With regard to choice of conventional "clapper" type relay to use for RF
circuits note there are several considerations to be evaluated. Power
handling,
RF Voltages/Currents and Frequency. Below 30 mHz most of the popular relays
available will work with a little care in dressing the leads to the
contacts, and PCB mounted relays usually solve that issue.
The material separating the leaf springs may determine the "voltage" rating,
and the leafs and contact buttons are a factor in current handling. (Power).
Frequency factors are more to do with the physical design and dimensions of
the leafs and wires that connect the leaf springs to it termination. I
looking at the relays used in the Ameritron antenna switch
www.w7ce.com/relay.html, and those on Jays web
http://www.arraysolutions.com/Products/ratpak.htm#relay, and most relays
offered, there is one very big difference that would be a
factor in upper frequency range use and maybe power handling.
Note the web connecting the two leaf springs together. This provides a very
low inductance path for RF currents to flow. Since this relay is a DPDT it
permits paralleling the contacts for high current handling. Also note the
relays shown on Jay's site do not appear to be PCB mounting type which may add
more "lead" inductance when making connections.
Ratings are part of the selection criteria, but also how it is mounted and
constructed may be more important depending on the end use. I don't think the
relays from Jay will have the high frequency range of the Ameritron relays.
I would try going to MFJ and seeing if they will sell you relays as
replacement parts, somebody has to make repairs and do replacement.
Norm W4QN
==========================================
From: "Tom McAlee" <tom@klient.com>
Subject:What relay do Ameritron and Array Solutions use in their coax
switches?
To: "W7CE" <w7ce@curtiss.net>, _towertalk@contesting.com_
(mailto:towertalk@contesting.com)
I don't know the manufacturer. But, if your goal is to obtain some, you can
buy those relays from Array Solutions:
http://www.arraysolutions.com/Products/ratpak.htm#relay
Scroll to the bottom. You'll see he sells the relays individually for $45
each... same relays used in the RatPak, SixPak, etc.
If you really just want to know who makes them, perhaps if you call or email
Jay he will tell you.
73,
Tom, NI1N
----- Original Message -----
From: "W7CE" <w7ce@curtiss.net>
To: <towertalk@contesting.com>
Sent: Friday, May 11, 2007 9:24 PM
Subject: [TowerTalk] What relay do Ameritron and Array Solutions use in
their
coax switches?
>I am designing a custom coax relay. I own a couple of Ameritron RCS-8V
> switches and am pretty happy with them, especially since they are rated to
> 250+ MHz. I recently looked inside an Array Solutions Ratpak and noticed
> that it uses exactly the same relay as the Ameritron. I've been trying to
> figure out who is the manufacturer of this particular relay and after much
> time with Google have hit a dead end. Both switches use a form X
> (shorting bar mounted on the two arms at the contacts) SPDT, 12V
open-frame relay
> with the following marking: X99KP 12VDC RSCO. It appears the X99KP is
the
> part number and RSCO is the vendor name or code. Does anyone know who
makes
> this relay? You can see a picture of it at www.w7ce.com/relay.html.
>
> Thanks & 73,
> Clay W7CE
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