I cut my teeth on relays so I understand SP, DT, NO, NC, lathing etc, etc. I
don't think there is anything parasitic involved, by parasitic do you mean
the capacitive coupling between the moving contacts, stationary contacts and
the electromagnet? Some relays have more capacitive coupling between
contacts and between contacts and electromagnet/armature than others and in
RF work less coupling is normally better. When replacing relays in RF
circuits it is always best to try and maintain the parameters of the
original relay since just maybe the design engineer knew what he/she was
doing. 73, Ron W8RJL
----- Original Message -----
From: "Jim Lux" <jimlux@earthlink.net>
To: "Ron W8RJL" <youngron@verizon.net>
Cc: "Tower and HF antenna construction topics." <towertalk@contesting.com>
Sent: Monday, September 27, 2010 11:50 PM
Subject: Re: [TowerTalk] X99KP 12VDC RELAY FOR AMERITRON REMOTE ANTENNA
SWITCHES
> And just how do you think they do a "double make" contact? :)
>
> Bridge the two armature contacts on a dpdt or dpst relay and you get a
> double make spdt or spst.
>
> On Sep 27, 2010, at 8:39 PM, "Ron W8RJL" <youngron@verizon.net> wrote:
>
>> For anyone who might be confused by the armature and parasitic verbage
>> here
>> is what Allan Bradley has to say about Form X relays:
>>
>>
>> A Form X contact arrangement is one which has single-pole, single-throw,
>> normally open double-make contacts. The function of this arrangement is
>> to
>> close a circuit when actuated.
>>
>> Forget about parasitics and armatures. It is just a contact
>> configuration.
>>
>> 73,
>> Ron W8RJL
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Jim Lux" <jimlux@earthlink.net>
>> To: <richard@karlquist.com>
>> Cc: "Van K7VS" <wa7fab@cdsnet.net>; <towertalk@contesting.com>
>> Sent: Monday, September 27, 2010 11:20 PM
>> Subject: Re: [TowerTalk] X99KP 12VDC RELAY FOR AMERITRON REMOTE ANTENNA
>> SWITCHES
>>
>>
>>> W8JI mentioned tat they have form X contacts. That is the two contacts
>>> on
>>> the armature are bridged permanently, and there's no separate connection
>>> to the armature. Sort of like a rf transfer switch. Reduces parasitic
>>> c
>>> from armature to coil, etc.
>>>
>>> On Sep 27, 2010, at 10:55 AM, "Rick Karlquist" <richard@karlquist.com>
>>> wrote:
>>>
>>>> Van K7VS wrote:
>>>>> THE X99KP 12VDC RSCo. SPDT RELAYS ARE MANUFACTURED BY A COMPANY IN
>>>>> CHICAGO
>>>>
>>>> The company is probably Magnecraft, in my old home town of
>>>> Des Plaines, IL, a suburb of Chicago. They show some
>>>> nice off the shelf relays for antennas. Maybe the
>>>> Ameritron has gold plated contacts as a special. That's
>>>> the only thing I can think of where the OTS relays
>>>> are less than optimum.
>>>>
>>>> Rick N6RK
>>>>
>>>> _______________________________________________
>>>>
>>>>
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>>>
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>>
>>
>> _______________________________________________
>>
>>
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