[Scan-DC] Mobile Installation Interference

[Doug Kitchener]

Michael, many thanks, saved the the trouble of trying to find this - mucho appreciado!

The RadioReference source is a good idea too - I meant to take a look there and it sortof slipped my mind.

(But it's probably the evil fluorinated electric meters!)

:)

Regards,

Doug


>________________________________
> From: michael rumberg <m_c_rumberg at hotmail.com>
>To: Doug Kitchener <oldsdoug at yahoo.com>; "scan-dc at mailman.qth.net" <scan-dc at mailman.qth.net> 
>Sent: Sunday, April 7, 2013 10:03 AM
>Subject: RE: [Scan-DC] Mobile Installation Interference
> 
>
> 
>I dont know in particular (your email got my curiousity up on special package) but I found this PDF from GM which indicates they have done radio suppression mods and gives some of the tech specifications
>http://www.chevrolet.com/content/dam/Chevrolet/northamerica/usa/nscwebsite/en/Home/Ownership/Manuals%2520and%2520Videos/02_pdf/2k13tahoepolice.pdf
>
>and there is this thread (and probably others at RR)  http://forums.radioreference.com/pictures-your-shack-mobile-setup/249052-2013-tahoe-build-ssv-ppv-5w4.html
>
> 
>
>> Date: Fri, 5 Apr 2013 18:13:03 -0700
>> From: oldsdoug at yahoo.com
>> To: scan-dc at mailman.qth.net
>> Subject: [Scan-DC] Mobile Installation Interference
>> 
>> Need some help, list - I have a 2012 Tahoe; put my Radio Shack PRO-197 in it and I got occasional bursts of interference when using the radio.  Fiddled around with it and discovered that this is occurring even when the vehicle's engine is _off_.  I don't have this problem with the same radio when using it in other vehicles  (e.g. 2001 Impala).  Even at that, I wondered if it might have something to do with the technology of the radio itself, so today I tried the Uniden BC-796 - same problem.  Again, this is occurring with the engine not running, is in the form of a popping noise or a fluttering noise.  I noticed it today on a vhf frequency with the Uniden... not sure whether it's doing it with 800 MHz digital systems or what (still gathering data); but the fact that the Uniden was getting it as well as the Radio Shack was a bit of a surprise.
>> 
>> All I can figure is that the "BCM" (Body Control Module) may be the culprit, as I'm getting this even with the engine off, even though it sounds like "ignition" noise.
>> 
>> 
>> First question:  First, does anyone here happen to be familiar with mobile installations of professional two-way equipment?  A lot of jurisdictions around here are using Tahoes for police and fire work... wondering if anyone has heard anything about this or run into this problem.  Of course there are Tahoes and Suburbans that are marketed for "special use" or police use, not sure if they have electrical system mods other than HD charging systems, but I'm looking into that.  Mine is a "civilian" vehicle, the dealer wouldn't sell me a 5W4 (a bit to my surprise).
>> 
>> Second question:  Besides connecting the +12V to the radio directly to the vehicle battery and shielding it, and grounding the radio, can anyone think of anything else I might do?
>> 
>> The antenna setup I'm using is a bit of a jury-rig... it's a suction-cup "windshield mount" thing that came with a BC-350 that I have.  The radio is mounted on a carpet-covered piece of plywood between the front seats, and the antenna is stapled to the underside of the  plywood (yeah, I know).
>> 
>> Things I'm going to try:
>> 
>> Using a back-of-set antenna just to see if that makes any difference;
>> Running a +12V lead directly from the vehicle battery to the radio (first unshielded as I don't think I have any shielded wire around here);
>> Rigging up some sort of temporary 12V supply, independent of the vehicle's power, to see if any effect;
>> Trying one of the portable scanners to see how they behave.
>> 
>> Anybody have any thoughts, ideas, suggestions, questions?  Thanks!
>> 
>> Comment:  I also have a 2001 Tahoe that I've been happy with; the new one was a planned replacement for the '01.  I saved for three years to special-order the new one and so far, it's been a significant disappointment.  This radio business is just a small part of that and the old one is a much better vehicle in almost all aspects.    If anyone is considering purchasing a new Tahoe / Suburban / Yukon one and wants to know the whole story, let me know off-list.  If I had it to do over, I almost certainly would do the same thing, but note that I'm in the car hobby and can be very blind about them because of that.  I would probably not recommend the purchase of a Tahoe or Suburban to someone who isn't wedded to General Motors products.
>> 
>> Regards,
>> 
>> Doug
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