HT mobile set-up expectations

[SteveShannon]

7 hours ago, WSAN206 said:

Took the roof rack off and slapped it right in the middle of the roof.  Tried to reach a repeater about 31 miles away and wasn’t able to ping  it (no mic attached) .   Stepped out and put my 771g on and instantly got a response from the repeater.   Gotta be something jacked up with the adapters where it necks down to my HT or somewhere in the coax itself.  I’ll wait and check Tuesday when my meter comes.  So frustrating.  

I would agree that it sounds like it’s something to do with either the feed line or the antenna.  It could be that the antenna has a high SWR on the repeater frequency but it could also be that the cable or the mount are damaged or that the antenna itself is broken. I had a capacitor fail in an antenna once and it made the antenna go high SWR.

Do you have access to a different roof mount antenna you can try?

I use an MXTA26 antenna on a Midland NMO mount. My roof rack doesn’t seem to bother it in any detectable way.

A few other random thoughts.  An SWR meter shows the SWR of the antenna and feedline combination.  It doesn’t show where the antenna is resonant.  It’s very commonly thought that resonance is where the SWR is lowest, but it’s not true.  A reasonably low SWR (usually described as 2.0:1 or better) is helpful.  Cell phone antennas frequently have SWRs around the 4 or 5 to 1 and they do fine, but I have tried to use a GMRS antenna (the MXTA26) on 2 meters, a frequency that wasn’t even considered when designing the antenna and couldn’t be heard 6 blocks away with 20 watts.

 

[WRYZ926]

A NanoVNA or antenna analyzer is what you need to see where the antenna is resonant. I know not everyone has those or can afford an antenna analyzer.

First check the coax cable and all connectors/adaptors to make sure they are good.  I would try a different antenna on your mag mount if you can. That will help eliminate the antenna or mag mount as the problem.

[WSAN206]

4 hours ago, Sshannon said:

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Do you have access to a different roof mount antenna you can try?

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I wonder if my antenna may be a UT72 instead of 72g.  Maybe mis-packaged?   
 

I actually do have UT72 (non-g) that I bought by mistake first and haven’t returned it yet.  I’ll check and see if they look the same.   I assume one should be slightly different? 

[SteveShannon]

7 minutes ago, WSAN206 said:

I wonder if my antenna may be a UT72 instead of 72g.  Maybe mis-packaged?   
 

I actually do have UT72 (non-g) that I bought by mistake first and haven’t returned it yet.  I’ll check and see if they look the same.   I assume one should be slightly different? 

The GMRS antenna might be slightly shorter. 

[WSAN206]

3 hours ago, WRYZ926 said:

A NanoVNA or antenna analyzer is what you need to see where the antenna is resonant. I know not everyone has those or can afford an antenna analyzer.

First check the coax cable and all connectors/adaptors to make sure they are good.  I would try a different antenna on your mag mount if you can. That will help eliminate the antenna or mag mount as the problem.

My cousin has a nanoVNA.  I might see if he can help me - looks beyond my skills 

[SteveShannon]

44 minutes ago, WSAN206 said:

My cousin has a nanoVNA.  I might see if he can help me - looks beyond my skills 

Nanovna Saver is a software program that makes the nVNA much easier to use and visualize antenna characteristics. 

[WSAN206]

Ok - updates.  I received a replacement antenna from Amazon tonight after explaining  my situation to the seller (btech).  Also recieved swr meter so decided to test the current setup and I’m shocked.  
these are on channel 1, 15, and 30.   Does this seem right? Higher wattage than expected from my baofeng uv-9G  too.  

[SteveShannon]

Yes

[WSAN206]

Installed the new antenna tonight.  I think it’s better - still the same swr reading (1.00 - 1.02).  I think I’m getting a lot of popping and scratching from all the overhead lines around here.   Seems to work well in the middle of my yard and I’m reaching repeaters 45 miles away.   I’m done with the antenn for now. 
 

really appreciate all the help guys!!  

[WRYZ926]

Those SWR and power reading look good.

The popping and scratching can definitely be from the power lines, especially if they are high power transmission lines. Or it could be obstructions between you and the repeater too. I would still double check all coax connectors just to make sure.