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Old February 3rd 04, 06:15 PM
Tom Bruhns
 
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Wolfgang,

Then it's a bit of a puzzle. With two 4 cm pieces of wire connecting
a 50 ohm resistor to your meter, I wouldn't expect 2:1 SWR at 30MHz.
Maybe I can find time to try it on a good network analyzer today and
see what it looks like. As I understand your first posting, you see
the error with no balun involved, just the 50 ohms connected to the
meter through short ~4cm wires, and the error goes away when you
shorten the leads to practically nothing. Could your meter be in
error? You can check for a 2:1 SWR at 30MHz if you put 150pF in
series with 50 ohms, with very short leads right at the meter (or
through a short piece of 50 ohm line). It's always good to be able to
check your meter with some known loads--they don't have to be
precision loads for usual amateur work. For example, 50 ohms + 150pF
= 2.00:1 at 30MHz, and if you have a 5% error in the resistor and 5%
in the capacitor, you could be as low as 1.91:1 or as high as 2.11:1,
which is too small an error to worry about for any ham application I
can think of.

Cheers,
Tom


Wolfgang K. Meister wrote in message . ..
On 2 Feb 2004 10:07:11 -0800, (Tom Bruhns) wrote:

You didn't mention the specific frequency, ...


Tom - I was testing between 3 (7) and 30 Mhz

73s de Wolfgang