GMRS Radio Question

[Dougstdig]

Buy a real quality antenna

Such as…???

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[TwoSerious]

Looks ok but I would get that antenna up in the clear. You could probably get away with a trunk lip mount between the hood hinges as the antenna is short and should not block any view out the front windshield. Your range would be improved in all directions.

I agree with this as well. You pretty much block any radiation your antenna has on the vehicle side. I have mine mounted on a hood mount I made and its been doing pretty well.

 

[ArmyMP]

Such as…???

Join a GMRS group and ask. I run a tri band larsen 19" antenna. It's 5/8th wave.

Do you have your GMRS License?

 

[Dougstdig]

Join a GMRS group and ask. I run a tri band larsen 19" antenna. It's 5/8th wave.

Do you have your GMRS License?

No not yet

 

[Radio Guy]

Join a GMRS group and ask. I run a tri band larsen 19" antenna. It's 5/8th wave.

Do you have your GMRS License?

The Larsen Tri-band is a 1/4 wave equivalent on VHF/UHF and 800MHz and is actually a little worse than a full size 1/4 wave on any given band. I have several. An actual UHF 5/8 wave is a slight improvement over a 1/4 wave whip and even more over a short stubby and its not all that big, maybe 10 or 11" tall.

 

[ArmyMP]

The Larsen Tri-band is a 1/4 wave equivalent on VHF/UHF and 800MHz and is actually a little worse than a full size 1/4 wave on any given band. I have several. An actual UHF 5/8 wave is a slight improvement over a 1/4 wave whip and even more over a short stubby and its not all that big, maybe 10 or 11" tall.

My triband larsen is 19" so it is a true 5/8ths

 

[Radio Guy]

My triband larsen is 19" so it is a true 5/8ths

The Larsen Tri-band is advertised as a 1/4 wave unity gain on each of its three bands and its 16.5" tall not 19". 19" is not 5/8 wavelength on 462Mhz its more like 15" if your talking a single band UHF 5/8 wave antenna but that gets shortened to about 10-11" due to the single turn matching coil in the base because a 5/8 wave antenna is not a 50 ohm antenna and it needs additional matching.

The Larsen Tri-band is ok to use on GMRS but its a compromise antenna made to cover VHF/UHF and 800MHz and will have less performance than a single band UHF antenna of similar size.

 

[TwoSerious]

The Larsen Tri-band is advertised as a 1/4 wave unity gain on each of its three bands and its 16.5" tall not 19". 19" is not 5/8 wavelength on 462Mhz its more like 15" if your talking a single band UHF 5/8 wave antenna but that gets shortened to about 10-11" due to the single turn matching coil in the base because a 5/8 wave antenna is not a 50 ohm antenna and it needs additional matching.

The Larsen Tri-band is ok to use on GMRS but its a compromise antenna made to cover VHF/UHF and 800MHz and will have less performance than a single band UHF antenna of similar size.

I have a Larsen triband that I've used before and would be better than the low profile but as stated it's a compromise and it performs okay. I would opt for a more specific antenna for the band especially if that's all you're running. I've heard some decent reviews of the rfmax grms antenna I forget if they offer more than one type for grms but I've heard they perform well. If I ever get my hands on one I'll report back.

 

[Kballs]

Interesting, the static only comes in when my Jeep is running. Frustrating to say the least.

 

[Josh00333]

99.999999999% your getting power interference form the alternator/charging system.

How do you have the radio wired?

If it's not a direct line off the battery pos and ground post in the engine bay; change it. 99% likely this will fix your issue.

I had interference on chan 19-22, by going direct ground to the main ground and direct hot to the battery it solved my issues 100%.

I tired the ground post in the cab and running hot off the ign feed for the aux switches and it didn't work.

Interesting, the static only comes in when my Jeep is running. Frustrating to say the least.

 

[Kballs]

I tired the ground post in the cab and running hot off the ign feed for the aux switches and it didn't work.

That’s exactly how mine is wired. I’ll give this a shot.

 

[Radio Guy]

That’s exactly how mine is wired. I’ll give this a shot.

If the interference is coming in on a specific channel and the rest are clean then its probably not the power leads and its being picked up by the antenna. This is where a mag mount or other antenna can be used as as a probe to sniff out the source.

 

[TwoSerious]

Wouldn't hurt to run power to battery and ground to chassis ground for the battery. Don't know if that will solve your issue. Generally when you have a noise from the vehicle charging system you'd hear a whine that corresponds to engine RPM. It is good practice to run directly to the battery for power and to the battery ground to the vehicle but not directly to the battery negative. If you're running your radio off the Jeep Aux switches you are actually pretty much running to battery as I believe its battery to relay to output.

 

[Radio Guy]

I have a couple of radios in my JT and have tuned in all kinds of stuff from HF to CB to 2m and 70cm amateur and GMRS and have had zero interference from anything when the engine is on or off. Spark plug noise will be most prevalent at HF and CB and rarely goes into the UHF region. My JT is amazingly quiet on all bands. I have two antennas on NMO mounts on the hood, one NMO mount behind the rear window on the upper bed rail and one mount on the driver side upper bed wall just behind the rear wheel. I've tried both radios with antennas at all locations and no noise anywhere.

So far all my permanent radios are mounted under the rear seat where I have 4ga wire running through the floor into the frame then up into the engine compartment next to the battery and they connect to the battery hot via a 150 amp fuse and the ground goes to a chassis ground stud next to the battery. Not sure if this power setup is less prone to noise or not and I have run a radio temporarily from the AUX power switched cables under the glove box and have not had any noise on that line either, but I forget what bands I was using on that radio.

I would beg, borrow or steal a mag mount UHF antenna and move that all around the vehicle and under the hood sniffing for the noise. You should be able to get an idea where its coming from and determine if a different antenna location will reduce or eliminate the noise. For example, if the noise is coming from something under the hood your current antenna is very close to that. Maybe moving the antenna to the upper rear bed wall just below the back window might not pick up the same noise.

If all else fails, bring your truck to So Cal and I'll find and fix the problem.

 

[Kballs]

I have a couple of radios in my JT and have tuned in all kinds of stuff from HF to CB to 2m and 70cm amateur and GMRS and have had zero interference from anything when the engine is on or off. Spark plug noise will be most prevalent at HF and CB and rarely goes into the UHF region. My JT is amazingly quiet on all bands. I have two antennas on NMO mounts on the hood, one NMO mount behind the rear window on the upper bed rail and one mount on the driver side upper bed wall just behind the rear wheel. I've tried both radios with antennas at all locations and no noise anywhere.

So far all my permanent radios are mounted under the rear seat where I have 4ga wire running through the floor into the frame then up into the engine compartment next to the battery and they connect to the battery hot via a 150 amp fuse and the ground goes to a chassis ground stud next to the battery. Not sure if this power setup is less prone to noise or not and I have run a radio temporarily from the AUX power switched cables under the glove box and have not had any noise on that line either, but I forget what bands I was using on that radio.

I would beg, borrow or steal a mag mount UHF antenna and move that all around the vehicle and under the hood sniffing for the noise. You should be able to get an idea where its coming from and determine if a different antenna location will reduce or eliminate the noise. For example, if the noise is coming from something under the hood your current antenna is very close to that. Maybe moving the antenna to the upper rear bed wall just below the back window might not pick up the same noise.

If all else fails, bring your truck to So Cal and I'll find and fix the problem.

I had some spare time yesterday and roughly wired from the battery/grounding post into the cab as a test. You were 100% correct that it would not make a difference.

Since Illinois is finally seeing better weather today (SoCal sounds better), I’ll get the mag mount out and see if I can narrow it down. I’m also moving the antenna forward to the next bolt hole to get away from that a-pillar a little more.

Seeing as I’ve gone full send on this project, I ordered up a Laird BB4502N. I’m determined to make this work properly ?

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