[Amps] UHF connector discussion For Dummies

[David Kirkby]

On 14 November 2013 00:32, Charles Harpole <k4vud at hotmail.com> wrote:
> Summary for people like me.... IT DOESN'T MATTER.
>
> 73
> Charles Harpole k4vud at hotmail.com

Well Charles,

if something was done and it was done wrong, then it would matter, as
the results would be invalid. The effect of the SMA to BNC adapter is
not accounted for, and depending on how the VNA was calibrated, could
cause significant errors. But Larry has done some other tests (not
mentioned), that indicates his results are valid.

There's a lot of people creating web pages, claiming all sorts of
wierd and wonderful things, but are seriously in error, but seem
believable to others. Here is one example

http://www.rason.org/Projects/collant/collant.htm

but there are many other web pages like, especially on antennas, where
many hams write complete and utter rubbish, but it looks well
presented and believable.

Dave

>> Date: Thu, 14 Nov 2013 00:08:25 +0000
>> From: david.kirkby at onetel.net
>> CC: amps at contesting.com
>> Subject: Re: [Amps] All the recent UHF connector discussion
>>
>> On 13 November 2013 22:45, Larry Benko <xxw0qe at comcast.net> wrote:
>> > I had made some UHF connector measurements recently and this discussion
>> > encouraged me to publish them.
>> >
>> > If interested see
>> > http://www.w0qe.com/Technical_Topics/uhf_connector_compensation.html
>> >
>> > 73,
>> > Larry, W0QE
>>
>> Larry,
>> I'm not a fan of UHF connectors, but your article was interesting, but
>> there are a few things I don't understand.
>>
>> 1) You don't describe how you calibrated the VNA which is not so easy
>> with PL259 as I'm not aware of any cal kits!
>>
>> It looks to me like you have the open, short and load from an Agilent
>> 85033E 3.5 mm cal kit in the picture, with BNC adapters on them. But
>> if they are present when the calibration of the VNA is performed, the
>> error correction will not be correct, as the offset delays of all the
>> standards will be increased dramatically.
>>
>> From memory the offset delays of the opens and short in that kit are
>> around the 30 to 32 ps, but your adapters will probably add double
>> that, so all the error correction wil be wrong.
>>
>> 2) Assuming you got a valid calibration, again there is no mention of
>> the effect of the BNC to SMA adapters. But if the calibration is not
>> valid, it changes things a lot.
>>
>>
>> Dave
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps