Re: Shootout of Substitute SG504 heads = a better head.


 

Hi Craig,
I don't expect to be able to measure such a small difference. I expect to
learn more about HOW to measure such small differences. I see it more as an
opportunity to sharpen my measurement skills and make them more accurate.
David and Ancel have the RF Measurement equipment and the RF experience
necessary to make these kinds of measurements. What I have is older Tek
equipment that can be used, with some cleverness on my part, that I hope
will approach their accuracy and precision and fill in the gaps between the
frequency test points they used.

When I get Ancel's head I will have all three heads to compare. I also have
a different measurement methodology than David and Ancel which you can read
about (with pictures) in the archives. You can get it at
https://groups.yahoo.com/neo/groups/TekScopes/files/015-0282-00/
Its title is 015-0282-00 Head Comparison.pdf.

So my ultimate hope is to make a small contribution to the results and learn
more about how to make RF measurements in the process.

Dennis Tillman W7PF

-----Original Message-----
Sent: Sunday, March 20, 2016 11:54 PM
Subject: RE: [TekScopes] Shootout of Substitute SG504 heads = a better head.

Some might wonder why it would be worth concerning ourselves with
differences that are less than 0.1dB. The answer is simple - because we
can.
Dennis Tillman W7PF
I agree with the sentiment Dennis - I'm just as anal about measurement
accuracy as most of us. But in practical terms, 0.1dB (even as a delta) is
(a) very hard to measure (b) you can easily see differences of this order,
and larger, by wobbling a BNC connection or inaccurately torqueing an SMA,
(c) is right on the hairy limit of insertion loss and VSWR for top flight
SMA's http://www.amphenolrf.com/connectors/sma.html and certainly on the
hairy edge for BNC's http://www.amphenolrf.com/connectors/bnc.html and (d)
is less than 0.1 division on an 8 division screen.

Craig
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Posted by: "Craig Sawyers" <c.sawyers@...>
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