2
$\begingroup$

Just want to make sure I don't need anything else (to prevent damage to the radios)

I have an antenna on my roof. It used to be used for TV but I switched back to cable.

Can I literally just use a splitter on the end inside my house and feed signal to both my Ham radio and weather radio? Or do I need something in between to protect the devices (in case of lightning for example)

Thanks

Improve this question
$\endgroup$

1 Answer 1

Reset to default
2
$\begingroup$

Antennas are designed to work best with certain frequencies. The frequencies for over-the-air TV are not that same frequencies used with VHF or UHF Ham radio or weather radio. The characteristic impedance of a TV system including the receiver, transmission line and antenna was 75 ohms. For Ham radio it is 50 ohms. Due to the bad matching the Standing Wave Ratio, or SWR, will be high. SWR is one way to tell is the antenna is well matched to radio and band it is being used on.

A TV antenna will not work for other Ham HF frequencies or bands such as 20, 40 or 80 meters.

Having said all of that, connecting the antenna to a VHF / UHF Ham radio, 2 meter or 440 MHz, will probably allow it to receive some strong signals. Same for a weather radio.

I would be far more cautious about transmitting. The SWR will probably be high and this could cause damage to radio. You also would not want to transmit if there is another receiver connected to antenna such as weather radio.

Building antennas is not hard. There are many designs such as simple J pole antennas that are suitable for VHF / UHF and dipole or end fed half wave antenna for HF. You would be better off making an antenna or purchasing an inexpensive antenna. Many contacts have been make with a inexpensive mag mount antenna siting on metal cookie sheet siting on top of a book case.

Improve this answer
$\endgroup$
4
  • 1
    $\begingroup$ Be sure not to overlook @jim's mention about not having two radios connected to the same antenna if one of them will transmit. You would almost certainly blow out the receiving circuitry on the weather radio when you key up on the ham. :) $\endgroup$
    – David Hoelzer ♦
    Mar 10 at 15:33
  • $\begingroup$ 75ohm-to-50ohm is only a ~1.5:1 VSWR so by itself, that's not generally an issue. $\endgroup$
    – mike65535
    Mar 17 at 13:27
  • $\begingroup$ What about lightning protection?? $\endgroup$
    – Phil Freedenberg
    Mar 17 at 21:21
  • $\begingroup$ You don't say where you're located, but in the U.S., Weather radio is close enough to the VHF high TV band that (everything else not withstanding) the antenna should work ok. $\endgroup$
    – Duston
    Mar 18 at 18:36

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .