>>The general rule is a one degree long impedance bump can be tolerated
>>with no ill effect on impedance measurements. That's over one foot
>>on 160 meters, and 1/4 inch on two meters. It's pretty darned easy to
>>use BNC's and homemade fixtures to get into the 500 MHz range with
>>excellent accuracy. On 160 meters you could use a Radio Shack clip
>>lead!
>Now I understand! On my planet that rule is not currently enforced. I bet
>that the Radio Shack franchise on your planet also stocks APC-7 to UHF
>adapters.
Larry,
While I don't agree with Tom on a lot, I do agree with him here.
Clip leads COULD very easily be used on 160 meters. Certainly not at VHF
though. Tom is not saying that.
The size of the connector relative to wavelength at 160 is so small that
it really doesn't matter. And BNC connectors are spec'd WELL up into the
GHz range.
I've also never seen an APC-7 connector at Radio Shack!
I've done plenty of quick and dirty measurements on amps even at 800 MHz
and get good results doing it the quick and dirty way. IMHO, you only
really need to worry about reference planes and so forth when the
connector begins to be a significant size relative to the wavelenght (ie.
GHz ranges).
Is using high quality connectors going to give better results? SURE.
But how much accuracy do you really need at HF or even just to prove a
point for that matter? So your phase angle of S21 is off by a couple
degrees. And you magnitude of S21 is off by .2 dB. Big wup! Unless you
are trying to get that accurate, don't worry about it.
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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