Problem with Nagoya UT72G Antenna

[Smitty74]

I bought a mag mount antenna thats supposed to be specifically tuned for GMRS. I was having issues hitting repeaters with it, so I got a SWR meter and gave it a test.  It turns out that on the 2 meter ham band, its a perfect 1.0 to 1. On 462.600 mhz, its 1.5 and surprisingly on 467.600 its 4.0

Any advice on how to make this antenna work better on the repeaters, or an I stuck sending it back?

[Sshannon]

33 minutes ago, Smitty74 said:

I bought a mag mount antenna thats supposed to be specifically tuned for GMRS. I was having issues hitting repeaters with it, so I got a SWR meter and gave it a test.  It turns out that on the 2 meter ham band, its a perfect 1.0 to 1. On 462.600 mhz, its 1.5 and surprisingly on 467.600 its 4.0

Any advice on how to make this antenna work better on the repeaters, or an I stuck sending it back?

Do the instructions describe a method of tuning?  Maybe a set screw where the wire element inserts into a larger cylinder?

Without a VNA it’s difficult to exactly know. 

[WRPL700]

Are you sure you got the "G" version?  I have two of them and no problems with them.  I do not believe they are adjustable.

[SpeedSpeak2Me]

I'm have the exact same issue.  I have both the UT-72 and the UT-72G, and the 72G's UHF tuning appears to be in the 70cm band (centered on 440 MHz). With a Surecom SW-102 it's pretty much flat for 2m and MURS, about 1.1:1 for 70cm, almost 1.5:1 for GMRS simplex (462 MHz), and well over 2.1:1 on the repeater inputs (467  MHz).  Using a NanoVNA (calibrated 400-500 MHz using 401 data points) it is showing the same.  The "plain" UT-72 has better readings using both the meter and analyzer on the 462-467 MHz range than the UT-72G does, and it's quite disappointing, and somewhat frustrating.  I know others that have the UT-72G and they're tuned for center of the GMRS band, right around 464 MHz, and are less than 1.25:1 across the band.

Both came antennas came in identical bags, which do appear to be authentic Nagoya.  The UT-72G bag has a second sticker/label covering the original.  So UT-72 underneath, UT-72G on top.  They are basically identical expect the UT-72G's mast/whip is about 1" shorter than the UT-72's, which is about right for tuning up a 70cm antenna for 64cm, and for bringing a 2m antenna up to MURS.  Unfortunately neither are adjustable, unless you pull the rubberized protective cap off the whip and trim it back, then use something else to protect the end.

When testing with the Surecom I used a double-male PL-259 connector so that the transceiver was directly connected to the meter, and took out any possibility of the jumper cable being an issue.

Conversely I have a Diamond MR-77 that was tuned at > 1.3:1 for 2m and 70cm (center band for both) right out of the box.  Since it was an extra antenna, and tunable, I trimmed off about 20mm, and it is now centered at 464.500 MHz, right in the middle of the GMRS range.  I'm not worried about it on the VHF side, since it'll never be used for it.  But 2m is still workable, with the NanoVNA showing it to be centered at 147.500 MHz (upper end of the band), at about 1.2:1 with a nice shallow dip covering a bandwidth of 10-12 MHz.

[Smitty74]

thank you for the replies. Im sure I bought the "G" version. The good news is we bought this antenna for a caravan we have coming up and we are using a simplex channel, and those work fine. It will work for my need, just grumpy that I cant use a repeater with it (I tried, i either dont break squelch on the repeater, or my signal is terrible). Moving on I guess....  Thank you all.