Bill, Also check for any new, continuous carriers which might have entered the environment. If you have a ground loop in the cabling, and it happens to resonate near the frequency of a new signal in the area, that signal may have exposed a flaw in the harness which has always existed and simply wasn't "attacked" before.
If this is the case, you may actually have to detach a shield somewhere to solve the issue. This can be hard to do in ham systems which use the shield as an audio conductor in an unbalanced audio circuit. Sometimes a small transformer is the most elegant fix. 73, Paul, AE4KR ----- Original Message ----- From: [EMAIL PROTECTED] To: [email protected] Sent: Saturday, August 09, 2008 10:08 AM Subject: RE: [Repeater-Builder] Hum on MSR200 Receiver Thanks for the input(s). Here is a link to the repeater info with a photo. I think it would be a single power supply. http://www.n5ztw.com/W5MOT.htm The hum is not exclusive to the IRLP linking radio as it is present when the IRLP rig is off. The IRLP linking rig and internet connection are about a mile away. I will drive up there and look at the audio cables. I suspect a bad ground. The machine is located in a commercial repeater building with a ground strap around the base of the wall. It could be a number of things including the installation of new commercial equipment in the room. Bill N5ZTW ----- Original Message Follows ----- From: "Mike Besemer \(WM4B\)" <[EMAIL PROTECTED]> To: <[email protected]> Subject: RE: [Repeater-Builder] Hum on MSR200 Receiver Date: Sat, 9 Aug 2008 11:33:12 -0400 > Does the receiver share a power source with the rest of > the repeater, or is it separate? Our machine has several > internal sources of power. each feeding a different device > (transmitter, receiver, controller, etc.) So, it's > possible for the power supply to develop a bad filter on > the receiver side, causing a hum on repeated audio but not > on the ID's. > > > > Just a thought. > > > > 73, > > > > Mike > > WM4B > > > > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of > n9wys Sent: Saturday, August 09, 2008 11:06 AM > To: [email protected] > Subject: RE: [Repeater-Builder] Hum on MSR200 Receiver > > > > It just doesn't know the words.... ;-p > > Mark - N9WYS > > -----Original Message----- > From: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> On Behalf Of > Bill > > Howdy group. > I have a Motorola MSR2000 repeater on the ham bands that I > maintain. VHF 147.32 in Austin (Oak Hill)Texas. > It has developed a hum on the receive signal. I know it's > the receiver as there is no hum when the machine ID's > with no input from the receiver. The hum has been getting > worse and now I need to take a look. I have schematics and > instruments. I'm asking to see if anyone has seen this > kind of issue before. I run a 114.8 PL but it sounds more > like 60Hz not 114 hz I'll have to look at the audio and > measure. The machine is on IRLP if anyone wants to take a > listen the node is 3364. Any input would be helpful. Jim > K5VPW monitors the machine and runs the IRLP node so he > may be listening and is willing to assist. Bill N5ZTW > > > > > > > [Attachment: image001.jpg] > [Attachment: image002.jpg]
