Mathew,
I think you will find that the RF at high power is probable correct. The
difference you see between low power and high is about 17dB. Unless you are
measuring the low power down to 0.01 watts it will be difficult to find the
real loss. Provided all is working correctly the RF power levels you list is
about right. I would think a little minor tuning could get a little more
out, but not much.
The 2.2dB insertion loss is only one calculation. You have the connectors,
coax, loops (very little here) and some going through to the other side
(again, very little) has to be calculated.
Taking this into account you probable have close to 2.5dB loss through the
whole thing. If this is correct then 200 in and 137 out is about right.
Just my thoughts.
Charles Miller
----- Original Message -----
From: "n9lv" <[EMAIL PROTECTED]>
To: <Repeater-Builder@yahoogroups.com>
Sent: Wednesday, November 30, 2005 8:29 PM
Subject: [Repeater-Builder] Duplexer loss different with more power, Why?
> Ok, running the TX-RX duplexer, with a 2.2 dB insertion loss, I tuned
> the duplexers on the monitor. All three of them looked identical,
> with rejection on the rx side of -80 dBm on each single cavity. Once
> I tied them all together, the rx rejection was better then -10 dBm,
> all went well there. I input 4 watts into them all tied together,
> connected to a dummy load, and got three watts out. Then I tied the
> duplexers back into the repeater, with 200 watts input, I am getting
> 100 watts output, into the same dummy load. Refelcted power was less
> than 1/10 of a watt. What am I missing here. If I am thinking right,
> I should be getting about 137 watts back out of the duplexer, or close
> to there. Any ideas? Could there be a mismatch bewteen the duplexers
> and the amp? Cables are all ingood shape.
>
> Mathew
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> Yahoo! Groups Links
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