Well, I'm no Smith chart expert, and I graduated from MIT but it didn't
take. :)
Anyway, if you look at a connector and assume it's close to correct
impedance (this is the only part I'd like someone else to look up), at
10M, an inch of connector is only about 3cm or 1/333 of a wavelength. Say
the velocity factor is BAD and double that. You still only have about 2
degrees on the Smith chart. See what the impedance ratios are, and go to
town.
Now I never used the reflection loss scale on the bottom, but a friend of
mine did some fancy protractoring and told me you get about .01 dB
reflection loss for a 200 ohm connector.
At 300 MHz, you get more like 20 degrees, which could be bad.
Basically, like Tom said (I think it was Tom, anyway) if it's not heating
up, don't worry about it. The power has to go somewhere.
On Thu, 30 May 2002, RCARIELLO wrote:
> As a side subject to the topic: "Really dumb question on coax"
> and then a second subject topic of: "There are no dumb questions on Tower
> Talk, only dumb answers!"
>
> I will submit the third subject as a topic.
> Dose anyone know what the loss introduced into the circuit is from the use
> of these connectors?
>
> My interest is in the RF range from 1.8 to 30 MHz.
> The connectors all nickel plated.
> I would like to information about a:
> PL-259
> PL-258
> SO-239
> 85-877
> PL-259 90 degree (Can't find the stock number)
> PL-259 Tee (Can't find the stock number)
>
> As a side note I called Amphenol for this information. The person I spoke to
> was very friendly but unable to provide me with any information. The comment
> from someone he spoke to was that the loss was insignificant within the
> frequency range up to 300 MHz. The connectors were tested many years ago but
> the results are not available.
>
> If it hasn't already been done this might be a good project you someone
> going to MIT.
>
> Rich AA2MF
>
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>
--
Hisashi T Fujinaka - htodd@twofifty.com
BSEE (6/86) + BSChem (3/95) + BAEnglish (8/95) + $2.50 = mocha latte
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