ljh505 Posted November 4, 2020 Report Share Posted November 4, 2020 I have a Midland MXTA26 obtained from the official Midland store on Amazon. It is mounted on a Diamond K400 series trunk lip mount on a small coupe. It resonated around 481 MHz out of the box. Extending the whip as much as possible while still maintaining a grip via the 2 set screws in the whip base, the lowest I can get the resonant point is 478 MHz. It is worse than 1.8:1 SWR at the GMRS 463 MHz frequencies. So I'd say the antenna is cut a bit short at the factory for certain mobile mounting configurations, and there isn't a way to lengthen it. I'm keeping it as a backup antenna. I picked up a tunable (cut to tune) antenna from a different manufacturer from a local land-mobile radio installer, and am using that antenna as primary. The MXTA26 SWR sweep across the UHF band from a RigExpert AA-650 Zoom antenna analyzer and picture of the mounting configuration are attached. Quote Link to comment Share on other sites More sharing options...
PRadio Posted November 4, 2020 Report Share Posted November 4, 2020 Bad ground perhaps? Quote Link to comment Share on other sites More sharing options...
ljh505 Posted November 4, 2020 Author Report Share Posted November 4, 2020 Bad ground perhaps? Nah, the mount is fine. See the review of the Browning BR-173-S commercial land-mobile antenna I just posted. The Browning achieved 1.2:1 SWR at 463 MHz on the same mount. There's a couple of comments in the Midland store reviews of the antenna on Amazon that the antenna comes too short from the factory, so I'm not the only one seeing it resonate above the GMRS band. Again, the resonant point is mount-specific, but if the antenna came a bit longer from the factory, you could cut it to resonate on the GMRS band for a wider range of mounting configurations. Maybe the MXTA26 is factory cut to be resonant on the GMRS bands for center-of-roof placement on a Midland NMO mag mount? That's a pretty limited configuration, though. Many people will use a NMO antenna on a front fender or rear trunk/hatchback/tire rack mount these days, even though the NMO 3/4 inch hole mount was originally designed for center-of-roof placement. PRadio 1 Quote Link to comment Share on other sites More sharing options...
WRAK968 Posted November 4, 2020 Report Share Posted November 4, 2020 Most newer radios can run upwards of 2.0:1 without an issue so a 1.8:1 for a cheap antenna is not surprising. The factory likely cut it "in the region" of 465 and left it at that. I don't know of too many serious operators using the included antenna anyways. Quote Link to comment Share on other sites More sharing options...
WRAK968 Posted November 4, 2020 Report Share Posted November 4, 2020 Also if I recall, the midland comes with a mag mount base. Changing the base of an antenna also affects where it should be cut, that could also be why it seems so far out of range. Quote Link to comment Share on other sites More sharing options...
ljh505 Posted November 4, 2020 Author Report Share Posted November 4, 2020 The factory likely cut it "in the region" of 465 and left it at that. I don't know of too many serious operators using the included antenna anyways. The MXTA26 is not included with any radio by default, though it may be sold as part of a kit by various online vendors. I purchased the MXTA26 stand-alone from Midland directly. Its MSRP is $40 where it is competitive with similar single-band UHF co-linear "gain" antennas for the land-mobile radio market from Larsen, Laird, PCTEL, Tram-Browning, etc. So Midland is going after the "serious operators" market with this antenna. The oddity here is that the MXTA26 is marketed as "factory tuned" whereas most land-mobile UHF antennas are "field tuned" i.e. you have to cut the antenna to resonance for your given mounting configuration. I was curious how well "factory tuned" would actually work given the large variation in mounting configurations for land-mobile UHF antennas. Answer is the MXTA26 "factory tuned" antenna isn't resonant on the GMRS band for certain mount configurations. Not a big surprise, just providing the data in a mini-review to back up this fact. Also if I recall, the midland comes with a mag mount base. Changing the base of an antenna also affects where it should be cut, that could also be why it seems so far out of range. The MXTA26 is sold as a stand-alone NMO mount "factory tuned" antenna. Here's the link: https://midlandusa.com/product/micromobile-mxta26-6db-gain-whip-antenna/ You need to supply a separate NMO mount usually. It may be available in kit form i.e. radio/antenna/mount from various on-line vendors. But it was designed and marketed to compete with other single-band UHF NMO mount antennas, where you choose your NMO mount independently of the antenna. Quote Link to comment Share on other sites More sharing options...
WRAK968 Posted November 4, 2020 Report Share Posted November 4, 2020 I stand corrected LJH505, I believed this was the factory antenna included with micromobile radios (Which is a small mag mount antenna.) My apologies for the misinformation above. Quote Link to comment Share on other sites More sharing options...
H8SPVMT Posted November 7, 2020 Report Share Posted November 7, 2020 Mine burned the paint on the Jeeps hood but I have no way calculating the resonant point for mine on a NMO magnectic mount. Quote Link to comment Share on other sites More sharing options...
Kernlover Posted November 7, 2020 Report Share Posted November 7, 2020 Are GMRS antennas directional when mounted on a vehicle. In the past CB antennas when mounted on the left rear of a vehicle. The signal would primarily come out of the right front. Does a gmrs antenna work the same? I had planned on mounting this antenna on the roof of my pick up. Quote Link to comment Share on other sites More sharing options...
Kernlover Posted November 7, 2020 Report Share Posted November 7, 2020 Are GMRS antennas directional when mounted on a vehicle. In the past CB antennas when mounted on the left rear of a vehicle. The signal would primarily come out of the right front. Does a gmrs antenna work the same? I had planned on mounting this antenna on the roof of my pick up. Quote Link to comment Share on other sites More sharing options...
n4gix Posted November 7, 2020 Report Share Posted November 7, 2020 Yes the placement of the antenna will affect the "ground plane" which in this case is your vehicle, and have a major lobe as you described for a CB antenna. This is why the center of the roof is recommended for best coverage. Kernlover 1 Quote Link to comment Share on other sites More sharing options...
Kernlover Posted November 7, 2020 Report Share Posted November 7, 2020 Thank you WQWU626 Quote Link to comment Share on other sites More sharing options...
Shadow471 Posted November 27, 2020 Report Share Posted November 27, 2020 I'm getting a 1.04 on the Midland Mag mount.Centered on the roof.About a foot back from the moonroof.On Channel 19.Kia Nero, small SUV, sport mini wagon. Sent from my SM-G986U using Tapatalk SUPERG900 1 Quote Link to comment Share on other sites More sharing options...
1URFE57 Posted November 27, 2020 Report Share Posted November 27, 2020 I have the same antenna on a midland nmo mag mount the last time I check not a pep on SWR with 45w full power output maybe because its in the middle of the roof. Quote Link to comment Share on other sites More sharing options...
mbrun Posted November 27, 2020 Report Share Posted November 27, 2020 I have an excellent SWR using the MXTA-26 centered on the roof of a 2013 Ford Escape. The roof is the same size as a Ford Focus. MichaelWRHS965KE8PLM Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
H8SPVMT Posted December 1, 2020 Report Share Posted December 1, 2020 Because of the burned paint I manufactured a steel mount to hold the magnetic mount off to the side of the hood. BOLTED AND GROUNDED to the fender of the Jeep. (I'd post a picture but don't know how) I have held conversations up to 30 (-/+) miles on good days with repeaters and hand held GPX1000 out to 7 miles (me on a ridge and them inside a hotel room) within a straight line of sight. Quote Link to comment Share on other sites More sharing options...
1URFE57 Posted December 1, 2020 Report Share Posted December 1, 2020 Because of the burned paint I manufactured a steel mount to hold the magnetic mount off to the side of the hood. BOLTED AND GROUNDED to the fender of the Jeep. (I'd post a picture but don't know how) I have held conversations up to 30 (-/+) miles on good days with repeaters and hand held GPX1000 out to 7 miles (me on a ridge and them inside a hotel room) within a straight line of sight.I'm still puzzled it might be grounded that's why it burnt out your paint? About posting pictures have an account on photobucket.com upload your images and copy and paste the links. Quote Link to comment Share on other sites More sharing options...
ljh505 Posted December 1, 2020 Author Report Share Posted December 1, 2020 I have an excellent SWR using the MXTA-26 centered on the roof of a 2013 Ford Escape.Just out of curiosity, what NMO mount are you using, a mag mount from Midland, a 3rd party mag mount, a 3/4 inch traditional NMO hole mount in the roof, etc.? Quote Link to comment Share on other sites More sharing options...
Lscott Posted December 1, 2020 Report Share Posted December 1, 2020 Because of the burned paint I manufactured a steel mount to hold the magnetic mount off to the side of the hood. BOLTED AND GROUNDED to the fender of the Jeep. (I'd post a picture but don't know how) I have held conversations up to 30 (-/+) miles on good days with repeaters and hand held GPX1000 out to 7 miles (me on a ridge and them inside a hotel room) within a straight line of sight.I looked at a photo of the antenna base. Given it's a gain antenna I'll guess the first section is maybe a 5/8 wave. A 5/8 wave antenna needs a very good ground plane right at the base of the antenna. Using the mount you have, while it is "electrically" grounded through the set screws may not be sufficiently close to the antenna base, where the matching section is located, to function as a good ground plane. You can check that by using an NMO magnet mount type base located in the same position where the current one is located. Quote Link to comment Share on other sites More sharing options...
mbrun Posted December 1, 2020 Report Share Posted December 1, 2020 I am using the Midland MXTA12. Just out of curiosity, what NMO mount are you using, a mag mount from Midland, a 3rd party mag mount, a 3/4 inch traditional NMO hole mount in the roof, etc.? Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
ljh505 Posted December 1, 2020 Author Report Share Posted December 1, 2020 I looked at a photo of the antenna base. Given it's a gain antenna I'll guess the first section is maybe a 5/8 wave. A 5/8 wave antenna needs a very good ground plane right at the base of the antenna. Using the mount you have, while it is "electrically" grounded through the set screws may not be sufficiently close to the antenna base, where the matching section is located, to function as a good ground plane.You've gotten two posters confused here. The fellow with the "burnt paint", user @H8SVMT (https://forums.mygmrs.com/user/3591-h8spvmt/) had the antenna mounted on a mag mount on the painted part of his vehicle. Since discovering his paint was blemished by a RF burn, he has since moved the antenna to a separate metal bracket to avoid further marring of the paint. I'm the OP, and I have the antenna mounted on a Diamond K400 trunk lip mount per the original post and photo. I agree the K400 and its "set screw" attachment to the trunk lip could be suspect, but given that a commercial land mobile UHF antenna of similar design (a Browning BR-173-S) tunes up just fine to a 1.2:1 SWR on the same mount per this post: https://forums.mygmrs.com/topic/2212-browning-br-173-s-antenna-on-a-small-car/ the issue is with the MXTA26 antenna, not the K400 mount. The tuning plots provided in the original post and in the BR-173-S separate review post are from a RigExpert AA-650 Zoom, which is a fairly new antenna analyzer with UHF capability. Quote Link to comment Share on other sites More sharing options...
ljh505 Posted December 1, 2020 Author Report Share Posted December 1, 2020 I am using the Midland MXTA12.Ok, that confirms my suspicions. My guess is the MXTA26 is pre-tuned to work on the MXTA12 Midland mag mount with a center-of-roof placement. Once you deviate from that configuration, there's not enough whip length to cut-to-tune to other configurations. Quote Link to comment Share on other sites More sharing options...
IronArcher Posted December 7, 2020 Report Share Posted December 7, 2020 I have seen a lot of reviews where people complained that they were too short, but were able to get a proper replacement without hassle. Quote Link to comment Share on other sites More sharing options...
Lscott Posted December 7, 2020 Report Share Posted December 7, 2020 You've gotten two posters confused here. The fellow with the "burnt paint", user @H8SVMT, had the antenna mounted on a mag mount on the painted part of his vehicle. Since discovering his paint was blemished by a RF burn, he has since moved the antenna to a separate metal bracket to avoid further marring of the paint. I'm the OP, and I have the antenna mounted on a Diamond K400 trunk lip mount per the original post and photo. I agree the K400 and its "set screw" attachment to the trunk lip could be suspect, but given that a commercial land mobile UHF antenna of similar design (a Browning BR-173-S) tunes up just fine to a 1.2:1 SWR on the same mount per this post: https://forums.mygmrs.com/topic/2212-browning-br-173-s-antenna-on-a-small-car/ the issue is with the MXTA26 antenna, not the K400 mount. The tuning plots provided in the original post and in the BR-173-S separate review post are from a RigExpert AA-650 Zoom, which is a fairly new antenna analyzer with UHF capability.I may have mixed up the two . My idea concering the MXTA26 is it might be more sensitive to mounting location compared to other antennas. I noticed this when doing some testing on a Comet CA-2x4SR antenna, also a 5/8 wave gain antenna. The SWR varied depending on the type of mount and how the ground plane was laid out. I tried a couple of magnet mounts on my Jeep along with one home made mount using ground radials bent down at a 45 degree angle on a metal stand in the house. The last one seemed to work the best. In my case I also used the RigExpert analyzer, mine is the AA-1000 model, so I'm familiar with what they can do. https://cometantenna.com/wp-content/uploads/2013/09/CA-2x4SR.pdf Quote Link to comment Share on other sites More sharing options...
scorpion1200 Posted December 12, 2020 Report Share Posted December 12, 2020 I have a Midland MXTA26 Antenna and Midland MXTX12 Mag Mount i bought from Amazon.I have a Midland MXT400. I have other issues with 2 repeater channels rp16 and rp20.So i bought a SWR meter (Gam3Gear Surecom SW-102S).I have a perfect swr 1.0:1 ratio all across the board. The issue with the repeater channels is its showing (rp16) 462.575 not 467.575 same with channel rp20.All other repeater channels showing 467.xxx I'm reaching out to Midland. Quote Link to comment Share on other sites More sharing options...
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