Author: Chip, WRTY997

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Repeater Upgrade

The Retevis 97S has been replaced with a Motorola GR500 running at 20 watts, and the antenna was moved to 50 feet AGL (from the front; from the back it is 30 feet AGL).

The GR500 is a 25/45-watt unit and generates 20/35 watts in low and high-power modes after the duplexer.  Testing so far reveals that there isn’t much difference distance wise between 20 watts and 35 watts, so the repeater will operation in low power mode. Operating in low power also saves the final power amplifier from burning out, as the repeater can run at 100% duty cycle at low power.

The repeater is linked into the PA GMRS Network, which has also undergone some serious changes.  Hop over there and take a look.

The Retevis 97s will be relegated to emergency and on the road use with a portable antenna system. It will be linked into the PA GMRS Network with a new node number as needed.

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Antenna change

Today I took advantage of the warmer weather and extra hands to change out the repeater antenna from a copper j-pole at the rear of the building that barely cleared the roofline to a feedline-style j-pole that is up in a tree about 50 feet from the west and 25 feet from the east. I hope that the coverage improves enough to cover a 10 mile radius without drop outs.

Previously, the repeater could hear me through those areas, but with ~10 watts of power, coverage was bleak at best. With the vertical addition and away from the structure, it should improve (fingers-crossed).

(Visitors here get put to work. You have been warned.  🙂 )

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Repeater Issue

Over the past two days, I’ve noticed that the repeater is barely putting out a signal, along with some noise issues. I moved the repeater away from the antenna and grounded it, which caused the noise to stop, but the range has not improved. I know its keying up from testing I’ve done, but I’m still not getting a good output range from it.

My next step is to change out the antenna. I was using a feedline j-pole antenna which really isn’t meant to be outside in weather unless in is encased or is waterproofed. I will probably change it out for a copper pipe j-pole on an extending pole in the next few days,

UPDATE: I changed out the antenna this morning, and tested it on the way to work this evening. Same results, except the repeater receives better now. But it still doesn’t seem to transmit more than a few hundred feet. Next step is to change the frequency to see if its interference causing a problem. If it isn’t, I suspect the final amplifier may have burned out and I certainly hope it isn’t that.

UPDATE #2 (11/18/22): Changing out the antenna only helped marginally. I checked the output of the repeater and it was right where it should be. So I checked the output frequency, and sure enough, there was all sorts of interference going on.

I changed the frequency back to 462.550, only to find that there is another repeater somewhere in York or Adams County that is not listed on any of the GMRS websites and does not have an identifier on it transmitting so strongly I could not get into my own repeater. So my choices were to move it to 462.600 again, or up to 462.675. As there seems to be a lot of interference coming from other RF devices near me, I moved it up to 462.675. Its been very quiet since then. I’ll test it so more tonight as weather permits.

I also left the copper j-pole antenna connected, but moved it to the east side of the building to get it above the roofline. I’m hoping that will help a little as well with coverage.

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Antenna Research, Part 2

I found a website where I could calculate the range of my repeater. I ran the numbers, at it came out surprisingly accurate. Most of the good coverage is along the Susquehanna River and from high elevations. I have to figure out a way to get the antenna higher without causing my landlord heartburn.

NC600 Coverage map

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Frequency Change

The repeater went through a frequency change due to possibility I was interfering with another repeater. The new frequency is 462.600 +5 PL 103.5.

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Antenna Research

In an effort to get better coverage out of my 10w Retevis 97s repeater, I have been working with different antenna systems. I’ve tried a ladderline j-pole hanging from the eves, a copper pipe j-pole on a 6 foot pole (outside the window at a 45 degree angle), and a fiberglass encased stick on a 6 foot pole (outside the window at a 45 degree angle).

So far, the best antenna has been the ladderline j-pole. It may be the angle of the antenna that is causing better coverage, as the other two were at a 45 degree angle to the ground, the ladderline j-pole is closer to a wall, lower in altitude by five feet, and partly obscured by the building.

More adventures / testing to follow.

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GMRS Repeater linking

The linking of GMRS repeaters to each other is a controversial subject at best. There are many interpretations of Part 95 as to whether it is legal or not. Your mileage and interpretations may be different from mine. This is not a debate on whether or not linking GMRS repeaters is legal.

I have been searching through the Internet to find out how the linking is done, I found several organizations have linked their repeaters through a state or regional group. Most state groups I found are west of the Mississippi, and most regional groups are east of it. There are only a few organizations that exist on a national basis, and there are not a lot of repeaters listed in any of them. Everyone seems to be using the same software, which is the AllStarLink Asterisk system designed for amateur radio.

In my state, Pennsylvania, there is no cohesive system in place. You will find a few repeaters linked through myGMRS or GMRSLive, but nothing you could call a state network. It seems to be based on the repeater owner’s choice as to what repeaters are linked. In south central Pennsylvania, there was a group that had started to link repeaters throughout the Susquehanna River valley. It was a well designed system with very little overlap in coverage areas. However, it was reported to me that the FCC visited with the repeater owners and told them that they could not link their repeaters. A month later, only two of the repeaters remain on the air and they are not linked.

To me, linking repeaters is a good idea for several reasons. A linked system can help get information to the right place during an emergency. A linked system would allow travelers to communicate with family in different areas. A linked system would allow travelers to talk about various road conditions so that drivers could avoid a major accident or weather problem.

However, there can be drawbacks. One user of the system could tie up all of the repeaters and possibly prevent emergency information and traffic from being communicated to the people who need it; the remedy for this is to drop that repeater out of the system temporarily. But the positives outweigh the negatives in my mind.