Wierd noises on Mil/air channels

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hawkeye32

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Not sure as to what could be causing this but when i scanning and lands on any channels from 285.00-390.00 I get a noise/sound that sounds like a a warning siren going off in a jet before it goes down??? I thought perhaps it may be a training exercise, but its almost on all these channels listed in this zone.. Hard to listen to whats going on cause the sound overrides the talk, any idea of what this could be???
 

hawkeye32

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Also as far as i know i am not close to any towers the land is pretty much flat not sure if that helps
 

ka3jjz

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Hearing it on multiple frequencies is a sure bet you are getting overloaded by something - perhaps a pager, or multiple pagers. You can buy filters that will knock this down and out from places like PAR electronics. Somewhat expensive, but excellent performers and support. You can search out the comments about them in various places, including here on RR.

73 Mike
 

hawkeye32

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ok thanks you know any palces that sell these, i am used to radio shack back home but here in canada i guess they don't have them anymore
 

nycrich

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Sounds like you are picking up oscillator interference . These oscillators are a several Mhzs in bandwidth, why it expains you are not getting it throughout your radio. The local oscillator in a television, sat receiver,including anything that transmit ( wireless home phones, modems, computers) have caused this problem before for me. You could be picking it up if your radio is in the same room, or from your antenna that is picking it it from a strong source nearby/outside. Start with your room by turning off one device at a time while you are on the affected freq.
I found my sat receiver was causing my problem across from my radio in the same room.
 

ka3jjz

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That could very well be - I'd take a handheld or cheap radio and start sniffing. Save yourself a couple of bucks....73 Mike
 

hawkeye32

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ok well looked around only thing that is in the same room is a cogeco digital box, comp has no wireless (desktop), no routers,modems , only thing wireless is cell phone, but soon enough here in a couple days i just purchased a scantenna plus it is going to be mounted to a 40 foot mast ,i'll see if i get the same sounds then,i'll post back, if it does if my antenna is outside can this still happen??
 

ka3jjz

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That digital box - is that for cable or something? I'm not familiar with the brand - is a prime suspect. Cheap boxes can be horrific RF radiators.

Getting an antenna outside, away from the potential source, and fed with good quality coax is going to be a big help. You may find other sources of RF junk, but if that digital box is the culprit, it should knock it down quite a bit. nycrich has the right idea - if you can turn it off and unplug it, see if the interference is gone. If it is, you know you've located the offender.

73 Mike
 

hawkeye32

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ok cool thanks,it only appears to happen on the Mil/air freq, any of the others it operates fine,and yes it is a digital cable box,i'll post back once i get the antenna up, as for the coax i believe it is a RG8U i know this is lower grade...Any idea of where i can get 9913 cable of about 60-70 feet...I am in canada just recently move here from the US so back home i would just go to radio shack,but here in canada their are no radio shacks...If anyone from canada or if someone knows of a good reliable online store that accepts paypal that be cool too
 

nycrich

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Unplug that digital box and see if you have the same problem. Like I mentioned before my sat box was across the room causing the problem. Manufacturers(Asian manufacturers) save cost now by not enclosing RF circuits, oscillator circuits in enclosed shielding boxes on the pcb. It is cheaper/mass produce circuits using wave soldering and use plug in modules(tuner circuits, osc, etc) on the main pcb . As a result these devices transmit interference to sensitive or poorly made receiving devices.
 
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