FM_repeater_map

Hunting for FM repeater frequency?

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Ways to easily find FM repeater frequencies

Version 1 – The USA is not that far away

The lowest FM repeater band for ham radio can be found in HF between 29.6 and 29.7 MHz with channels 10 kHz apart and with a frequency shift of 100 kHz.
The advantage of this exciting HF band is it’s long distance communication capability when propagation conditions are at least fair, i.e. Solar Flux Index (SFI) is high enough, and the geomagnetic Kp index converges to zero – or at least not greater than two.
HF frequency propagation is tricky, and solar flares may produce X-rays as well, but the ten meter band is not so vulnerable, which is why it was chosen for repeaters.
In practice I have often heard 29 MHz repeaters from the USA.

Version 2 – World wide waves

Another widely used band is allocated around 145 MHz with 12.5 kHz channel spacing and a 600 kHz frequency shift. There are a great number of FM repeaters all over the world employing it.

A detailed list can be found here:
http://ac6v.com/repeaters.htm

Somewhere on the high mountains

Some popular repeaters are sited on high mountains, and can cover a rather large geographical area. An example is the Királyhegy (Králova Hola) repeater near Poprad, Slovakia transmitting (downlink) on 145750 kHz. It’s a bit old styled, because one must use a short 1750 Hz tone burst to start communication. Beside this, you can use it without CTCSS code. A transmission from this repeater can be seen on the waterfall display of the SRM-3000 software receiver running on the Quadrus SDR platform in direct digital VHF mode.

Screen Shot 01-02-15 at 08.09 PM

According to a recent International Amateur Radio Union (IARU) recommendation, 145 and 432 MHz FM repeaters are mostly equipped with CTCSS encoding. Without that code one can not communicate through these repeaters.

Learn more about CTCSS encoding.

One can see the locations and callsigns of repeaters in Google Earth using the file waypoints.kmz.

This is an example from the Carpathian Basin:

FM_repeater_map

Callsign dictionary

Those callsigns with a letter V in the suffix are 145 MHz FM repeaters, and those with letter U in them are UHF repeaters. UHF repeaters have been more popular recently, which is partly due to the small sized antennas used mainly with hand held radio sets. Channel spacing is usually 25 kHz, and the frequency shift is 7.6 MHz in the 435 MHz FM repeater band.
CTCSS codes are generally used on almost all 70 cm repeaters.
The perhaps best Hungarian UHF FM repeater, HG7RUE, is sited on Szechenyi Hill in Budapest in the old building of the first TV broadcast transmitter. Its downlink frequency is 438775 kHz and the CTCSS code is 114.8 Hz. As the DRU-244A SDR digitizer hardware in the Quadrus SDR platform has no input frequency limitation, one can use the receiver in direct digital mode even up to the 70cm HAM radio band.

An interesting link of the Hungarian repeater map:
http://ha2to.orbel.hu/content/repeaters/en/ctcssplan.html

Special thanks for the info and content to HA6NN, Bandi.

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  1. Pingback: How to receive NOAA satellite signals | QUADRUS SDR

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