800 MHz vs. tri band antenna

[whelen1304]

I have a Uniden 996 XT that has been professionally programmed and have tried a couple antennas without great results. I first started with a window mount which as you all know is a waste of time and install then yesturday installed a Larson tri band 16" fender mount. Looks great but still not getting the results I am looking for. I took a Digital 800 MHz from the local PD that I am trying to receive and the radio they gave me works great.... (it is there's so it should) however the scanner in my car only got service in about half of my response district. My question is do you think if I replaced the tri band with a 800 MHz specfic antenna if I might get the reception I am looking for. I know I could only monitor within that band width but am willing to take that.

Thanks,
Mike

 

[W8RMH]

That will make a world of difference. Naturally if you want to receive signals on 800 mhz., an antenna tuned to that range will work best.

I listen to about 95 percent 800 mhz. trunked systems, and have 800 mhz. antennas on all my scanners. I get 5 bars most of the time.

...and I have to ask...exactly what is "professionally programmed" ?

 

[Rt169Radio]

Where did you place the 800mhz antenna? The Larsen tri-band antenna is a great antenna and its frequency range is 150-165/450-470/806-940 mhz,but its short in height so it has to be put some where high to get the best results.

You might not be getting great results due to it not being high enough on your car.But anyway a antenna tuned to the range that you want will of course work better

 

[n5ims]

I wonder if you may be having issues with Simulcast Distortion (Simulcast digital distortion - The RadioReference Wiki), which often happens when a scanner gets strong signals from multiple towers in a simulcast radio system. This gets worse as a better antenna is used since it makes the signals stronger, which can lead to more distortion issues. One of the real problems with simulcast distortion in scanners is that it appears to be a lack of signal strength causing the issue, although it's probably actually an excess of signal strength.

Some scanners include an attenuator that can be activated to reduce the signal levels as a way to cope with the issue. You may try activating yours to see if that helps. Other things to trying a portable scanner antenna on your 996XT inside the vehicle to see what that does. With it being inside and rather well shielded you may reduce the signal enough to help. It may even be worth removing the antenna entirely (if you don't have access to a portable's antenna or get no help that way) to see how much signal you get that way. Some folks have resolved the issue that way.

The digital radio you got from the local PD was specifically designed to handle a simulcast system and to correctly process the signals to prevent them mixing and causing the distortion issues. This can be done in a high dollar radio but not a relatively inexpensive scanner simply because the high dollar radio can afford to put in the high dollar circuitry needed to perform this function while the scanner makers can't and still meet the design price points. It's also much easer to solve the issue with a single band radio (like your PD's radio) than a very wide band one (like a scanner) simply due to the need to only handle a small range of frequencies. The few multi-band commercial radios handle the issue as well, but often have seperate circuits for each band (which is one reason they're so expensive).

 

[whelen1304]

That will make a world of difference. Naturally if you want to receive signals on 800 mhz., an antenna tuned to that range will work best.

I listen to about 95 percent 800 mhz. trunked systems, and have 800 mhz. antennas on all my scanners. I get 5 bars most of the time.

...and I have to ask...exactly what is "professionally programmed" ?

I bought my scanner through scannermaster.com and paid them to program the county in which my response zone is in. Thanks for the input. Do you by chance know what you would receivce (bars) if you switched the 800 MHz antenna with a tri-band?

 

[whelen1304]

Where did you place the 800mhz antenna? The Larsen tri-band antenna is a great antenna and its frequency range is 150-165/450-470/806-940 mhz,but its short in height so it has to be put some where high to get the best results.

You might not be getting great results due to it not being high enough on your car.But anyway a antenna tuned to the range that you want will of course work better

Thanks for the input. I only have a Larson Tri-band right now and it is mounted on the fender. There is already a VHF stealth antenna on the roof and I didn't want any more holes up there. Right now the scanner works great on the north side of my district (which is higher in elevation than the south).

 

[whelen1304]

mount

I forgot to mention that I am currently working with a Comet RS730 fender mount but not sure if this is the best application. I am restricted to mount anything more on the roof since I park in a garage. This is suppost to be a very good mount but I just don't really see how it grounds its self. Has anyone had any luck with this mount or can give advise on what would be best to replace? Thx

 

[whelen1304]

I forgot to mention that I am currently working with a Comet RS730 fender mount but not sure if this is the best application. I am restricted to mount anything more on the roof since I park in a garage. This is suppost to be a very good mount but I just don't really see how it grounds its self. Has anyone had any luck with this mount or can give advise on what would be best to replace? Thx

So in attempts to try and midigate this issue I replaced the comet mount with a metal L bracket direct into the fender to make sure there was an established ground.... Still no luck however. In fact, if anything it does a little worse. Any suggestions out there? I have also got a new 800MHz antenna and still doesn't seem to be doing the job. Any help out there would be greatly appreciated. Thanks!

 

[n5ims]

Since it's a trunk lip mount, the grounding is generally from the mounting set screws or simply though inductive coupling (like a mag-mount would provide) if the screws don't provide sufficient grounding.

 

[ScanTN]

I use this triband and it works great...

I am currently using this nmo triband antenna and it's working great. I use a lot of Laird's products and they all seem to work very well for what I try to do. I have it on an nmo trunk mount running one scanner currently. Looks great and if I ever need to remove it for some odd reason (e.g. carwash) then I have a small rain-cap cover that screws on in place of the antenna to protect the mount.

https://www.tessco.com/products/displayProductInfo.do?sku=15243

I agree with OHI063 though that a tuned antenna will typically work best and if my situation allowed then I would probably do the same. The problem for me is that I am monitoring multiple frequency bands and due to the current setup in the car it isn't practical to run multiple antennas with a distribution system. Eventually I will if I ever own and different vehicle.

 

[ScanTN]

Of course anything works much better than a glass mount. I used to run one of those and the results were terrible. For everyone else reading this - please do yourself a favor and use something other than a glass mount antenna. If you want excellent results you have to get the antenna outside the car.