Linking Repeaters

Linking repeaters is done all over the country. When one repeater is linked to another, whoever keys up on one, can now be heard on both. This can extend the range of a radio.

And if several, well placed repeaters are linked together, the ability to communicate over the total area of all the involved repeaters can be a valuable asset to communications (especially emergency, public service, and disaster related communications). Most of us are familiar with TARCs UHF network which serves much of Eastern Oklahoma with repeaters in:

Tulsa 443.850
Manford 442.000
Tahlequah 442.225
Cavanal Mt. 442.250
Muskogee 443.100
Stillwater 444.525
Mounds 444.600 (having some problems at this time)
Ponca City 444.700 (having some problems at this time)
Bartlesville 444.975 (having some problems at this time)
McCalister 444.975
Edmond 443.250
Fayetteville, AR 444.925
Decater, AR 442.850
Ketchum 444.875 (temporarily out of service)
Daisy 444.400

Also I just found that there seems to be a linked system that covers much of Western Oklahoma. This was pulled from the internet at: http://www.srh.noaa.gov/oun/skywarn/.

"The NWS Norman SKYWARN Radio Network should be thought of as a "liaison net" during severe weather. It is not intended to collect individual spotter reports, but rather to serve as a collection point where local spotter networks can relay information to the NWS. In other words, the individual storm spotter should use their local frequencies and procedures to report severe weather to their local organization. When the local spotter net receives a report of severe weather, a liaison from that group relays the report to the National Weather Service via the liaison net. Amateur radio operators at the NWS Office will also provide radar information and the latest warnings and statements to the liaisons, who in turn pass the information on to their local spotter network.

Spotters and anyone else interested in keeping track of severe storms are encouraged to monitor these frequencies, but traffic should be limited on the liaison net. You should attempt to report severe weather to your local spotter groups instead of on these frequencies."

Much of the following is taken from http://repeater-builder.com/rbtip/repeaterlinking.html


There are other areas around the country that have linked systems as well. For example:

Alabama - 29 repeaters

Arizona - 22 repeaters

West Texas (Davis Mountain)

Cactus Intertie - icludes parts of California, Arizona, New Mexico, Nevada, Utah, Colorado, & Texas.

Colorado - 15 repeaters

South Carolina - 4 repeaters

Illinois/Indiana

Tennessee

Target Link - Parts of Pennsylvania, Maryland, Virginia, and West Virginia.


The "Remote Base" type link system is the most common because of its simplicity and low cost. Basically a second radio (even an old hand held or mobile rig) is connected to a repeater that you want linked to another. It uses that new radio as if it was a regular "user radio" on the other system. The "link" radio need not be duplex because of the way the link and repeaters are configured. Naturally the link (remote base) radio will need to be on the same band, frequency, split, and PL as the repeater you are linking to.


ae5ft, Gene, had the following information on IRLP as a mode for linking radio systems.

http://www.irlp.net/

The aim of this project is to reliably and inexpensively link amateur radio systems without the use of RF links, leased lines, or satellites.

The IRLP uses Voice-Over-IP (VoIP) custom software and hardware. Coupled with the power of the Internet, IRLP will link your repeater site or simplex station to the world in a simple and cost effective way.

IRLP operates a worldwide network of dedicated servers and nodes offering very stable worldwide voice communications between hundreds of towns and cities. All this with unsurpassed uptimes and the full dynamic range of telephone quality audio.

kd5cub, Lee, asked if anyone had any information on the FT-2000 100 watt with pep upgrade. If anyone has information on this equipment please contact kd5cub.

wa5vxi, Manuel, asked if other repeater systems use modes other than rf to connect up between repeaters (in particular, maybe using the internet).

ke5okt, Jim, mentioned that the newly running 430 repeater in Sapulpa was recently connected to another repeater (I believe in the OKC area) via Echolink (which is via the internet) but that it is not normally linked up. It can be done (and is likely being done in other places).

kd5guu, John, said that he regularly checks into an Echolink repeater on a Railroad Net on Tuesday evenings that is run out of Wisconsin. He mentioned that is a very operational and effective system.

ae5ft, Gene, added that our (TARC's) system is rf to rf, but IRLP is a very valid and easy to operate system for internet linking. He provided the IRLP info a few paragraphs up.

ke5zcz, Mike, announced that he is a scout leader and that the scouts are selling popcorn, as a fund-raiser, and that those who may run across a popcorn-selling scout, please consider buying some to help support this very worthwhile organization.

End of Net -

Tech Net Notes July 31, 2009

Here lately the Broken Arrow Amateur Radio Club has been doing some work on their 145.450 repeater located in the Bixby/Leonard area. In addition TARCs 443.850 repeater was just repaired today after a few weeks of low audio.

Also, in the recent past, RCWA's repeater got hit by a surge or a lightning strike and was off the air completely. As an interim solution, ww5wow Larry, used a repeater set up he had that would receive your signal and then re-transmit it on the same frequency. Your transmission would be stored in memory and then re-transmitted. You would hear, along with everyone else, what you just said. And this would all occur in simplex mode. The repeater would be listening and repeating on the same frequency. It made for slower transmission rates, but it did accomplish the goal of boosting a signal beyond it's limits (in most cases).

As an extension of that repeater work going on in the Tulsa area, we will be talking about repeaters here on the Tech Net tonight.

kb5vdb, Ron, sent in this explanation of repeaters:

A ham radio repeater is basically a radio system that receives the weak signal from mobile and portable radios, and re-transmits the signal on a different frequency at a much higher power level. Repeaters are usually mounted on TV and Radio broadcast towers, tall buildings, high hills, or mountains to extend the range of the station as far as possible.

The basic components of a repeater are the receiver, the transmitter, the controller, the power supply, the feed-line, the antenna or antennas (whichever applies), possibly a power amplifier, and a duplexer (cans) if one antenna is used.

There are two ways to construct a repeater:

1. Mount a single antenna as high as possible, and use it to both transmit and receive. Feed it with a single feed-line after running the signal through the duplexer. The big problem with this design is:

a. The cans are expensive, ornery, and delicate.
b. They have to be properly tuned, which requires a lot of EXPENSIVE equipment and a very knowledgeable technician.
c. They have a tendency to drift and become un-tuned.
d. They cause a lot of signal loss. (You also have to figure in feed-line loss for long runs.)

2. Mount separate transmit, and receive antennas as high as possible, separating the antennas by at least 100 feet. The big problem is expense of two antennas, two feed-lines, and of course, having to place the antennas at different levels on the antenna support. The big plus is no cans (and subsequently no loss through the cans) and if the repeater operator can locate the repeater box as close as possible to the antennas, you get most of your signal out.

There is a little delay every time that you key up, with some delays being substantial. Always allow a second or two before you start to talk.

The controller, by the way, allows a radio to become a repeater by allowing the transmitter and receiver to both operate at the same time.

ac5jm, Jerry, checked in and mentioned that there are a lot of variations to repeater set-ups but that Ron's explanation was a good summary. The on-frequency repeater, ww5wow's, is especially good for an emergency or disaster situation. It also might have an application on 10-meters since there is only 100 khz bandwidth, but nearly impossible to do without a dual site antenna. It's a good back up to have stashed away in case you need it.

The low audio problem on the 443.850 machine was a level problem. The site owner changed the temperature in the equipment room which allowed the pots to go out of tune.

ae5ft, Gene, asked. "Regarding the cans that have to be tuned: How does that fit in with repeater operation?"

k6jxy, Paul, answered, "The cavities keep the transmitter from getting into the receiver. They operate as a set. They are usually a six-pack on a set."

ke5okt, Jim, said, "I still have a KendeComm repeater that I'd like to get running on VHF. If anyone has any information on this brand or type of repeater, please e-mail me at jim@mounds.org.

ae5mn, Hank, asked, "Is there circuitry that separates the signal by detection of signal direction?"

ac5jm, Jerry, answered, "The receive side of the duplexer filters out the transmit and vice versa. The cans are manufactured for a specific range of frequencies and have to be tuned to be resonant to the frequencies used.

ke5zcz, Mike, asked. "Which repeater is better to have, one antenna/duplexer or two antennas, for a base repeater and what is the price range?"

kb5vdb, Ron, answered, "If you have a tower tall enough to separate the antenna by about 100 ft. and can get the radio close enough, you don't have the duplexers and the problems associated with them. If you don't have a taller tower, it's best to go with a duplexer. As far as costs... in the neighborhood of $5000.

ke5vas, Tim, asked, "Are there other linked repeater systems that cover as wide of an area as this one? How is the care and maintenance of the other repeaters handled?

kb5vdb, Ron, answered, "Maintenance is taken care of by the areas clubs, volunteers, and whatever funds they can raise. There was a linked system called Buffalo. It's not around anymore.

ac5jm, Jerry, added, "There are a lot of different clubs that have joined because of the affiliation with the National Weather System. The linked system is laid out to support the NWS. Ther are a few exceptions to this: Stillwater, Edmond, and Ponca City.