The inadvertent diode story has been around for a long time. I think it was much more of a problem when you had two broadcasters at a site where the difference between their frequencies was on a 2 way FM repeater input frequency. Every active electronic device on the whole site could do the same thing. Remember how everyone used to obsess about intermod products at tower sites. Doesn’t seem to be much of a problem any more. Or perhaps it is but we are all on cell phones now.
From: Bill Prince Sent: Monday, February 23, 2015 5:14 PM To: [email protected] Subject: Re: [AFMUG] 711Mhz carrier? Oh I know. Our tower manager at Black Mt. goes semi-ballistic when he sees anything on the tower that is not HDG or stainless or silicon-bronze. Then tells the story of rusting bolts/nuts/washers turning into diodes in the presence of higher-power RF. I don't know how high the power needs to get, but we have seen some interesting side-effects on unshielded cable and other unshielded components. bp <part15sbs{at}gmail{dot}com> On 2/23/2015 4:04 PM, Jaime Solorza wrote: Noise can come from most unexpected places. CQ rag had a story on spark plug caused noise on motorcycle knocking out a satellite system on bank building. Chucks advise is good And that would be my first step Jaime Solorza On Feb 23, 2015 3:08 PM, "Peter Kranz" <[email protected]> wrote: Had an AT&T contractor show up at one of our datacenter sites today and claim that one of our radio systems was emitting a carrier at 711Mhz and he pointed at where we have a Dragonwave Compact 18Ghz system and Redline AN-80i 5Ghz system mounted on the building. 711Mhz doesn’t sound like an IF of either of these systems to me, but I’ve got tickets in with the equipment manuf. It looks like they are some 3rd party AT&T has sweeping buildings downtown. Anyone dealt with these guys before? He told me he measured a -87 with his directional antenna 10 feet away from the equipment and acted like that was a really big deal, sounds like a pretty low level to me honestly. Anyone know what the legal limits for spurious emissions are in the 700-800Mhz band? Peter Kranz Founder/CEO - Unwired Ltd www.UnwiredLtd.com Desk: 510-868-1614 x100 Mobile: 510-207-0000 [email protected]
