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Re: [TowerTalk] Antenna Relay -

To: <>, <>
Subject: Re: [TowerTalk] Antenna Relay -
From: "Roger (K8RI)" <>
Date: Sat, 12 May 2007 13:36:47 -0400
List-post: <>
All very good points which I'm not going to snip: Just this additional 

These are almost certainly "stock" relays from some one and are most likely 
available from the regular suppliers with one likely candidate being Mouser. 
IF some one can find those relays or equivelants they will have a good 
start, but as you say, how they are mounted and what is used for leads can 
make a big difference in the upper limit to the useful frequency range as 
well as impedance bumps.


Roger (K8RI)

> 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
>, and those on Jays web
>, 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"  <>
> Subject:What relay do Ameritron and Array Solutions  use in their coax
> switches?
> To: "W7CE" <>, _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:
> 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" <>
> To: <>
> 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
>> Thanks & 73,
>> Clay   W7CE
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