[amsat-bb] Re: Fw: ELK or ARROW

Bob K0NR (email list) list at k0nr.com
Mon Dec 29 12:41:05 PST 2008

Bob K0NR (email list) wrote:
> amsat-bb-request at amsat.org wrote:
>> It seems improving the 2.4 dB of insertion loss of the diplexer would 
>> be a
>> better strategy (although not necessarily easy in the space 
>> available) than
>> attempting to modify what is very mechanically sound antenna.
>> 73,
>> Joe kk0sd
>    I am surprised that the duplexer/diplexer (take your pick) has that
>    much loss.
>    Has anyone verified this via a direct measurement (such as via a
>    network analyzer)?
>    Bob K0NR
I don't have a network analyzer handy, so I did an A/B test driving the 
Power Meter on my HP 8920A using a handheld radio.
At 435 MHz, the measured power with just a cable connection is 2.5 W. 
With the Arrow duplexor inserted, the power is 1.8 W.
This implies a loss of 10 log (1.8 /2.5) = -1.4 dB, more than I would 
have expected.

How accurate is this measurement? I dunno, probably no worse than 0.5 
dB. This deserves further investigation.

73, Bob K0NR

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