Re: UHF connectors [was: Array Solutions Lightning Arrestor]

Posted by alorona on Feb 11, 2018; 7:49pm
URL: http://elecraft.85.s1.nabble.com/Re-UHF-connectors-was-Array-Solutions-Lightning-Arrestor-tp7638106.html

Excellent. Thank you, Alan. Data for this particular measurement are very difficult to find on the web -- of course it took an ex-HP guy to do it!

Times Microwave (a manufacturer of coaxial cable) says 0.01 dB per UHF connector pair (PL-259-to-SO-239) at HF; I have seen other private measurements that estimate 0.02 dB; and now this data from N1AL. I usually take the greater of these, 0.02 dB, as a worst-case number. But Alan's measurements pretty much show that the loss at HF is almost too small to measure-- even if he had performed a full two-port cal.

Even so, you might be surprised to see how quickly it can add up. Beginning at the transmitter output (or receiver input) it is not uncommon to find 20 or more UHF connections in the path to the antenna. Using the 0.02 dB worst-case figure, that's at least 0.4 dB, or 9% of your power. I wouldn't worry about that but I know there are folks on here that would be bothered by that.

This, of course, is not counting loss in cables, filters, lightning arrestors, power meters, bulkheads, switches, antenna tuners, baluns, amplifier through-paths, transmission lines, etc. These can add another dB or more to the total and far outweigh any loss in UHF connectors. If you want to minimize losses, UHF connectors are the last thing you should worry about.

I encourage you to do an analysis to determine your system efficiency. I recently did so and discovered that I have a worst-case loss (to the feedpoint up at the antenna) of 1 dB, which is 21% of my power. Gone. Forever. Whoosh!


Al  W6LX





_______________________________________________________

             --------- Type N --------   ---------- UHF ----------

FREQ (MHz)  TOTAL  LOSS PER CONNECTOR   TOTAL  LOSS PER CONNECTOR

1.8         0 dB   0 dB                 0 dB   0 dB

30          0      0                    0      0
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