Coax jumpers

John Tyson — Thu, 03 Sep 2009 18:52:25 GMT

Is there really specific lengths for 52 OHM coax used as jumpers between;

radio and amp,amp and SWR/wattmeter,etc.Thanks for an answer

RE: Coax jumpers

tre1129 — Sat, 05 Sep 2009 17:39:59 GMT

Hi John. I'm not really sure. Have you tried asking someone in the business?

RE: Coax jumpers

Donald — Sat, 05 Sep 2009 23:08:40 GMT

So long as the source resistance and the destination resistance is the same, the length of connecting coax doesn't matter. Coax length matters if the two resistances or impedances are not the same. The coax then becomes a matching transmitter. In this case the length does matter and can be used to match dissimilar impedances.

RE: Coax jumpers

Sparky — Tue, 08 Sep 2009 21:49:23 GMT

Knowing what frequency this transmitter is operating on would be helpful. This length issue would only be relavent for a fixed frequency.

RE: Coax jumpers

John Jewkes -W6HNC — Tue, 08 Sep 2009 23:29:43 GMT

Several depends-on things come into play. Usually, the length will not matter, so long as the coaxes are the same impedance, have proper connectors on them, and are not so long that they get looped up. (The looping can act as an inductance coil under the right circumstances adding 'loading' to the circuit. Also, when used for a specific frequency, such as a repeater, or as a digipeater on HF, length can affect, and of course the fact of whether it is fully shielded, or like radio-shack coaxes only partly shuielded. Velocity plays as big a part in detuning an antenna circuit, as it can create heat/resistance and therefore SWR increasing. Also, there is a loss per foot that will limit how long things can be in setting them apart. Different 52 ohm coaxes will have different loss per foot ratios as well as being more suited to one frequency range (Band) or another. Good Luck, es 73 de John Jewkes, W6HNC