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Need help on interference issue

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timkilbride

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My dad keeps get interference on two frequencies, 155.895 and 160.920. I have attached a .zip file of the MP3. It even sounds like there are two sources of the interference. The radio the recording is from is a CDM1250. He also has a 996t that has never received it. The Maxtrac got it a little bit this past summer but is normally quiet, interference wise.

Thanks

Tim
 

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ScannerSK

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That sounds like interference generated by a TV antenna amplifier. Possibly a neighbor has a TV antenna amplifier that is malfunctioning?

Shawn
 

Rt169Radio

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It might have something to do with TVs because its in the VHF high mhz area.Although I thought TV interference would be rare because of the digital switch over.How long has it been happening?
 
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burner50

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Didn't you install an antenna with a preamp at your dads place a couple years back?
 

mm

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Or a plasma TV, an electric lawn mower charger, electric leaf blowers chargers, electric snow blower charger or a PC router, these are all home appliances that I have identified to emit similar noises from under 500KHz to over 225 MHz.

This wonderful noise is of course the courtesy of the FCC's lax regulation and kissing manufacturers rear ends just so they can sell any kind of crap Mfg'd in China.

After all what would we watch Macey's Xgiving day parade on but a wideband RF noise generating TV made in China and what would we cut our grass with, what with all of the Green initiatives outlawing gas mowers, but an electric induction charging mower made in china of course.

This noise has been found to either totally block various commercial and consumer receivers front ends in the case of the electric lawn mower charger and plasma TV's of FM, P25, AM, SSB,amtor,... equipment and opening the squelch in AM and FM receivers when emitted by PC routers.

I'd bet the reason that the 996 doesn't receive it while other radios do to varying degrees is because of the sensitivity difference of each radio.

For 12 dB sinad, the 996 sensitivity is around .4 to .45 uv or even worse, the maxtrac should be close to .3 -.35 uv and if I remember correctly the CDM is closer to .20 - .25 uv.


OK I'm off of my RF soapbox rant for now so that I can go and adjust my antenna phasing/nulling box to get rid of the neighbors Plasma TV noise and work some 10 meter DX.
 

timkilbride

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Didn't you install an antenna with a preamp at your dads place a couple years back?
Last year I installed half of a DB-224 and a Electroline EDA-UG 2402 or 2802 drop amp. Can't remember which model since I did two installs with each model.

It might have something to do with TVs because its in the VHF high mhz area.Although I thought TV interference would be rare because of the digital switch over.How long has it been happening?
It started sometime this past late spring or early summer.

That sounds like interference generated by a TV antenna amplifier. Possibly a neighbor has a TV antenna amplifier that is malfunctioning?

Shawn
The whole town doesn't have a cable system so its either OTA or some sort of dish network if you want to watch TV. The closest network TV transmitter is 70.5 miles away, so anyone using OTA would probably have a amp.

I'm just trying to plan ahead so maybe I can troubleshoot this problem when I get back to his house next month. When it was happening this past summer, I shut down the breakers in his house with no luck.

Tim
 

ScannerSK

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If you have a scanner that is capable of wide FM (WFM) mode using it may help to locate the source. It sounds as if you may have to drive/walk around a little in search of the interference.

Shawn
 

DickH

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If you have a scanner that is capable of wide FM (WFM) mode using it may help to locate the source. It sounds as if you may have to drive/walk around a little in search of the interference.

Shawn
And if you remove the antenna and still heart it, you know it's close.
 
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