What is the true impedance of the duplexer??
Was it tuned correctly on a network analyzer, or tuned to pass and reject
specified frequencies with a signal generator and detector?
Without the correct tools, it is difficult to do the job correctly. Until I
saw a network analyzer in use, I thought that you tuned a duplexer with a
signal generator and detector. Boy was I wrong!!!
It is very hard to ensure that the duplexer impedances are correct without
the network analyzer.
You could use a Z matcher between the amplifier and the duplexer to get the
amplifier to see the load it was designed for. I suspect that if you
measure the SWR into the duplexer that you will find the SWR to be about 1.8:1.
73
Glenn
WB4UIV
At 05:12 PM 04/05/05, you wrote:
>Ok, I'm sure these duplexers are tuned correctly, but here is what is
>happening. If I inject 1.5 watts into the transmit side of this
>duplexer I get about 95% of that back, with about 1.4 watts from the
>duplexer. Then I pump 130 watts into the duplexer and only get 60
>watts back. Why such the loss with the higher power? Transmitter and
>amp are both ok on a dummy load, looks good on the spectrum analyzer,
>no problem there. The amp is rated 2 watts in for 200 watts out. I
>put in 1.5 watts, to get the 130 watts out, that is fine. Other part
>that I am confused with, the amp into a dummy load, starts out at 100
>watts and then gradually creeps upto 130 watts over about 30 seconds.
>Current draw on the power supply is 18 amps, from a 70 amp astron.
>Could it be that the power supply is slowing giving juice to the amp,
>kinda like the caps might be weak? Any thoughts?
>
>Mathew
>
>
>
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Repeater-Builder/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
