Building a Repeater


10 posts
by W5PKY » Wed Jan 02, 2013 10:58 pm
Well I'm working on using a RPi as a repeater controller. Currently, attempt 1 is using freeSWITCH. What I'm trying to accomplish is building a portable repeater very similar to a WiFi repeater except using two-way radios that can run of batteries and everything fit in a surplus ammo can or other waterproof container. Fiddling has of course brought up several questions. The primary question has to do with freeSWITCH and perl.

Here is what I'm using as a reference:http://wiki.freeswitch.org/wiki/Fs_rpt.pl

Now there is reference made to the Fs_rpt.pl script which has to be modified to my understanding. (Please understand I'm trying to give myself a crash course in perl as I go because that is how I learn best). However, I'm assuming that the there was an active link to the script at one point in time and it is no longer there. Is there enough info there to rebuild the scrip file without having too much knowledge of perl?

The reason I went with freeSWITCH was that it seemed to have what I needed (announcement broadcast for call sign, and the ability to link controllers over a network, DTMF decoder, roger beep) but if anyone has any other program suggestions that may or may not be easier to setup, I'm open to suggestions.

My other questions belong in more technical specific parts of the forum so they will be asked where needed (mainly GPIO ttyAMA0 connections and 2 way radio comms). Thanks in advance for any help or suggestions.
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by jamiesk » Thu Jan 03, 2013 7:03 am
I was nearly into HAM many years ago. When the Atari ST was new on the block!! :D

Basically to have a repeater you will need to alter the perl to record when a transmission is sensed. When its stopped, then re-transmit the recorded message. To achieve this you will need to
1) wire up the speaker and mike to the Pi
2) wire up the PTT to a GPIO, via a relay (and transistor to bump up the current and isolate the Pi) ?
3) the main one - how to detect there is a "message" being transmitted. Now you could "record" all the time, but how about when to stop and start the message. I'm stuck on this point.

Good luck.
Pi1 (Nov 2012 loft)= 1KW immersion controller for Solar panel
Pi2 (Jan 2013 living room)=Play thing
Pi3 (Feb 2013 mobile)= Play thing with Tandy Ladder board,breakout board,Nokia display
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=26&t=28193
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by W5PKY » Thu Jan 03, 2013 8:15 am
I was looking at going with the UV-5R radio from Baofeng which I believe takes a 3.3V signal for PTT. Planning on going with a duplex setup (so two HT's).
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by jamiesk » Thu Jan 03, 2013 8:27 am
W5PKY wrote:I was looking at going with the UV-5R radio from Baofeng which I believe takes a 3.3V signal for PTT. Planning on going with a duplex setup (so two HT's).


I hope they will be on different channels ! Have you heard of feedback and bleed ? :o
Pi1 (Nov 2012 loft)= 1KW immersion controller for Solar panel
Pi2 (Jan 2013 living room)=Play thing
Pi3 (Feb 2013 mobile)= Play thing with Tandy Ladder board,breakout board,Nokia display
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=26&t=28193
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Location: Ipswich, Suffolk, England, UK.
by W5PKY » Fri Jan 04, 2013 1:44 am
jamiesk wrote:
W5PKY wrote:I was looking at going with the UV-5R radio from Baofeng which I believe takes a 3.3V signal for PTT. Planning on going with a duplex setup (so two HT's).


I hope they will be on different channels ! Have you heard of feedback and bleed ? :o


A repeater's input is always a different frequency than the output depends on the band though. For example, If a repeater broadcasts on 147.020MHz, it receives on 147.620MHz. The radios using it transmit on 147.620MHz and receive on 147.020MHz. On the 2m band in the US, the standard offset is 600kHz above the repeater's transmit frequency (or your receiving frequency) for frequencies above 147.000MHz, -600kHz for frequencies below 147.000MHz. Of course, most radios do these offsets automatically now so the operator never really has to think about it...it just works. Of course if it were a simplex repeater, then it would listen, record, transmit recorded info.
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by w1ve » Mon Oct 28, 2013 3:22 pm
I am trying to find the source to http://wiki.freeswitch.org/wiki/Fs_rpt.pl

FreeSwitch is no longer using SVN. Do you have it?

73,

Gerry W1VE
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by Zachster1996 » Tue Jul 15, 2014 3:26 am
The Baofeng UV-5R has a feature called VOX, which is voice activated transmit. So if you could get an audio line into the Baofeng, you could make it transmit w/out worrying about wiring. The number for the VOX setting is the sensitivity. I think 10 is most sensitive but I'm not 100% sure.

73,

KM4BLG
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by W5PKY » Tue Jul 15, 2014 3:35 am
A 4W baofeng won't handle the duty cycle though. A Baofeng also runs off of 3.3V signals (you could pull PTT off the GPIO). Still need a good way to interface the input of the repeater. Big question, why not use commercial radios for you transmitter and receiver? Better receivers, tighter squelch circuits, higher transmit powers and they can generally be picked up for free if you know where to look for wideband only surplus.
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by DoninIA » Sat Jul 19, 2014 3:37 pm
I would get a couple of Motorola Maxtracs or GM300s with a 16 pin accessory connector.
All the signals you need are on the rear 16 pin connector. COR, PL Detect, PTT, TX Audio and RX Audio.
You could build an interface out of some NPN transistors and a 4049 CMOS chip.
This will buffer the inside world from the outside world.
Get the UHF versions. 5 mhz split is easier to work with than 600 khz.
Plus, UHF duplexers are cheaper than the VHF version.
Also, I would lower the power to around 5 watts.
A repeaters performance is not judged by how far it can transmit, but rather by how well it can receive while full duplexing.

I built a similar project using a parallax basic stamp.
I added a DVR, DTMF decoder and also interfaced a 2x16 display.
Had a lot of fun getting the code right.
This project is what motivated me to go to the RPi.

So far I've put together a NAS file server and APRS IGate.
A repeater controller is on my bucket list.
This will be an excellent opportunity to learn Python skills.

Good Luck,
Don J...KI0EO...
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by W5PKY » Mon Jul 21, 2014 5:50 am
DoninIA wrote:I would get a couple of Motorola Maxtracs or GM300s with a 16 pin accessory connector.
All the signals you need are on the rear 16 pin connector. COR, PL Detect, PTT, TX Audio and RX Audio.
You could build an interface out of some NPN transistors and a 4049 CMOS chip.
This will buffer the inside world from the outside world.
Get the UHF versions. 5 mhz split is easier to work with than 600 khz.
Plus, UHF duplexers are cheaper than the VHF version.
Also, I would lower the power to around 5 watts.
A repeaters performance is not judged by how far it can transmit, but rather by how well it can receive while full duplexing.

I built a similar project using a parallax basic stamp.
I added a DVR, DTMF decoder and also interfaced a 2x16 display.
Had a lot of fun getting the code right.
This project is what motivated me to go to the RPi.

So far I've put together a NAS file server and APRS IGate.
A repeater controller is on my bucket list.
This will be an excellent opportunity to learn Python skills.

Good Luck,
Don J...KI0EO...


Unless I had a Radius with a 10W PA, I'd never turn the power down that low. Especially since nearly all of my GR300's and GR500's have 40W PA's in them (I run them around 35-25W).

I don't mess with VHF…just isn't practical where I live.
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