Devin Posted September 30 Report Posted September 30 I think I am having an issue with what feels like interference while receiving in my house on both the n9tax single band GMRS and a simple rubber ducky. But the odd thing is I get get crystal clear transmit and receive to a repeater 43 miles away, but I get poor reception with people in my neighborhood within 1/2 mile range. Does anyone know what could be causing this? I have tried two different radios and antennas. I am going to try shutting the main power off to the house and run some test as well. Quote
dosw Posted September 30 Report Posted September 30 Yes. The repeater has an awesome antenna at an elevation that provides near perfect line of sight to your radio's minimal-value rubber ducky antenna. Your friends within 1/2 miles are not "line of sight" to your antenna; there could be trees attenuating signal, buildings, hills, and other obstacles blocking your antennas. If you can see the other antenna, you can talk. If you cannot, all bets are off. The repeater must have a high gain antenna, may be outputting near 50w into the feed line, with high quality cable, the antenna may be on a tower, and it may be up above obstacles. Probably all of these things are happening. By way of example, a 70cm ham radio (UHF, very similar to GMRS) can transmit to the ISS (250 miles away) with a Yagi antenna pointing in the right direction, and with less than 5w output. On the other hand, two 5w handhelds may not be able to communicate with each other more than a few hundred feet away. The difference is almost always line of sight first, antenna design second, power a distant third. AdmiralCochrane, Socalgmrs, TrikeRadio and 1 other 4 Quote
Socalgmrs Posted September 30 Report Posted September 30 1 minute ago, dosw said: Yes. The repeater has an awesome antenna at an elevation that provides near perfect line of sight to your radio's minimal-value rubber ducky antenna. Your friends within 1/2 miles are not "line of sight" to your antenna; there could be trees attenuating signal, buildings, hills, and other obstacles blocking your antennas. If you can see the other antenna, you can talk. If you cannot, all bets are off. The repeater must have a high gain antenna, may be outputting near 50w into the feed line, with high quality cable, the antenna may be on a tower, and it may be up above obstacles. Probably all of these things are happening. A 70cm ham radio can transmit to the ISS (250 miles away) with a Yagi antenna pointing in the right direction, and with less than 5w output. On the other hand, two 5w handhelds may not be able to communicate with each other more than a few hundred feet away. The difference is almost always line of sight first, antenna design second, power a distant third. This. What radios are you using? What antennas are you using? What are the other guys using? Do you have line of sight? Quote
AdmiralCochrane Posted September 30 Report Posted September 30 dosw nailed it. That's how radio works. /end thread Quote
Devin Posted September 30 Author Report Posted September 30 Thanks, it probably is just a line of sight issue, and/or the radios and location transmitting to me. It’s just kind of weird because my house is two stories and my window faces the direction of the people I am trying to talk to. But the repeater is in the opposite direction and traveling through 4 walls to reach my antenna. And yet I sound great and hear great . Also when I go outside on the lower level with worse line of site I get better reception than in the house. That’s why I was think it might be rf interference. As for what I am using I have tried two radios and two antennas, tidradio h8 and radioddity gm-30 plus. And I have used both the rubber ducky and the n9tax single band centered on 464.5 my best reception is in my truck in the driveway using the UT-72g. Quote
GreggInFL Posted October 1 Report Posted October 1 2 hours ago, Devin said: Thanks, it probably is just a line of sight issue, and/or the radios and location transmitting to me. ... my best reception is in my truck in the driveway using the UT-72g. Same here with the same antenna. That mag mount on the truck helps compensate for poor LOS. Quote
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