[Icom] Coax Switches Revisited

Sun, 18 May 2003 05:10:54 -0400

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
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