You want to get rid of any 9913 or LMR foil/shield cable in the system Can be a huge duplex noise generator.
Chuck WB2EDV ----- Original Message ----- From: "kc0mlt" <[email protected]> To: <[email protected]> Sent: Monday, May 03, 2010 10:15 AM Subject: [Repeater-Builder] Re: AC buzz on VHF > Ok a little update on the AC buzz. After some preliminary investigation we > located two very noisy transformers on poles with in 1 1/2 miles of the > site. The site was disconnected and a clamp on one of the wire was > replaced and the wire attachments on our road side supply pole were check > and ok'ed by the power company. We will be doing a little more searching > with the HT in a tube method to hopefully get this taken care of. One > interesting note, with an HT on an Air band frequency when held near the > ground / power pole guy wires there is one heck of a buzz there! Even on > some of the tower guy wires we get the harsh buzz, but not all...? > > In the mean time, is there any way we can eliminate / filter out the buzz? > My thought was maybe coiling up the antenna to Hardline jumper out at the > antenna end. Our jumper is will be made out of 9913 for now. Any other > suggestions as to a filter? > > Thanks for all the input so far! > > Wade > KC0MLT > --- In [email protected], Joe <k1ike_m...@...> wrote: >> >> I had a similar problem at my house and it was tearing up my packet >> digipeater. It turned out to be microspark interference. See this >> message: >> >> http://www.mail-archive.com/[email protected]/msg50828.html >> >> It turned out to be a tie-wire that is used to hold the wire into the >> insulator on the high voltage line in front of my house. The tie wire >> was just long enough to resonate in the 2 meter VHF band, but very >> little noise was being created on the AM broadcast band. Do the test >> that I described in the above message and see if it is AC power line >> interference. If it is, you should ride around the general area of the >> tower and listen on your car AM radio. When you get very close to it, >> you should hear the interference on both the VHF and Am radio. If you >> have a handheld scanner that receives AM it will be easier to find the >> interference. >> >> 73, Joe, K1ike >> >> >> >> On 4/26/2010 10:23 AM, kc0mlt wrote: >> > Hello all, >> > >> > I am in the process of putting up a 2M repeater on what I would >> > consider a pretty vacant site. There is only one other machine (70cm >> > Repeater) currently out there. My concern is with an AC (60Hz) buzz >> > that comes across on the VHF band. It doesn't have a signal to it that >> > will key uip a radio, but when you receive an actuall signal you can >> > here it. We have heard this on both handhelds and mobiles. This site is >> > unique as it is a duel tower with old (unused)Microwave panels and >> > drums on the bridge at the top of the two towers. The microwave >> > equipment is no longer hooked up. We have had the power company totally >> > unhook the power to the site and the buzz was still present. The >> > nearest high voltage lines are about 1.5 to 2 miles away. You can not >> > hear the buzz on any AM reciever. Does anybody have a clue as to what >> > this could be and what we could to do prevent it? We have some thoughts >> > on the grounding of the guy wire being a cause but we are unsure of >> > that. Any ideas would be greatly appreciated! >> > >> > Thanks >> > Wade >> > KC0MLT >> > >> > >> > >> > ------------------------------------ >> > >> > >> > >> > Yahoo! Groups Links >> > >> > >> > >> > >> > >> > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.814 / Virus Database: 271.1.1/2851 - Release Date: 05/03/10 02:27:00
