Batboard

I have a simple set up, it’s very budget restricted. Trying to get a little more out of it with the limited budget. GR300 repeater.

Can an amplifier be added to a GR300 repeater. I would like to get more range and power out of the repeater?

The portable radios are not reaching the repeater quite like I would like. The repeater has been put in the best location possible and cannot be moved. Its nothing more than a GR300 on a shelf with a regular fiber glass antenna mounted on top of a very tall building. Our main area of operation is approximately 5 miles from the repeater site, I didn’t think that was that far but I guess it is for a 4 watt portable radio??

The portables are hitting the repeater 90% of the time but weak, there seems to be a lot of dead spots. My question is what can I do to extend range of the portables? I’m not familiar with microwave links or dual repeaters.

Would really appreciate the input on the questions above.

Thanks

Your situation seems to be more on the line of a receiver problem than a transmit problem. Have you tested the system for desense on the receiver? Unfortunately with repeaters there are a lot of variables involved.

I agree - it's a repeater receive problem. I go along with the overall concept of putting the repeater a few miles to side of the intended coverage area so that it lands in the main lobes of the repeater antenna. Putting it on the tallest thing you can find is also great since it increases your line of sight.

Where this is probably falling down is the GR receiver and duplexer. A receiver has to do two things - receive the freq of interest, and reject all others. It's the reject all others part that mobile receivers tend to do poorly. They become easily overloaded by strong signals, even out of band, reducing their sensitivity to the freq of interest (if you are lucky) by a little, to (if you are unlucky) OMG. The solution is to use external cavities and filters to improve the rejection figure. However, the standard duplexer sold with these are reject only, and do little to nothing to filter other signals.

Your receiver is essentially buck naked to the world with a giant kick me sign. And now we put it on top of a tall building with a reasonable antenna so it can be clobbered by everything for miles around.

It's time to bring in the technicians and test equipment, quantify the problem, and proceed from there. It could be a super quiet site, and it's the duplexer tuned wrong causing the problem. Or the antenna has gone bad hashing up the receiver when the transmitter is keyed. It could be a number of things including local interference by simple devices like an LCD display on an HVAC control panel, or the wifi node mounted on the same pole as the antenna. Or, since it is the tallest thing around, it is a busy site with lots of energy across the spectrum. Somebody has to go look at it plain and simple, and then make recommendations on corrective measures.

How long is the feedline from antenna to repeater and what type of line?