The "classic" Dow Key 60 Series that has been around since 1952 is a coaxial
line section. This was the one that most hams grew up with before the advent
I still have the one I bought in 1955 to use with a Johnson Viking 1 and a
Hammarlund HQ129X. These days it is used between a Johnson Valiant and
Collins 75A4 when I get the urge to play on AM
Even by todays standards (touchy GaAs Fet preamps) the TX/RX isolation is
excellent thru 500 mHz. I use a transfer style on my 2M homebrew 3CX1000A7
amp. Another is used on my 400W 432 mHz amp.
I dont know how Dow is doing these days under the Dover Corp umbrella. I was
in R&D with a millimeter wave company that Dover bought in 99 and it was a
disaster that put them under in a few more years. I bailed out before the
axe fell for an even better job.
----- Original Message -----
From: "Jim Lux" <firstname.lastname@example.org>
To: "jeremy-ca" <email@example.com>; <firstname.lastname@example.org>
Sent: Saturday, May 19, 2007 10:17 AM
Subject: Re: [TowerTalk] What relay do Ameritron and Array Solutions
> At 08:18 PM 5/15/2007, jeremy-ca wrote:
>>>The VNA might take the guesswork out of some of the measurements, but
>>>doesn't tell you much about how to change the design to make it
>>>"better". And for using "non-RF" components in RF applications
>>>(which is what most amateur market relay boxes are.. they are NOT
>>>clever stripline designs like DowKey uses) there's an awful lot of
>>>craft and art to the design, probably moreso than straightforward RF
>>>circuit design. (Unless someone's been out building HFSS models for
>>The VNA is simply a tool. As with any tool it requires that the user have
>>understanding of its abilities as well as his own.
>>The DowKey is not a stripline design, it is a coaxial line section; big
> Not the one I have sitting on my desk. It's a SP6T and it's got six
> little striplines that are moved by solenoids. I also have a microwave
> transfer switch, and it's got 4 little striplines that move
> I suspect there's lots of different designs they use.
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