[Antennas] 6 or 8 Position Coaxial Switch
A10382
[email protected]
2002年7月24日 18:02:37 -0400
Hi Ed,
I don't think there was any mention of the rig or other antenna system
details in this thread.
One concern (it was one of mine) when using coax switched is the use of
antenna mounted amps, pre-amps, or transverters IF they're powered via the
coax. My Yaesu FT-847 provides 12V on the coax for mast mounted pre-amps
and transverters. You do need to be careful not to 'ground' the rig's
antenna output - it fries the 12V antenna power circuit. I would have
designed this a bit different - i.e.; a resistive load in series, inside the
radio, to keep some load on the output transistor.
Although looking at the mechanical switches and applying some logic would
indicate there should not be a problem, I have not seen enough switches to
provide any general advice.
Some switches have a position that grounds the antenna outputs. Neither
Alpha Delta nor Daiwa could guarantee that the center position would never
be grounded -o-r shorted long enough when the protection gas tube 'fires' to
protect the rig's 12V coax circuit.
73
Frank
._._.
----- Original Message -----
From: "Mike Gilchrist" <[email protected]>
To: "Ed Tanton" <[email protected]>; "Graham Dacombe" <[email protected]>;
<[email protected]>
Sent: Wednesday, July 24, 2002 6:32 AM
Subject: Re: [Antennas] 6 or 8 Position Coaxial Switch
> At 11:40 PM 7/23/2002 -0400, Ed Tanton wrote:
> >Get the Daiwa Graham. They have 2 and 4 position SO-239 and Type-N
> >switches that are coaxial-cavity switches, and an order of magnitude
> >better than anything else on the market-with the possible exception of
the
> >'stand-up' Alpha-Delta switch.
>> I agree. I have both the Daiwa and the Alpha Delta units (with gas
> discharge tubes) in use. Both are machined out a solid chunk of metal
with
> cavities. The Alpha Delta is my choice (with a good ground) for those
> antennas which aren't DC grounded.
>> 73, Mike
>> - - -
>> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
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