50MHz, their VSWR rises to about
1.2:1 and at 144MHz it approaches 2:1.

Another common relay choice for RF switching in the same package is the
Panasonic JW1FSN-DC12V (Mouser p/n 769-JW1FSN-DC12V), which is used in some
commercial RF switches. This relay, although it easily handles the US legal
limit below 30 MHz, has a completely different internal design than the
RTB14012F, with longer internal leads and significantly smaller contacts,
and for those reasons I did not select it. On the other hand, in contrast to
the RTB14012F, the Panasonic relay has its coil mounted vertically, so that
there is less mutual inductance coupling between the coil and contacts, and
this results in better VHF performance than the RTB14012F. At 144MHz, for
example, the VSWR is only about 1.5:1, so this relay is preferred at those
frequencies. Below 30MHz, the RTB14012F is the better choice.

One caveat. These relays are not hot-switched in my application, so I can't
attest to their performance in that regard.

73,
Jim Garland W8ZR





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