One thing to keep in mind, a pair of $30 radios will never come close to being a dependable repeater. It will work for short term, short range repeating. A pair of $30 radios will not become a long term, long range, heavy use repeater system. Just throwing that out there since it sounds like your expectation is that this will give you a long range repeater system.
That being said, as for the hum a few things to check:
1) Do you have enough voltage or amperage from the power supply? Not enough volts or amps could cause some hum.
2) How far apart are the radios? If they are too close to each other, one could be desensing the other and causing a hum and/or intermittent TX. This is why actual repeaters have can duplexers to isolate the receiver from the transmitter.
3) How far apart are the receiving and transmitting antennas? Same reason as #2 above.
Maybe that will get you in the right direction of troubleshooting. Good luck, sounds like a fun project.
Thanks for the reply. I understand the rule of line of sight and cheap equipment. I plan on using this to extend the range of GMRS equipment at some areas I have had trouble with. On a temporary basis. Like, the camping trip I take to Yuma every year where the terrain is a little hilly when we go jeeping... but... there is a hill we always hike up every year that overlooks the whole area. Big time. Several hundred feet above the rest of the terrain. Figure I'll drive the Rhino up it with my 'Vault' and 'Tower' and leave it up there for the weekend. Go up and switch out the batteries once a day, or whenever. And have a fun 'toy' to brag with my dorky once a year camp guys. The rest of the year... well, my kid will have the coolest radios in the neighborhood. MS350R's for the boys, My setup on the roof gives me about a two mile radius of indoor penetration. That's with the hum...
...so I got thinking: Perhaps it was the gold connector. So I removed it, used a scanner as my RX radio (since it has a 3.5mm out) and voila, no hum. No intermittent transmit. No explanation, other than its cheap stuff and maybe it doesn't like gold? Either way, all is working fine now, and other than it not being a "perfect" repeater, it works pretty good.
The radios sit in an 'Ammo' can, with a hole drilled in the side, antenna cable feeds out separate holes. They are in the same can for now, mere inches apart, and seem to do the trick. I wonder how this will be over the long term... but hey, they were 35 each, right? I pondered giving each its own ammo can, and separate them by about 20 feet, since I have a good ten feet of extra coax leading to the 'Tower'.... I guess I could do that. Think that will improve it? My 'Tower' (again, a temp unit for camping etc.) is a five gallon bucket, filled 1/3 of the way with concrete. I put an eye bolt in there in case I want to use a cable lock at some point. A five foot mast rises from the rock, and then 'T's off with a Motorola UHF 4" mobile antenna at each end. They are separated by about 4 feet. I know this to not be ideal, but it is functioning. I don't anticipate being able to get them further apart at any time soon. I feel that the placement of the units, and the reality of it being 4 watts, will dictate its efficiency. The hill I am planning on using the spring should do the trick just fine, if not, I'm in for about 100.00 and tinkering time. I kind of consider it my 35th grade Science project.
I kind of took the idea from the video and ran with it, I guess =)
For the guy who wanted the link:
Set up a Baofeng UV-5R Repeater System - YouTube
...any help or critiques of the setup (other than the obvious, its a 35 dollar radio) would be appreciated.... hell, we can rag on the radios too, they are **it, but functioning quite well right now... always like to tweak it though.
Thanks in advance!
