Back in the days when the radio waves were not crowded, most all radios were open squelch. Nobody had even heard of tone squelch, let alone digital coded squelch. There was no need, as the two-way frequencies were like the ghost town and the broadcast and shortwave frequencies were down town.

About the time radios began to become affordable, more and more plumbers, taxi cabs, tree trimmers, bakeries and others began to find needs for radio communications. Since the two-way spectrum is limited, the channel congestion began to cause headaches. Tone squelch was tried as a way of keeping radio users in different coverage areas from interfering with one another. It wasn't long before radio repeater providers discovered that they could add more users to the same repeater in the same coverage area and that several different groups of users could share the same repeater, but not have to listen to one anothers traffic.

The time line gets more complicated from there, but this is the point where we break off from the history lesson and dive into GMRS stuff again.

GMRS repeater pairs are limited to 8 channels. Sometimes, largely populated areas have more than one repeater on the same channel pair, covering the same area. Using different PL or DPL tones keeps people and the various systems from interfering with each other. In the interest of satisfying the devil in some people, they feel the need to disrupt communications between licensed users. Since it is illegal to use the raunchiest swear words we know on the air, we simply call these Satan worshippers ‘Jammers’.

Jammers appreciate a good adrenaline rush. Repeater owners have never appreciated the creativity of Jammers, so they quickly found a way to end jamming once it starts: turn the system off. Obviously, this means that the system is no longer available to the intended users, but of course this also means none of the system users will be informed by a Jammer that their mother is also for hire.

Unfortunately, many of the Jammers caught by Northern California GMRS direction finding teams have been ham radio operators using modified ham radio equipment to perform the jamming. This creates an unusual situation in that this kind of Jammer is supposed to know better. This kind of Jammer is also likely to have nothing better to do than jam the GMRS system for more hours than the users can endure.

So, thanks to the modern miracle of the ‘Repeater Tone Panel’ (also known as a ‘Repeater Controller), we now have the ability to turn the entire system off, and we even have the ability to program certain PL or DPL tones active/inactive right over the air.

Shift gears

When the FRS band became reality, GMRS repeater owners around the country were horrified to find that FRS channels 8 through 14 were right next to, and in between their repeater input frequencies. The GMRS community has for a long time been very protective of the spectrum near repeater inputs since we all know that interference is worse when the receiver getting hit is high level (like a repeater). Of course, our FCC (Federal Cash Cow) insured us that such interference was impossible. Well, at least in Washington I guess it could be impossible, but in Reality, USA the problem is very real.

In California, the tone 67 Hz. used to be quite popular. Some systems still use 67 Hz., and it seems most FRS users when they enable their CTCSS tones seem to use 67 Hz. (tone 1 for them) as well. All over Central California, there are areas where high level repeaters can be heard unsquelching from FRS radio traffic day in and day out. Hearing off-frequency FRS ringer tones is becoming as common as hearing sirens in big cities.

Controlling the repeater station takes on a whole new meaning now that FRS is wedged in between the GMRS repeater input frequencies. Now, repeater owners are faced with the traveling FRS interference problem much more than the occasional Jammer. However, the FRS problem is such that the users do not even know they are causing the interference. The repeater owner can either turn the repeater off, or endure the horrible noise while the FRS conversation continues.

It is true that some repeater stations have very narrow receivers and are less prone to off-frequency interference than others. However, what do you do when the interference is almost right on your receiver frequency?

Some of the FRS radios submitted to the GMRS Web Magazine for review have been WAY off frequency. As a courtesy to some of the manufacturers who submit radios for review, the GMRS Web Magazine reviewer submits the completed review to them prior to publication of that review. When a radio is out to lunch, we say so in the review. This can cause a review to never be published since such a condition could be embarrassing. One radio maker sent a replacement radio for review instead.

Now the problem is compounded by FRS radios that are distributed for consumption that are way off frequency to varying degrees. I have personally taken a new FRS radio right out of the package and witnessed the frequency off by 10 Kc. This puts that certain FRS radio within the receiver bandwidth of even the most selective repeater station. Now what?

The most obvious solution to date has been to abandon CTCSS tones and use only DCS tones for repeater input. Since very few FRS radios made today have the ability to do DCS, this makes the most sense for GMRS repeater owners. Obviously, older equipment that was not designed to operate DCS is at a severe disadvantage and will likely need to be replaced with more modern equipment capable of DCS. This is a financial burden, and not something many GMRS licensees would be willing to do.

Back to the controller, next to switching over to DCS input, the next best thing to do is program your repeater to be OFF at all times until you want to use it. Pressing a DTMF sequence to enable a repeater for use, then disabling it after the conversation is over can be cumbersome. Although, for older equipment, this may be the only alternative to the dreaded call ringer day and night.

The repeater owner has just as much responsibility for their remotely located repeater stations as they do their own base or mobile radios. Having the ability to keep control of the repeater station from remote locations at any time is important and almost a necessity.

Becoming a repeater owner binds you to an even higher standard of GMRS operation. Not only do you have to worry about your own radio communications, but now you have added the anxiety of the operation of your equipment by other users as well. You can't be everywhere at once, and you can't baby sit a GMRS repeater every moment of the day. Keeping some control via remote means is the only way to go.

Gummers^(TM) is a trade mark of Paul Shinn