Using Onstar for a simple scanner antenna

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sprite1741

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I have no use for Onstar and don't subscribe so I made up a pigtail for my 2005 GM Onstar antenna and it's excellent on 700/800 Mhz, seems fine on UHF and VHF. The antenna lead is just a push on coax connector on the back of the Onstar. Since I am mounting in dash, the Onstar was right there, I only needed a few inches to match up the connectors. Just need some coax with an F connector on one end and a BNC on the other to the scanner. F to F barrel connects the original antenna wire to the pigtail. No holes, no magnets, and no extra antennas. Hope this helps someone that may want to use the existing Onstar antenna for a roof mount scanner antenna. No cost either, had the parts for the jumper laying around. 5 minute install and non destructive.
 

jonwienke

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Onstar uses frequencies in the 800MHz range, so reception in that area will be decent. Reception in other bands below that range will work, but be far from ideal (especially VHF).
 

ka3aaa

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That Onstar antenna and your regular am/fm antenna are super nice disguise antennas for scanners.

Nobody would ever think that you have a scanner installed in the car and will work great on the scanner.
 

nd5y

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I think all the major carriers still have 800 mHz capability though they don't normally sell 800 mHz phones. Also, I think their 800 mHz is strictly analog.
Analog was discontinued in 2008.
Most modern phones cover multiple bands including 800.
You can look up FCC licenses to find out which carriers use which bands in your county.
 

sprite1741

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The big deal for me was getting the mount working. I didn't want an extra antenna on this car. 700 Mhz is 99% of what I listen to at home . I do pick up the weather ok with this antenna even though the transmitter is 50 miles from here. It's on a mountain top. There are other whips available. I found a 9 inch and a 16 inch on ebay, but going to make a trip to the junk yard and see if I can find an larger antenna for traveling where I may want VHF and UHF reception. The whip just unscrews. Never had luck with glass mounts on 800 mhz and magnet mounts damage the paint when they get moisture under them.
 

slapshot0017

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This is really interesting. I drive a VW and they have this useless car connect program just like onstar. I wonder if I can find that cable and use it as an extra antenna.
 

rdxny

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My car has XM and AM/FM whip on top, looks a lot like this one. But I can't use the XM antenna (the base) as a scanner antenna (2.3GHZ), so I was thinking about using the AM/FM part (the 6 inch or so whip) as a scanner antenna. But I still want the AM/FM function, so does anyone think that a splitter put behind the radio somewhere might adequately service both AM/FM and also a bcd325p2 for vhf and uhf freqs?
 

marksmith

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My car has XM and AM/FM whip on top, looks a lot like this one. But I can't use the XM antenna (the base) as a scanner antenna (2.3GHZ), so I was thinking about using the AM/FM part (the 6 inch or so whip) as a scanner antenna. But I still want the AM/FM function, so does anyone think that a splitter put behind the radio somewhere might adequately service both AM/FM and also a bcd325p2 for vhf and uhf freqs?
My guess is you would be just as well off with the standard antenna on the radio.

Mark
536/436/WS1095/HP1/HP2/996T/996XT/996P2/396XT/325P2/PSR800/15X/others
 

rdxny

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Probably, just thought getting the antenna outside the car would be useful despite the split, Maybe:)
 

DJ11DLN

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Interesting. I had a similar idea for my '08 Trailblazer. But when I connected the scanner, I had very low signal strength on 800. In fact, the scanner laying there on the floor (my Onstar module is, or rather was, under the RR seat) with the RS800 on it had far better signal strength than when connected to the coax. Perhaps the antenna is defective...mine is the shark fin type.
 

sprite1741

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Autozone and O' Reilly have quite a selection of different whips. Any universal screw mount fits. I am trying a 7 inch one now and ordered a 16 inch off ebay. The 7 inch antenna is working nicely on UHF and 7/800 The one I have now is silver and has a removable threaded whip, which can be upgraded. All antennas are a compromise but easy to experiment with this set up.



 
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