Mark, it mainly depends on the "between port isolation" of the switch that you are going to use and the output power. There are some minor things to pay attention too like a poor quality (= poor shielded) interconnection cable. A 10 ft coax with poor shielding can pick up enough energy (especially under high power conditions) to put your receiver/s on risk. The higher the frequency and the higher the power you are running the higher will be the picked up power with all other variables constant.
A typical laboratory grade switch will have an isolation of 100 dB or more. Thats how good the shielding of your cable has to be in order to take advantage of the switch´s isolation. A typical ham radio coax switch (DAIWA, Ameritron, MFJ, ALPHA Delta and alike) has about 60 dB at best and sometimes only 40 dB at 28 MHz. With one kilowatt on the port in use you have 100 mW (S 9+93!!) leaking thru to the unused ports. How much it is exactly depends on the length of the cable connected to the unused port and the termination (radio on or off etc.) If 2 radios to one antenna (or vice versa) is all you need then a two-way coax switch could provide some extra relief as you can terminate the unused port with 50 ohms and get another few dB of isolation. Multiport switches for 3,4,5 or more ports with isolation more than 80 dB are hard to get and EXPENSIVE! Roger/DL5RBW ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
