Issue with through hole NMO mount in vehicle.

[WRTZ361]

I have been using a magnetic NMO mount on my vehicle for about 6 months. I did not like the cord showing so I decided to install a through hole mount in my roof since people are saying it is just overall better to mount this way. I installed it as according to the instructions and when I went to turn the radio on, it would not receive anything. My radio is capable of receiving the NOAA radio channels and I was planning on tuning into the strongest one for my area before I attempted to transmit. I assumed that if I did not set up the antenna correctly. I would damage my radio if I tried to transmit. The interesting part of this is that when I turned the vehicle off, the radio began receiving the NOAA channel very clearly for the 3 seconds it takes for it to turn off. I have no idea what this means. I believe I assembled everything correctly and I checked all of the connections at the radio itself. Any suggestions would be appreciated. 

[SteveShannon]

48 minutes ago, gortex2 said:

@SteveShannon as you are aware a properly installed NMO will not leak nor casue issues with resale trade in value. Other than my Jeeps every vehicle I have owned for 30+ years has had NMO mounts in the roofs. On my last F150 (2020) it had 6 NMO plus 2 GPS antenna's. My previous F150 (2019) had 4 mounts and the dealer never said a word when I traded it in. I put black NMO caps on them and I am sure no one even realized they were there. I've probably installed over a thousand NMO mounts sinces I've been in 2 way radio and in the end its always the right choice. As said I like the simple approach of not seeing cables, worring about cables etc. I drive thru car washes all the time and I'd definately not do that with a mag mount. I'm definately team drill it.... (btw...even my 2023 Scat has a NMO in the trunk for a 1/4 wave VHF...)

What do you mean by “team drill”?

What mount do you like?

[WRXB215]

20 minutes ago, SteveShannon said:

What do you mean by “team drill”?

@gortex2 I'm curious also. Do you mean like a unibit or one of those expensive dedicated bits?

[gortex2]

"Team Drill" - Meaning no mag mounts no glassm ounts, drill the darn hole.

As for my preferred NMO I use a mix of MSI and Laird. The Laird NMOKHF200NOCONN is my preferred mount but all my radios come with the motorola NMO and use them alot as well. I like the Laird as it is a sealed bottom and in the fringe areas on VHF simplex we are in for SAR they help that little bit. They are also ideal for antenna brackets on some Jeeps and are pretty water resistant vs standard NMO with the plastic cap on the bottom. All my Jeeps run that mount and a couple are almost 15 years old and stil lsweep fine. I do run the Laird NMOKHFDSTHK on one of my Jeeps with my BACK RACK as its a good 1/8" steel and a standard NMO wouldn't work. We run those same mounts in our command post as they are aluminum in construction (like an ambulance). 

In the end I've never had issues with either the MSI or Laird and still install MSI mountso n all our UHF stuff as thatsm ostly repeater or TLMR use and not simplex. 

[nokones]

I like the way my 5 Ft CB Firestik II antenna arcs back in the wind at 75 MPH on the Freeway.

[WRXB215]

35 minutes ago, gortex2 said:

"Team Drill" - Meaning no mag mounts no glassm ounts, drill the darn hole.

LOL! I'm quite embarrassed now for not getting that.  

[SteveShannon]

42 minutes ago, gortex2 said:

"Team Drill" - Meaning no mag mounts no glassm ounts, drill the darn hole.

As for my preferred NMO I use a mix of MSI and Laird. The Laird NMOKHF200NOCONN is my preferred mount but all my radios come with the motorola NMO and use them alot as well. I like the Laird as it is a sealed bottom and in the fringe areas on VHF simplex we are in for SAR they help that little bit. They are also ideal for antenna brackets on some Jeeps and are pretty water resistant vs standard NMO with the plastic cap on the bottom. All my Jeeps run that mount and a couple are almost 15 years old and stil lsweep fine. I do run the Laird NMOKHFDSTHK on one of my Jeeps with my BACK RACK as its a good 1/8" steel and a standard NMO wouldn't work. We run those same mounts in our command post as they are aluminum in construction (like an ambulance). 

In the end I've never had issues with either the MSI or Laird and still install MSI mountso n all our UHF stuff as thatsm ostly repeater or TLMR use and not simplex. 

Ahhh, Team “Drill It!”  Yeah, I missed that also.

[WRTZ361]

I got some ferrite cores that I can clamp on the cables and power wires at the recommendation of WRYZ926. I put 4 along the coax trying to place them evenly along it, and I put 2 on each end of the radio units power wires. I now am receiving all but 1 of the signal bars on my radio. There is a hint of static left, but it is a massive improvement. I am already looking at getting a 5/8 wave antenna, so that should improve things. How important is VSWR for mobile radios. In HT I never dealt with this so I never invested in the equipment. If it makes my equipment last longer or get better reception then I don't mind getting it, just not sure if its worth it. 

[WRYZ926]

Glad to hear the clamp on ferrites  helped you. And yes a 5/8 wave antenna will be better. Even a bottom loaded 5/8 antenna will work fine. The Tram 1174 is a bottom loaded antenna that is about 14-15 inches tall and works quite well for me.

You want to get the SWR at 2 or better. I had to trim my Tram 1174 and ended up getting SWR of 1.2 at 462.600 and 1.4 at 467.600.

[WRTZ361]

2 minutes ago, WRYZ926 said:

Glad to hear the clamp on ferrites  helped you. And yes a 5/8 wave antenna will be better. Even a bottom loaded 5/8 antenna will work fine. The Tram 1174 is a bottom loaded antenna that is about 14-15 inches tall and works quite well for me.

You want to get the SWR at 2 or better. I had to trim my Tram 1174 and ended up getting SWR of 1.2 at 462.600 and 1.4 at 467.600.

Can I just get an SWR meter and dummy load on amazon? Or do I need something of better quality to give me accurate numbers?

That was the antenna I was going to get based on the height. 36" for the other ones is just a bit tall for me. 

 

[WRYZ926]

You can use a SWR meter, but it won't tell you if the antenna is too long or too short. Best is to use a NanoVNA or an actual antenna analyzer. Maybe someone local will have an analyzer that you can borrow.

[WRTZ361]

1 minute ago, WRYZ926 said:

You can use a SWR meter, but it won't tell you if the antenna is too long or too short. Best is to use a NanoVNA or an actual antenna analyzer. Maybe someone local will have an analyzer that you can borrow.

Thank you for the suggestion I will ask around. 

[WRYZ926]

You're welcome.

[BoxCar]

10 hours ago, WRYZ926 said:

You can use a SWR meter, but it won't tell you if the antenna is too long or too short. Best is to use a NanoVNA or an actual antenna analyzer. Maybe someone local will have an analyzer that you can borrow.

Actually you can. If the SWR decreases at higher frequencies the antenna is short. Conversely, if the SWR decreases at lower frequencies you need to start trimming in 1/8 inch chunks.

[nokones]

1 hour ago, BoxCar said:

Actually you can. If the SWR decreases at higher frequencies the antenna is short. Conversely, if the SWR decreases at lower frequencies you need to start trimming in 1/8 inch chunks.

It's the same procedure as you would do with a CB antenna on channels 1 and 40.

[WRYZ926]

2 hours ago, BoxCar said:

Actually you can. If the SWR decreases at higher frequencies the antenna is short. Conversely, if the SWR decreases at lower frequencies you need to start trimming in 1/8 inch chunks.

While this is very true, I personally find it much easier to just use an antenna analyzer. All I can say is go with what method is easiest for you.

[SteveShannon]

13 hours ago, WRTZ361 said:

Can I just get an SWR meter and dummy load on amazon? Or do I need something of better quality to give me accurate numbers?

That was the antenna I was going to get based on the height. 36" for the other ones is just a bit tall for me. 

 

You can use an SWR meter, but the dummy load won’t do anything to hep you determine the SWR of the antenna. WRYZ926 is correct when he says that an analyzer (or a NanoVNA) is much easier.  An analyzer will show you the SWR over a range of frequencies.  To get similar results with an SWR meter you would have to transmit on a range of different frequencies and record the SWR for each frequency.  You’ll have to do that at a power level that is high enough to register on the SWR meter, not only for forward power but for reflected power. At lower power’s some SWR meters simply don’t register the reflected power and show an artificially low SWR.

The dummy load is useful if you need to test transmit on your radio, but because it replaces the antenna you can no longer see the reflected power coming from the antenna.  With most decent dummy loads you simply see an SWR of 1.0:1 full range.

If you do choose to use an SWR meter to analyze SWR across the entire GMRS range, be aware of the fact that power output changes for different channels on a certified GMRS radio and that the frequencies are not spread evenly or ordered according to channel number.

[WRUU653]

I would add most (at least the ones I’ve seen) GMRS antennas come pre tuned and would not likely benefit from trimming.

[WRYZ926]

Some antennas do need tuned while others come pre tuned. Even some pre tuned antennas still need adjusted a little. 

The Tram 1174 is an example of an antenna that does need tuned. Mine was actually tuned for the around 450 out of the box. I had to shorten it to get good SWR reading for GMRS.

[WRUU653]

29 minutes ago, WRYZ926 said:

Some antennas do need tuned while others come pre tuned. Even some pre tuned antennas still need adjusted a little. 

The Tram 1174 is an example of an antenna that does need tuned. Mine was actually tuned for the around 450 out of the box. I had to shorten it to get good SWR reading for GMRS.

I absolutely agree. However the Tram 1174 isn’t sold as a GMRS specific antenna (that I’m aware of) and my comment was about antennas sold for specifically for GMRS. My point being if you purchase an GMRS only antenna you likely won’t be trimming it. Also any antenna that has duel frequencies or broader frequencies will suffer in some areas so as you mentioned may need some tuning if you want something specific out of it. 
 

edit- I mentioned this not to be argumentative but rather to caution someone of trying to tune an antenna that likely wouldn’t need it and may ruin it. 

Edited October 29 by WRUU653
Additional info

[WRYZ926]

The Tram 1174 is sold as a GMRS antenna according to Buy Two Way Radios 

Quote

Tram 1174 is a Premium Coil NMO mount UHF gain antenna with a premium coil, metal base and top. It works with UHF business band and GMRS mobile two way radios.

https://www.buytwowayradios.com/tram-1174.html?___SID=U 

The Antenna Farm has the Tram 1174 listed under GMRS mobile antennas too.

https://theantennafarm.com/shop-by-manufacturers/manufacturer/tram/191-antennas/192-mobile-antennas/gmrs-antennas-mobile-base

I even had to adjust my Nagoya UT-72G mobile antenna.

There are tolerances in manufacturing so sometimes an antenna will need to be tuned even if it is just a little bit.

[WRUU653]

3 minutes ago, WRYZ926 said:

The Antenna Farm has the Tram 1174 listed under GMRS mobile antennas too

 

Yes it is but not specifically, it sold as “business band and GMRS mobile” which is a bit broader. But again I’m just cautioning someone that may not have your skills on “GMRS specific antenna” trimming. 

[WRYZ926]

Like I said, I had to trim my Nagoya UT-72G also. It was long from the factory and had SWR 2.2 on 467 MHz and 1.8 on 462 MHz. Yes that is doable but why waste power output if you can tune the antenna better. 

[WRUU653]

3 minutes ago, WRYZ926 said:

Like I said, I had to trim my Nagoya UT-72G also. It was long from the factory and had SWR 2.2 on 467 MHz and 1.8 on 462 MHz. Yes that is doable but why waste power output if you can tune the antenna better. 

I don’t disagree.

[WRXB215]

23 minutes ago, WRYZ926 said:

I had to trim my Nagoya UT-72G

I'm surprised at that. But then again, I suppose I shouldn't be. 

[WRYZ926]

30 minutes ago, WRXB215 said:

I'm surprised at that. But then again, I suppose I shouldn't be. 

I doubt that every single antenna is fully tested during production. So a few that needs tuned are going to slip out.

Most companies are only going to test a small portion of products of any given production run. Otherwise the overhead cost of Quality control would be higher which leads to higher consumer cost.