Help Request:

[KamalaSucks]

I recently picked up a supposedly, and apparently,  new Midland MXT400VP3 package with the included bolt on NMO 3db Ghost Antenna mounted via the  MXTA23  to the stock roof rack bars of a 1999  Suburban  with the antenna just inside of the bars  (as opposed to just outside)  to allow for a bit more ground plane overlap and located towards the passenger side rear extreme.   I also have this powered directly to battery  (with inline fuse obviously).   

Initially, I returned this unit because the microphone jack would not stay engaged and kept popping out the unit, depending on the physical motion of the  cord.   I received a refund and then a few weeks later they just send me back the exact same unit for free  (Hellifino).   I  tried to inquire as to why they sent it back and they simply had disappeared off eBay.  So I took another stab at the hookup but do not seem to be hearing much activity in general and have yet to be able to get a  successful radio check.  However, I  happened to turn it on one evening (when I first installed it and before I did any programming) when a local net was have a session and it was very clear that there was excellent reception from a wide range of participants. But  I did not try to interrupt their meeting.   But otherwise, I generally do not hear very much  activity during scanning and all attempts for radio check have been unsuccessful.  

I do not have any other related radio equipment.  Other than lousy TX/RX performance, the basic functions of the radio seem ok as far as I can tell.

So my basic questions are:

a)  is my antenna mounting approach legitimate?

b) is there anyone in the Northwest Las Vegas area who might be willing to try a radio check with me?

c)  do they make a magnetic mount adapter for which I could remove just the END of the MXTA23 cable  and attach it to a magnetic mount but otherwise use the same cable  (since it has a detachable fitting which allows me to snake the cable it through a SMALL hole)  so that I can keep the current cable

d)  other suggestions to resolve the performance issue?

thks

[WRKC935]

First, I have a Suburban in that model range.  Thinking your luggage rack bar's are plastic coated.  Meaning you have no ground.  That will run your SWR high and make the signal going out and coming in SUCK.

Honestly, bite the bullet and put in a through hole mount.  Yes, it's a hole in the roof.  But it's a 99 Chevy Suburban.  If you told me it was a 2022 Jeep Grand Cherokee Summit I would say something else.  But it ain't.  It's a good vehicle but it's not new or even close.  The performance you gain will be worth the effort. 

But DROP THE HEADLINER part way to know where the stiffening ribs are at in the roof so you don't try to drill into them.  That will ruin your day. 

NMO or SO239 mounts are your choice.  But the NMO mount will offer more of a selection for antenna's.

Figure out if you want ham and GMRS or just GMRS.  Choose the antenna based on that decision.  I have mentioned elsewhere that the super gain mobile antenna's are great for their designed frequency range.  But SUCK when you are 10 Mhz away from it.  Lower gain antenna's will have a wider frequency range.  And contrary to the popular belief 3 or even 6dB of gain difference will have little effect on the real world performance of the antenna when talking on the radio.

 

[KamalaSucks]

@WRKC935

I am brand new to GMRS so hopefully using the right nomenclature.  I also 'feel' it is related to overall system TX/RX radiative performance limitations  (as opposed to an electronics problem in the unit).  Hence my questions related to moving over toward a magnetic mount as well as comments on ground plane.  I only am targeting GMRS (at this point)  and appreciate your comments on gain versus frequency, but will keep it in mind in case i want wider receive frequency/scanner capability.

 I've definitely questioned  the grounding effectiveness via the rail bar, especially as those bars also have rubber feet between the rail and roof, nonconductive coating (as you mentioned) as thus the only potential electrical PHYSICAL contact to vehicle 'ground' would really be through the threaded bolts holding the rail to the vehicle. I tried to 'rub' the coating when clamping and generally clamped it with alot of compression as initial approach, but not sure on effectiveness and again, there is still the effectiveness question of the rail/frame contact via those associated rail bolts  (as opposed to antenna mount clamp bolts).   HOWEVER, I am also under the impression that the radiative ground plane does NOT need to by physically coupled to the antenna  (nor to the vehicle).  Magnetic mounts generally have insulating scratch protection layers, do they not?   So this is a bit of a point of confusion for me.

With regard to images:   I currently have a (small) hole running into  the side and then down through the rear rail hold  (1974),  and  (1977) shows the rubber/plastic liner to the hold as well.  And the cable access is readily accessible through the  inside roof liner with minimal panel removal,  but  since the cable adapter for this antenna model has a detachable PL259 fitting at the radio end,  I did NOT  have to create a PL259 sized hole into the side  of the rail hold (1974) and then through the roof (hidden now but within and below the cavity of the hold bracket (1977). I could simply detach the PL259 and snake the smaller coupling through and reattach the readily threaded PL259.

My preference is probably for a magnetic NMO on the roof, though I have thought about those lip mounts as well for hood as I really dont like the idea of drilling holes in the roof.  But the roof location point would seem both higher and farther away from biological perspective to the drive.  Additionally,  with regard to lip mount, depending on the location,  this seems to be 'closer' in concept to my current rail mount from the perspective of ground plane overlap.

So based upon this commentary,  my questions would be?

a) recommended NMO mag antenna with detachable  PL259 at the radio end?

b) other comments to correct/continue me on appropriate solution?

thks,  I tried to be both thorough and explicit, with images, as I thought this was probably a quite common issues, even if basic.

PS:  also, is the antenna not physically grounded via the  coax anyway?

PPS: Also,  the tube for the rail cross beam slides into the rail end bracket, so even if the screws for the rail bracket made good electrical connection  between bracket and roof/vehicle, the connection to the rail from the insert design is probably not very effective either (as in tapered tube  inserted 'loosely' into another tube)

 

 

 

 

 

 

 

[Lscott]

13 hours ago, BidenSucks said:

d)  other suggestions to resolve the performance issue?

A lot of people seem to be attracted to those "Ghost" antennas due to their small size. IMHO I've never been impressed with their performance. Some may have had better luck with them.

I picked one up at a Ham swap a while back since it was cheap to test out. The results weren't that good.

If someone wants a small antenna I would just go with a simple 1/4 wave type, easy one is a magnet mount. It's only going to be about 6 to 7 inches tall anyway. These have a WIDE bandwidth so when trimmed right could be usable over the Ham 70cm band and the GMRS band too.

At the frequencies used by GMRS the ground plane required is only about 6 inches in radius around the antenna base for uniform coverage. The magnet mount achieves the connection to the ground plane through the base using capacitive coupling. You don't need a solid connection.

Antenna Scan Results (Stealth Dual Band VHF).pdf Antenna Scan Results (Stealth Dual Band UHF).pdf

[KamalaSucks]

@Lscott     The ghost is just what came with the unit.   Open to any other antennas, dont care about profile,  but they all seem to have fixed PL259 connectors (please correct me if Im wrong) which makes routing more difficult due to path size requirements.  I think Im going to try to rig up a metal plate attachment for the roof to try to test out the current antenna.  I have trouble believing there is so little apparent activity locally as Im Las Vegas,  though when the local sunday evening net was in progress, there was clearly a lot of people active and the reception was crystal clear, so Im still a bit confused as to issue.  I may try interrupting their meeting and get a radio check. Hopefully I have the proper programming config.  

[Lscott]

59 minutes ago, BidenSucks said:

@Lscott     The ghost is just what came with the unit.   Open to any other antennas, dont care about profile,  but they all seem to have fixed PL259 connectors (please correct me if Im wrong) which makes routing more difficult due to path size requirements.  I think Im going to try to rig up a metal plate attachment for the roof to try to test out the current antenna.  I have trouble believing there is so little apparent activity locally as Im Las Vegas,  though when the local sunday evening net was in progress, there was clearly a lot of people active and the reception was crystal clear, so Im still a bit confused as to issue.  I may try interrupting their meeting and get a radio check. Hopefully I have the proper programming config.  

You just might be unlucky to be in an area with low activity.

You can try scanning all the channels using narrow band. That would make the radio compatible with FRS radios. Usually the FRS radios are frequently employed by hotels and other small business since they don't require a license and they are cheap. See if you can get any activity that way.   

[KamalaSucks]

@Lscott   I just added some aluminum sheet  I had laying around to the base of an antenna via a single drilled hole and put the sheet between the mounting bracket and the large threaded fitting onto which the Antenna itself threads.  Tested it out as there were a few people chatting on a repeater channel.  Made contact, they were loud and clear, strong signal incoming, and they indicated I was ok, but a little scratchy.   So apparently I have at least that repeater channel set up properly.  Not pretty, but seems a step forward.     Suggestions on next step to improve?  Should I get an SWR meter ?  

[back4more70]

I have that same antenna on an NMO magnetic mount on my car roof.  I like it a lot.  So does my garage overhang.

[wayoverthere]

Midland sells a cable for hard mounting that has an NMO at the antenna end, and uses a smaller connector at the radio end, along with an adapter to pl259 for the radio.

https://midlandusa.com/products/micromobile-mxta24-low-profile-antenna-cable

Free is a good price for a phantom antenna. I've done a little testing with a laird phantom in the middle of my truck roof on a mag mount, results werent super, it was having trouble getting readable audio into a local repeater with 10 watts that I can generally use on a handheld and rubber duck.

[KamalaSucks]

43 minutes ago, wayoverthere said:

Midland sells a cable for hard mounting that has an NMO at the antenna end, and uses a smaller connector at the radio end, along with an adapter to pl259 for the radio.

https://midlandusa.com/products/micromobile-mxta24-low-profile-antenna-cable

Free is a good price for a phantom antenna. I've done a little testing with a laird phantom in the middle of my truck roof on a mag mount, results werent super, it was having trouble getting readable audio into a local repeater with 10 watts that I can generally use on a handheld and rubber duck.

@wayoverthere  Thanks, Ive seen this.   The midland antenna I have now is basically the same configuration as that.  The clamp/attachment approach is a bit different,  but otherwise it has the removal PL259 and a hole in some steel hardware for mounting the  NMO connector.    If I could just somehow add/convert to a mag mount, that would be preferred, but I have yet to find a stand alone magnetic mount that takes a user supplied NMO/cable.  Next best to that is to find an antenna with the removal PL259  (like you reference)  but in a mag mount config.    From what Ive seen, the mag mount and cables are generally integrated by the manufacturer.  Seems like a no brainer as a potential product offering, but what do I know.     

[KamalaSucks]

2 hours ago, back4more70 said:

I have that same antenna on an NMO magnetic mount on my car roof.  I like it a lot.  So does my garage overhang.

@back4more70 Dont suppose your cable has the removal PL259 on it?  that's what Im targeting.  Also, as I have a roof rack,  antenna height is not the limiter current as show by the image, but not concerned about that aspect either at this point in time  (can always remove the antenna itself as well)

[Lscott]

That solid sheet metal ground plane will be a HUGE wind load at highway speeds. I can just picture it ripping off the roof rack rail. It was ok for a static test but you need something else. The following link is a suggestion. If you’re using an NMO mount then you need to look for a kit like the one in the link using that mount type.
 

https://www.amazon.com/WORKMAN-WIL-KIT-W-ELEMENT-MOBILE-GROUND/dp/B01D3ITZ9C

[KamalaSucks]

17 minutes ago, Lscott said:

That solid sheet metal ground plane will be a HUGE wind load at highway speeds. I can just picture it ripping off the roof rack rail. It was ok for a static test but you need something else. The following link is a suggestion. If you’re using an NMO mount then you need to look for a kit like the one in the link using that mount type.
 

https://www.amazon.com/WORKMAN-WIL-KIT-W-ELEMENT-MOBILE-GROUND/dp/B01D3ITZ9C

@Lscott   thanks, understood, will keep that in mind. I am actually thinking of rigging up some plate inside the cargo backet (which has yet to be used) which has a wind defector on the front.   Just trying to make sure I understand primary issue and verify decent performance across the board first.  

[wayoverthere]

2 hours ago, BidenSucks said:

@wayoverthere  Thanks, Ive seen this.   The midland antenna I have now is basically the same configuration as that.  The clamp/attachment approach is a bit different,  but otherwise it has the removal PL259 and a hole in some steel hardware for mounting the  NMO connector.    If I could just somehow add/convert to a mag mount, that would be preferred, but I have yet to find a stand alone magnetic mount that takes a user supplied NMO/cable.  Next best to that is to find an antenna with the removal PL259  (like you reference)  but in a mag mount config.    From what Ive seen, the mag mount and cables are generally integrated by the manufacturer.  Seems like a no brainer as a potential product offering, but what do I know.     

Right? That would be a winner on a mag mount. Given they also do it on a pl259 to pl259 cable, I can't see why they (or anyone else) don't offer a similar setup on a mag mount.

It'd be way overkill, but I imagine it's be possible to work it into one of those triple magnet mounts like this one https://alphadistributor.net/shop/ham-equipment/mobile-antenna-mounts/magnetic-mounts/triplex-5-magnet-cb-antenna-mount/

[KamalaSucks]

On 6/29/2023 at 6:36 PM, wayoverthere said:

Right? That would be a winner on a mag mount. Given they also do it on a pl259 to pl259 cable, I can't see why they (or anyone else) don't offer a similar setup on a mag mount.

It'd be way overkill, but I imagine it's be possible to work it into one of those triple magnet mounts like this one https://alphadistributor.net/shop/ham-equipment/mobile-antenna-mounts/magnetic-mounts/triplex-5-magnet-cb-antenna-mount/

@wayoverthere  yup,  have seen this one also, raise portion suitable for the modification.   Think Ill try adding my own ground  plate to my roof cargo rack and see how it goes. will post results.  

[back4more70]

14 hours ago, BidenSucks said:

@back4more70 Dont suppose your cable has the removal PL259 on it?  that's what Im targeting.  Also, as I have a roof rack,  antenna height is not the limiter current as show by the image, but not concerned about that aspect either at this point in time  (can always remove the antenna itself as well)

No, the cable is attached to the NMO mount itself.  I got it on Amazon, https://www.amazon.com/gp/product/B07CRBV71V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[KamalaSucks]

On 6/30/2023 at 7:11 AM, back4more70 said:

No, the cable is attached to the NMO mount itself.  I got it on Amazon, https://www.amazon.com/gp/product/B07CRBV71V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

yup, understood...the search continues, but going to beef up my ground plane approach per above,  at next step..

[Lscott]

Just another idea.

 

[KamalaSucks]

Finally mounted the plate.   Baking sheet turned upside down clamped on edge in 4 locations to the aftermarket cargo basket with the ghost in the middle as shown in the image.

Was able to talk about 15 miles  simplex  with very good signal  on initial contact sitting in the driveway with only slight relative elevation.    Also was able to use repeater successfully as well.  I'm probably good for now.  Thanks for all the help.