Monthly Archives: March 2014

EchoLink and IRLP Repeater Remote Access with a Raspberry Pi — Presentation

We have another interesting presentation lined up for our April 7th meeting. Don Fraser WA9WWS will show us how an inexpensive Raspberry Pi based node supporting either or both protocols, EchoLink and IRLP, can enable Hammin Sams members to remotely access the Hammin Sams net. This way, members could participate in their Hammin Sams net activities while out of town.

Greg Cook, you will remember, described Raspberry Pi configurations at our meeting last month. You can locate reference material about that presentation in the Technical Interest category on this site (see sidebar at right).

This time he focuses on a need that Hammin Sams members have expressed on net. Applicability is not limited to Hammin Sams nets, though, making this a must attend event for anyone curious about practical use of these protocols or about Raspberry Pi applications.

See you there!

Repeater Pairs


Ever find yourself confused, even momentarily, about the frequencies your radio uses to work a particular repeater? Come on now, admit it, I have on occasion. So let’s review how repeater frequency pairs are specified and correlate them to your radio. This material relies heavily on the section headed Frequencies on the Wikipedia page

Download Repeater Pairs as PDF

Let’s get a clear picture in our minds of what is happening. The basic relationship to fix in our minds with regard to repeater pairs is:

  • (+) offset means the Repeater Receives on a frequency Above the one it Transmits on, think +RRAT as a mnemonic
  • (-) offset means the repeater receives on a frequency below the one it transmits on
  • Operator’s radio displays the frequency its receiver is tuned to
  • Offset amount — disregard the negative sign if there is one. Engineers refer to this as the absolute value or magnitude of the quantity between those vertical bars. The offset amount is the separation between the RECEIVE and the TRANSMIT frequencies.
  • Offset direction accounts for the sign, positive as pictured in the diagram here, negative if reversed

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