800mhz antenna options - input needed

V1Jake

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Hey guys. Need some input on an 800mhz antenna for a handheld Uniden scanner.

I purchased a 1/4 wave Tram antenna (on a Browning 5" mag mount) for now and the range/reception is good but I want something better to reduce static and get even more range.

The antenna will be mounted on a browning NMO trunk lip mount next to my Larsen 150/450/800 on another trunk lip mount. Both antennas will be spaced evenly along the trunk.

Current Tram antenna:




All frequencies I am scanning is from 850-853mhz

Larsen option 1: NMO3E800B - there is also a 825mhz version
3.2 db gain, 806-866 range, 13.5" whip


Larsen option 2: NMO3H800B
3.2 db gain, 806-866 range, 13.75" whip


Larsen option 3: NMO5E825B
5 db gain, 825-896 range, 17.2" whip (a bit too long for my liking due to it hitting the roof)



I looked at the Laird options and they are about the same.
 
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dchemist

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I had this conversation with the radio guy at work last year. His advice, "Don't waste your money for less than 5 db gain."
 

V1Jake

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I had this conversation with the radio guy at work last year. His advice, "Don't waste your money for less than 5 db gain."
Solid advice. I do have some left over 3m clear brake that I cut cut into a half in sliver to protect the roof against the longer 17" antenna if need be.
 

JFR

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This is what I run on my agency APX8500 on several state's 800 TRSs when I need gain. Otherwise I run a lowprofile 1/4 wave.

Laird Model # B8065C

-JR
 

V1Jake

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This is what I run on my agency APX8500 on several state's 800 TRSs when I need gain. Otherwise I run a lowprofile 1/4 wave.

Laird Model # B8065C

-JR
How is the reception with it? Looks like two votes for a 5db gain antenna. Looks like I will get the one with that gain over the 3.5. Thanks
 

JFR

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I don't notice the difference between 3 and 5db gain. Truthfully, you'll only notice much of a difference at the fringe of reception. There is a difference between the unity-gain quarter-wave and the big whip starting at the outer 1/3 of reception area. Don't feel like you're giving up a whole lot if you end up with a 3db antenna.

-JR
 
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V1Jake

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I don't notice the difference between 3 and 5db gain. Truthfully, you'll only notice much of a difference at the fringe of reception. There is a difference between the unity-gain quarter-wave and the big whip starting at the outer 1/3 of reception area. Don't feel like your giving up a whole lot if you end up with a 3db antenna.

-JR
Appreciate the response JR.

I will try to grab some dashcam footage from today so you can hear some of the received signals to see if they can be more clear.
 

JFR

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Last thought- I occasionally run the 5 db gain Larsen on my Uniden 996XT. It will overload the front-end of the scanner when you pass near a low cell site such that the 800MHz LMR control channel will be lost momentarily. Still happens with 3 db, but just not as long.
 

InsipidMonkey

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What cable are you using and how long is the run? Coax losses increase with frequency - for example 18ft of RG58 will lose about 2.4 dB @ 850 MHz, negating any gain at the antenna.

I wonder if something like this Remtronix 800 MHz whip would work better?
 

JFR

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What cable are you using and how long is the run? Coax losses increase with frequency - for example 18ft of RG58 will lose about 2.4 dB @ 850 MHz, negating any gain at the antenna.

I wonder if something like this Remtronix 800 MHz whip would work better?
The metal skin of your car is worth 6-8 dBd of attenuation. It's important to have the receiving antenna outside of the vehicle, even with a reasonable bit of cable loss.

(This in-car attenuation value @ 800 MHz is first hand experience seen during my 18 year run as an RF Engineer for AT&T Wireless)
 
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dchemist

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The metal skin of your car is worth 6-8 dBd of attenuation. It's important to have the receiving antenna outside of the vehicle, even with a reasonable bit of cable loss.

(This in-car attenuation value is first hand experience seen during my 18 year run as an RF Engineer for AT&T Wireless)
What about the ground plane of a lip mount vs a mag mount?
 

V1Jake

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What about the ground plane of a lip mount vs a mag mount?
For my trunk lip mount I have two wires running around/from the two mounting screws and running to the trunk where I drilled a hole, sanded around the hole and connected the two wires to a nut/bolt. No issues with my Yaesu transmitting/receiving. I plan to do the same with the second trunk lip mount for the 800mhz antenna.

@InsipidMonkey The browning mag mount I am using now is around 11 feet. The amazon ad is incorect.

browning WSPBR10353
 

V1Jake

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What cable are you using and how long is the run? Coax losses increase with frequency - for example 18ft of RG58 will lose about 2.4 dB @ 850 MHz, negating any gain at the antenna.

Revisiting this thread since I'm moving to NJ in two months and I'll be heading up from southern NJ to Queens every day. With the 3db antenna I feel like I'm missing range so I'm going to get the 5db version and compare. If it's the same I'll just use one of them at home on a mag mount.


My current cable is a Tram 1245B 17feet with a right angle SMA connector.
 
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Deacon

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Revisiting this thread since I'm moving to NJ in two months and I'll be heading up from southern NJ to Queens every day. With the 3db antenna I feel like I'm missing range so I'm going to get the 5db version and compare. If it's the same I'll just use one of them at home on a mag mount.


My current cable is a Tram 1245B 17feet with a right angle SMA connector.
That antenna will work well for transmissions within that specific frequency range. Are you certain that frequency range is what you’re looking for? For scanner purposes you’re almost certainly better off with this:


Where is your NMO mount drilled? How much coax do you have cooked up? And in what vehicle? Can you share a pic of the roof or trunk where it’s been drilled? Tram is generally low on the middle tier of equipment, and you don’t save much over name-brand mounts, but generally speaking it should be fine.
 

JFR

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In my experience in swapping among unity, 3dB, and 5dB antennas on my setup..... The higher gain antenna you use, you will find that cell towers will have an increasing negative effect on the 800 MHz public safety band performance of your scanner. 800 MHz cell transmitters will overload the frond end of a Uniden scanner as you drive by. You will typically lose reception of the public safety control channel within a 1/4 mile radius of the cell site. The scanner is simply deaf (overload condition). And there are a LOT of cell sites in an urban/suburban environment that you don't physically see "yelling" at your scanner..lol.

This is less prevalent on the highways where the towers are spread out, but note that most cell sites in rural areas are near the highway so they present a very strong signal to your receiver.

Gain is a trade-off in this case, as the gain of a given antenna also increases the interference, not just the intended signal.

A note on my experience- I was an Cellular RF Engineer for AT&T Wireless for 18 years and now work with communications systems for the federal gov't. Additionally, I've been in the scanning hobby since I was 10.

Good luck!
-JR
 

V1Jake

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In my experience in swapping among unity, 3dB, and 5dB antennas on my setup..... The higher gain antenna you use, you will find that cell towers will have an increasing negative effect on the 800 MHz public safety band performance of your scanner. 800 MHz cell transmitters will overload the frond end of a Uniden scanner as you drive by. You will typically lose reception of the public safety control channel within a 1/4 mile radius of the cell site. The scanner is simply deaf (overload condition). And there are a LOT of cell sites in an urban/suburban environment that you don't physically see "yelling" at your scanner..lol.

This is less prevalent on the highways where the towers are spread out, but note that most cell sites in rural areas are near the highway so they present a very strong signal to your receiver.

Gain is a trade-off in this case, as the gain of a given antenna also increases the interference, not just the intended signal.

A note on my experience- I was an Cellular RF Engineer for AT&T Wireless for 18 years and now work with communications systems for the federal gov't. Additionally, I've been in the scanning hobby since I was 10.

Good luck!
-JR
Thank you so much for the reply! I really appreciate you taking the time to explain the differences and the effects of the higher gain antenna.

This morning I did look at the tower locations and they look to be close to the highway. I put the approx location of the highway I drive on so you can see the relative location. Do you see them being a problem? I circled the three towers nearest the highway I travel on.
 

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InsipidMonkey

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I didn't realize you were trying to scan NJSP! The system is very strong with good coverage, I've used a paperclip successfully. As @JFR said, an antenna tuned to 800 MHz may be counterproductive. I'd certainly wouldn't spend money on a new antenna, whatever you have currently will be fine.
 

V1Jake

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I didn't realize you were trying to scan NJSP! The system is very strong with good coverage, I've used a paperclip successfully. As @JFR said, an antenna tuned to 800 MHz may be counterproductive. I'd certainly wouldn't spend money on a new antenna, whatever you have currently will be fine.
The scanner is solely for NJSP. I have a 3db antenna on an nmo mount right now. It does well but sometimes static when I pick up a signal and they're talking.

I also have a 1/4 wave I used before the 3db I can give a shot again today but it would be below the roof line of the car since the mount is on the trunk.
 

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