How Strong of a Signal Will Damage SDS200?

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Kaleier1

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There is one trunked system I want to listen to that I am not able to pick up with the included antenna. I bought a 9 element 806-960Mhz 13 dbi yagi antenna and indoors I can barely get the system but the control channel signal is too weak to be reliable.

I am going to put the yagi up on my roof where I have direct line of site to this weak system several miles away.

The problem is, I also listen to the Highway Patrol and one of their transmitter sites is directly next to the one I am trying to receive but instead of several miles away it is only one mile away from my house. The FCC license info shows an output of 100 watts from the Highway patrol site.

So with a 13 dbi antenna pretty much pointed directly at a the Highway patrol site even with the 20 db attenuation of the SDS200 turned on, is this going to damage the SDS200 front end?
 

jonwienke

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No. If it was within a few hundred feet, possibly. A mile away, it might cause interference, but it's not going to damage anything.
 

ka3aaa

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the only to possibly blow out the sds200's front end is to have a transmitter within a few feet like two or three feet of the sds200.

secondly just getting the antenna outside and up in the air like 20 feet will make a big difference in reception.
 

Hit_Factor

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I have a 100 watt amatuer radio (vhf/uhf) and SDS100 in my F350. The antennas are mounted one on each side of a Back Rack.

At home my SDS100 is connected to a discone 25-ft (via multicoupler) that's underneath my 1500 watt amatuer radio (HF) antenna - 40 ft..

I have a RF limiter between the discone and multicoupler. Right or wrong, I ran without the limiter for about a year.
 

jonwienke

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If you have a question, get a watt meter and a dummy load, connect the dummy load to the output side of the watt meter, and your scanner antenna to the input side. Key up your transmitters, and see how much RF power feeds into the scanner antenna. 250mW or less is not damaging (ask me how I found that out :D ), but I'd be very cautious about exceeding that.

Antennas in different bands couple far less efficiently, so a HF transmitter isn't going to feed much RF into a VHF or UHF antenna, even if it's running a lot of power. The main concern is same-band transmissions.
 

Kaleier1

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Thank you all for the replies. I put the yagi on the roof and it does make a huge difference. It's a 800-900 MHz yago but the weather station frequencies at 162 come in loud and clear where I couldn't receive them with the included SDS200 antenna unless I moved the SDS200 around and then it was weak and scratchy.
 
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