[Icom] Coax Switches Revisited

Sun, 18 May 2003 07:11:34 -0400

Frank, I have run those test on the Diawa cavity switches in the past.  If
memory serves, they provide about 50db of isolation per port to about 300
mhz and about 40db above that.  Dave

> [Original Message]
> From: Frank A. Ellis <[email protected]>
> To: <[email protected]>
> Date: 5/18/2003 4:15:04 AM
> Subject: Re: [Icom] Coax Switches Revisited
>
> Bill,
>
> It would be interesting to connect a wattmeter and load to the "isolated" 
> ports and actually measure the amount of RF present. A port isolation
value 
> in dB could then be easily calculated.
>
> 73, thanks for the interesting info.
>
> Frank W3UHF
>
>
>
>
>
> >From: "wjdiamond" <[email protected]>
> >Reply-To: [email protected]
> >To: "Icom@Mailman. Qth. Net" <[email protected]>
> >Subject: [Icom] Coax Switches Revisited
> >Date: Sat, 17 May 2003 20:18:46 -0500
> >
> >Hi Folks,
> >
> >Well on Thursday I decided to start doing some tests on my XXX brand coax
> >switches as to the amount of isolation between the selected rig and the
> >other 5 "grounded" positions.  I do have external grounds run to the case
> >of the switches.
> >
> >I used some very small wire and a little pickup coil run to the outside
the
> >box to a small 12 volt light bulb. When running 100 watts to the dummy
> >load, the bulb would light at about 50 to 60 % of it's normal output,
> >interesting.
> >
> >Next I unhooked the other 5 rigs from the switch and hooked the bulb to
one
> >of the unused coax connectors and fired up a rig at 100 watts in RTTY to
> >the dummy. Guess what? the bulb blew.., Burned out, toast etc.
> >
> >So, I have to wonder what is this doing to the other 5 rigs hooked to the
> >switch even though the rigs were off?  I think I know now why my Icom PCR
> >1000 had the front end fried on it.
> >
> >So, major changes took place based on these tests.
> >
> >I removed the switches and went back to my old method of isolation and
rig
> >switching by using feed thru bulkhead coax connectors mounted on a panel
> >with the various rigs hooked to the back side and then the antenna
> >selection just hooks to whatever rig I wish to use at the time. Simple
but
> >I feel it is whole lot better and safer. I will update the pictures on my
> >web page later tonight.
> >
> >This was my test run under controlled conditions and your mileage may
> >differ.
> >
> >73
> >
> >         William J. Diamond (Bill)
> >         Rogers, Arkansas USA
> >         [email protected]
> >
> >         Ham Radio Operator WR�T
> >       Flying The Flag Long Before
> >             It Was Popular
> >
> >  Please Visit My Icom Radio Page At
> >
> >  http://pages.sbcglobal.net/wjdiamond/index.html
> >
> >
> >----
> >Your Moderator: Dick Flanagan W6OLD, [email protected]
> >Icom Users Net: Sundays, 1700Z, 14.315 MHz
> >Icom FAQ: http://www.qsl.net/icom/
>
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