Ham Repeater Remote Receiver

[KG4LHQ]

Hello,

As you know below in other threads of my repeater system, now I'm wanting to possibly install a couple of remote receivers.

This is something I don't know much about but sure I can learn rather quickly.

This is for a ham UHF repeater and just trying to build this to be better.

Anyone care to get started?

[Jim202]

Hello,

As you know below in other threads of my repeater system, now I'm wanting to possibly install a couple of remote receivers.

This is something I don't know much about but sure I can learn rather quickly.

This is for a ham UHF repeater and just trying to build this to be better.

Anyone care to get started?

Your biggest hurdle to overcome is linking the remote receivers back to the common point where the audio can be used in a voter system to supply the common selected audio into the repeater. Using rented phone circuits can cost in the order of $30 to $50 for each line per month. Use of a radio link would cut the monthly line charge but cause a few problems of it's own.

Need to come up with a voter before your going to even make the next step. Different voters require different audio control of each voter receiver. Then you have the issue of trying to key a link transmitter and the loss of the first word in the link.

Jim

[Bill_G]

So, you need at least two receivers, a voting system (comparator), and a way to transport the receive audio back to the voter as well as the transmit audio from the voter to the base station. The voter becomes the repeater controller.

Ideally, your receivers will all be the same model radio with line driver modules for telco lines.

Ideally, one of these receivers needs to be located at the transmitter site just in case the voter or the transport layer fails so that the repeater can fall back to in cabinet repeat (if capable). It is not unusual to put the voter in the same rack as the primary receiver and transmitter.

Ideally, the transport layer is fast (low latency), and it faithfully reproduces the audio with sufficient high freq noise content for the voter to operate correctly, and for control tones to pass correctly. It was generally done with analog leased line telco circuits, but those are expensive. It has also been done over T1 microwave, IP microwave, DSL service, and RF links. The transport layer could easily become the most expensive, and complicated part of the system.

Did you have any specific hardware in mind?

[Bill_G]

Your biggest hurdle to overcome is linking the remote receivers back to the common point where the audio can be used in a voter system to supply the common selected audio into the repeater. Using rented phone circuits can cost in the order of $30 to $50 for each line per month. Use of a radio link would cut the monthly line charge but cause a few problems of it's own.

Need to come up with a voter before your going to even make the next step. Different voters require different audio control of each voter receiver. Then you have the issue of trying to key a link transmitter and the loss of the first word in the link.

Jim

Agreed. An RF link needs to be very quiet, or the noise from the link will be factored into every receiver decision by the voter.

[N4DES]

I'm going to assume that this is amateur and if so, the link transmitters need to ID every 10 minutes when in use, just like the users and the repeater.
The trick is to send the ID without CTCSS or DPL and for it to be a polite ID that won't override the users when they are using the system.

[Will]

The trick is to send the ID without CTCSS or DPL and for it to be a polite ID that won't override the users when they are using the system.

The ID-O-Matic II board does that.

[N4DES]

Good to know...thanks!

[N7SEB]

I'll throw out a crazy option since this is for ham radio and not commercial/public safety....

Asterisk is an application for Linux that builds VoIP PBX systems - really stable platform that is super flexible. There is a plugin for Asterisk for Radio over IP and building repeater controllers via Asterisk. This is all free. The only cost is the boards/interfaces for connecting your radio via the discriminator, etc to the computer/server/Raspberry Pi, etc.

IF you have line of sight between these remote receiver locations, look at doing some 5.8Ghz wireless backhauls, place these Radio over IP boxes at each remote receiver and then at the main transmitter site and then connect to your repeater.

Here are some basic docs:
http://www.xelatec.com/xipar/simplevoter

For radios, on the inexpensive but fairly good quality I would suggest www.ubnt.com -- a NanobridgeM5-25 would fit the bill for most distances. RocketM5 and a 2' dish for bigger distances and a NanoStationM5 for shorter distances (< 3 miles)

This method saves you having to deal with ID on the RF links and "noise" for the voting controller since it is all digital/IP data.

Hope this helps or at least inspires some ideas.

[KG4LHQ]

Thanks for all thoughts, still exploring the ideas etc.

The repeater covers very well as it is just wanting to patch some receiving issues on the fringes which is very much expected.

I mean a person on a base station can talk into it from Louisville and talk to another person on the West side of Owensboro, KY. i'm really pleased with its performance.