Midland MXT575 GMRS 2-Way Radio Install & Photos *SWR Report*

[0321_Bronco]

Got my MXT575 today, with the whip antenna, and cable. I have my license as well. I will admit I haven't read this entire thread. I have a couple of procedure/listening questions.

1. Is there a call channel, as Ch19 on a CB, that folks listen to and then switch over?
2. Have folks had good luck using FMS handhelds with the the GMRS? Midland told me it would work, with all due respect to them, they are trying to sell me a radio.
3. Due you have to tune the antenna and radio once installed? If so, does the CB device work, or do I need a different one? If I need a different one, what brand are others using?
4. For the antenna mount have folks found it works better in the front or rear....keep it clean please??

That's it for now. Thanks...Dave MERRY CHRISTMAS!!

16 tends to get a lot of traffic (like the old 19). Groups will often pick a channel and some privacy codes (note, they're not private nor encrypted, but the help your group stay rallied up.

Get an SWR meter (see the page on SWR notes in this thread). If your antenna is tuneable, you'll want to get good SWRs (something under 2.0 and much closer to 1:1).

DO NOT USE a CB SWR meter, you'll fry it. SWR meters are tuned to a frequency range. CB radio is 26-27 Mhz. GMRS is UHF, around 462 Mhz.

Find a spot that works for you. Some guys have had some really ingenious mounting locations. You'll want to play around with the coax length and how it's run through the horse and the position of the antenna (does it need a ground plane, etc.). Position won't matter nearly as much as proper mounting, mounting height, and SWRs. Love the hood mounted stuff some of the guys have thrown up on the thread. Good luck!

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[0321_Bronco]

Sure, happy to help. About your "tuning" question. It depends on the antenna. Some do, some don't. I'm not sure what kind of "device" you're referring to. If it's a power/SWR meter, then, yes, they are somewhat freq. specific and your CB one likely won't work with GMRS. You can get one from Amazon for less than $100. Speaking of which, you definitely want to check that SWR. Yes, your Midland is pretty tough, but if your SWR is too high it could cause damage to the radio not to mention reducing your range, etc.

Good advice. Any transceiver WILL be damaged by high SWRs. Range won't matter when you can't transmit.

 

[0321_Bronco]

I didn't read your entire post. I'm looking at the same radio, does the speaker in the mike work well? I did watch a video where to guys on the 50 watt radios were 26 miles apart, and other then a small amount of static, they worked very well. They were in the Grand Canyon area. One was done in the canyon about 1/2 mile. Could understand them in the video. Also I'm looking at the whip antenna. Do you know if it wokrs better then the one you installed?

Thanks, Dave

the Radio allows you to select which speaker you want to listen too. You can turn on either, or both at the same time.
As for antenna, more is always better. Length is your friend IF properly tuned.

 

[vzqhsg]

Can you have a GMRS and CB antenna mounted on your Bronco without interference?

 

[Tex]

the Radio allows you to select which speaker you want to listen too. You can turn on either, or both at the same time.
As for antenna, more is always better. Length is your friend IF properly tuned.

I thought the reason why you don't see long 1λ antennas on vehicles was due to the directivity lobes, which cause nulls in areas that become problematic when your vehicle is on uneven terrain or when the antenna starts whipping around. The additional gain you get in the main lobe is offset by having to deal with null spots and weak side lobes, so a shorter antenna with a broader directivity is preferred and more useful in a vehicle that's not always aimed at the person you're talking to. That's just what I've picked up over the years in aviation, so I might not be correct.

 

[0321_Bronco]

I thought the reason why you don't see long 1λ antennas on vehicles was due to the directivity lobes, which cause nulls in areas that become problematic when your vehicle is on uneven terrain or when the antenna starts whipping around. The additional gain you get in the main lobe is offset by having to deal with null spots and weak side lobes, so a shorter antenna with a broader directivity is preferred and more useful in a vehicle that's not always aimed at the person you're talking to. That's just what I've picked up over the years in aviation, so I might not be correct.

Antenna placement is more impactful on radiation than antenna element movement. Shorter antennas (depending on the operating frequency) do not have "broader directivity" if I understand your meaning. I don't follow the "main lobe offset/null spots." We're talking about directional radiation from generally low-powered mobile radios. The average user isn't going to see the effects of that. They will have a better experience with more power and better SWRs from a well mounted longer wire antenna.

Longer is always better, relative to frequency. If you look at mobile antennas on most VHF and UHF radios, a spring mount is always preferred. Chance are you won't 'bounce' the vehicle enough to see an appreciable difference in directional radiation. Moreover, you probably won't be able to maintain comms during such an evolution. Even now, you'll see HR mobile whips in use by EMS/State PD.

Now if we're talking higher power HF, different antenna theory comes into play. And aviation freqs are an entirely different matter. Hope that helps.

 

[Tex]

Antenna placement is more impactful on radiation than antenna element movement. Shorter antennas (depending on the operating frequency) do not have "broader directivity" if I understand your meaning. I don't follow the "main lobe offset/null spots." We're talking about directional radiation from generally low-powered mobile radios. The average user isn't going to see the effects of that. They will have a better experience with more power and better SWRs from a well mounted longer wire antenna.

Longer is always better, relative to frequency. If you look at mobile antennas on most VHF and UHF radios, a spring mount is always preferred. Chance are you won't 'bounce' the vehicle enough to see an appreciable difference in directional radiation. Moreover, you probably won't be able to maintain comms during such an evolution. Even now, you'll see HR mobile whips in use by EMS/State PD.

Now if we're talking higher power HF, different antenna theory comes into play. And aviation freqs are an entirely different matter. Hope that helps.

Ah, I think I can help visualize antenna directivity and what I mean by "broader directivity".
Beyond tuning for SWR, most antenna design focuses on tuning directivity to what you want to use it for. The pattern that an antenna produces is dependent on length and shape (I'll try to stay out of the different shapes and stick with simple whip antenna), so a 1/4λ is going to produce a different pattern from a 1/2λ or 5/8λ or 1λ. The shape is more or less a toroid (or multiples of) in all antenna. For the shorter λ antenna it's a really fat donut, but as you go longer, that toroid is flattened out more and able to reach further. Sort of analogous to the difference between a flood and spot light beam pattern.

This image below shows the directivity pattern in several views for what I assume to be a 5/8λ or longer antenna (couldn't find info, just looking for images online)

The longer of an antenna you go, the more weird stuff happens to that toroid as it's flattening out. Those little spikes are called side lobes, and aren't terribly useful because they're not very powerful and often aren't directed where you want them to go anyway. So some of that power is lost as a weak signal directed away from your target at the expense of flattening the donut to reach further. The spaces between the lobes are null spots, and if your target is wavering in and out of one of those null spots (or your antenna is wobbling around), you'll get fade in/fade out.

In a practical example, antenna solutions for watercraft often vary depending on how stable of a platform they are, even if they're using the exact same radio gear. Smaller vessels that get tossed about or sailing vessels that spend most of their time heeling need shorter antenna with a broad directivity, while larger motorized vessels can flatten that donut for a little more range because they're more stable and their targets are on the same plane that they are.

Finally, here's a graphical representation for all sorts of antenna lengths, the lobes and null spots become pretty radical over full wave:

With the graphical representation above, imagine your vehicle is flat and level and your buddy is climbing up a mountain ahead of you. A 1/4λ or 1/2λ would keep him within the donut, but he would be passing between two lobes if you had a 1λ antenna. Alternatively, you're going down a mountain, or you're off camber, or you're going down a trail that's making the antenna oscillate. Practically speaking those lobes aren't as pronounced and waves get bounced around off all sorts of things, so it's not like he'll be getting zero transmission from you if he's in a null spot...but your transmission will become weaker and he might lose you entirely if you're far enough away for it to matter.

If you're sticking close to your group or talking to spotters, the gain differences between 1/4λ and 1λ are negated as reception that close is going to be fine even with a rubber duckie...so why have a long antenna? If you're needing to stay in contact over longer distances, a 1/2λ or 1λ is only beneficial if everyone is stationary on the same plane and can be detrimental in other situations, so why have a long antenna? If you're needing to maintain contact beyond what a 1/4λ can achieve, you'll be using either a repeater or a directional antenna aimed at your target while you're both stationary, so why have a long antenna? That's what I meant by the gain you get from longer λ antenna is going to be offset by using it on moving vehicles and varied terrain.

From what I gather online, the two most favored antenna sizes for trail riding and overlanding are 1/4λ to get the best overall reception in as many situations as possible (mountains, dunes, etc) and 5/8λ if you want to sacrifice some of that broad directivity for a little more range (flatlands, highway, beaches, etc). The exception to this is using a stealth antenna in heavily wooded areas for spotters and a close/small group. One thing that is certainly universal with LOS comms is that the higher and less obstructed you can mount it, the better.

 

[Johnny Rebel]

Question: are these graphs meant to be viewed with the Bronco oriented in the pic below?

 

[0321_Bronco]

Ah, I think I can help visualize antenna directivity and what I mean by "broader directivity".
Beyond tuning for SWR, most antenna design focuses on tuning directivity to what you want to use it for. The pattern that an antenna produces is dependent on length and shape (I'll try to stay out of the different shapes and stick with simple whip antenna), so a 1/4λ is going to produce a different pattern from a 1/2λ or 5/8λ or 1λ. The shape is more or less a toroid (or multiples of) in all antenna. For the shorter λ antenna it's a really fat donut, but as you go longer, that toroid is flattened out more and able to reach further. Sort of analogous to the difference between a flood and spot light beam pattern.

This image below shows the directivity pattern in several views for what I assume to be a 5/8λ or longer antenna (couldn't find info, just looking for images online)

The longer of an antenna you go, the more weird stuff happens to that toroid as it's flattening out. Those little spikes are called side lobes, and aren't terribly useful because they're not very powerful and often aren't directed where you want them to go anyway. So some of that power is lost as a weak signal directed away from your target at the expense of flattening the donut to reach further. The spaces between the lobes are null spots, and if your target is wavering in and out of one of those null spots (or your antenna is wobbling around), you'll get fade in/fade out.

In a practical example, antenna solutions for watercraft often vary depending on how stable of a platform they are, even if they're using the exact same radio gear. Smaller vessels that get tossed about or sailing vessels that spend most of their time heeling need shorter antenna with a broad directivity, while larger motorized vessels can flatten that donut for a little more range because they're more stable and their targets are on the same plane that they are.

Finally, here's a graphical representation for all sorts of antenna lengths, the lobes and null spots become pretty radical over full wave:

With the graphical representation above, imagine your vehicle is flat and level and your buddy is climbing up a mountain ahead of you. A 1/4λ or 1/2λ would keep him within the donut, but he would be passing between two lobes if you had a 1λ antenna. Alternatively, you're going down a mountain, or you're off camber, or you're going down a trail that's making the antenna oscillate. Practically speaking those lobes aren't as pronounced and waves get bounced around off all sorts of things, so it's not like he'll be getting zero transmission from you if he's in a null spot...but your transmission will become weaker and he might lose you entirely if you're far enough away for it to matter.

If you're sticking close to your group or talking to spotters, the gain differences between 1/4λ and 1λ are negated as reception that close is going to be fine even with a rubber duckie...so why have a long antenna? If you're needing to stay in contact over longer distances, a 1/2λ or 1λ is only beneficial if everyone is stationary on the same plane and can be detrimental in other situations, so why have a long antenna? If you're needing to maintain contact beyond what a 1/4λ can achieve, you'll be using either a repeater or a directional antenna aimed at your target while you're both stationary, so why have a long antenna? That's what I meant by the gain you get from longer λ antenna is going to be offset by using it on moving vehicles and varied terrain.

From what I gather online, the two most favored antenna sizes for trail riding and overlanding are 1/4λ to get the best overall reception in as many situations as possible (mountains, dunes, etc) and 5/8λ if you want to sacrifice some of that broad directivity for a little more range (flatlands, highway, beaches, etc.). The exception to this is using a stealth antenna in heavily wooded areas for spotters and a close/small group. One thing that is certainly universal with LOS comms is that the higher and less obstructed you can mount it, the better.

I really did try to bite my tongue. This is NOT what my post is about.

I disagree with your assertion about 1/2 and 1/4 wave. 1/4 wave does NOT get the "best reception" in "as many situations as possible." And there is a collinear correlation between reception and transmission! Interesting use of cut and paste though theoretical, and most of this has little bearing on the OP. A <50W UHF GMRS build for Broncos.

Most of your assertions are incorrect. If you understand anything about antenna theory, or the math behind what you've posted, the answer to 'length' is self evident. Why are you taking about 'watercraft?' First aviation, now this? Geez, not the place or post for abstract antenna radiation. You've mixed about a dozen theories here. Please let's stay on topic.

 

[0321_Bronco]

Question: are these graphs meant to be viewed with the Bronco oriented in the pic below?

This is ridiculous! No, they cannot be oriented that way the graphics are not relevant to the mix and match theories he's posted. My OP was meant to instruct on the install. I specifically stayed away from antenna theory for this very reason.

Here's what to do. Get a good antenna (ground plane or not). Mount it properly on your vehicle. Be mindful of radio grounding. Install the rig properly. Run SWRs and adjust the antenna if you can. If you can, be mindful to use an antenna that gets you something better than 2:1. Pay attention to how you store your excess coax. Go have fun.

If you want to talk about HF comms, directional antennas, amplifiers, atmospherics, and the like, let's start a new thread (not you @johhny rebel).

 

[Johnny Rebel]

This is ridiculous! No, they cannot be oriented that way the graphics are not relevant to the mix and match theories he's posted. My OP was meant to instruct on the install. I specifically stayed away from antenna theory for this very reason.

Here's what to do. Get a good antenna (ground plane or not). Mount it properly on your vehicle. Be mindful of radio grounding. Install the rig properly. Run SWRs and adjust the antenna if you can. If you can, be mindful to use an antenna that gets you something better than 2:1. Pay attention to how you store your excess coax. Go have fun.

If you want to talk about HF comms, directional antennas, amplifiers, atmospherics, and the like, let's start a new thread (not you @johhny rebel).

Sorry! Didn't mean to contribute to the derailment of your OP. Just always wondered how to read those graphs and was trying to understand what @Tex was offering and what bearing it might have on the install.

To get back on track, your OP was VERY helpful when I installed my Yaesu FTM-400, so thanks for that! I fashioned my own mounting plate on the first install, but based on your recommendation, purchased the M2M plate for my next install. Since the FTM-400 is a dual band radio, I opted to install 2 separate antennas (one for each band) and run them through a gated duplexer (not sure that's the correct technical term) that filters signals outside of each band's frequency on the separate band inputs. I ran SWR's on each of the antennas directly and then from the common duplexed connection and got the same results (pretty sure they were <SWR 2.0). No idea if that's necessary or not, but figured if it's a mistake, I'll learn from it. Certainly open to constructive criticism on that setup.

If you'd like, when I get back home and find the info, I'll come back and post the details and photos if it doesn't further derail your thread.

Either way, really appreciate you taking the time to do such a detailed writeup of the install. I'm sure many others have found it helpful as well.

 

[Tex]

I really did try to bite my tongue. This is NOT what my post is about.

No, but it's exactly in line with what you replied to me with after I asked a simple question that seemed relevant to the thread and your previous post...

I don't follow the "main lobe offset/null spots."

I was just trying to get some clarification on why you think longer is better, but I never did.

I disagree with your assertion about 1/2 and 1/4 wave. 1/4 wave does NOT get the "best reception" in "as many situations as possible."

Goodness, my fault for mixing up reception with transmission. This is why I don't write thesis papers or make money as an editor.

Most of your assertions are incorrect. If you understand anything about antenna theory, or the math behind what you've posted, the answer to 'length' is self evident. Why are you taking about 'watercraft?' First aviation, now this? Geez, not the place or post for abstract antenna radiation. You've mixed about a dozen theories here. Please let's stay on topic.

No, I don't believe they are. What I've posted is fundamental to how radio antennas work and how they're ultimately designed, as opposed to simply making them longer. What I asked is why you believe the longest antenna you can get (relative to frequency) is preferable when used on "A <50W UHF GMRS build for Broncos", as you're literally the only person I've found that's made this assertion:

As for antenna, more is always better

And then again,

Longer is always better, relative to frequency

If you can't see the correlation between how antenna length affects Broncos with GMRS radios on a trail, boats, and airplanes in the same ways, with lobes and null spots, and you believe I've mixed and matched theories, then it's obvious I don't need my question answered. I'll just take my leave from your thread instead.

 

[0321_Bronco]

Sorry! Didn't mean to contribute to the derailment of your OP. Just always wondered how to read those graphs and was trying to understand what @Tex was offering and what bearing it might have on the install.

To get back on track, your OP was VERY helpful when I installed my Yaesu FTM-400, so thanks for that! I fashioned my own mounting plate on the first install, but based on your recommendation, purchased the M2M plate for my next install. Since the FTM-400 is a dual band radio, I opted to install 2 separate antennas (one for each band) and run them through a gated duplexer (not sure that's the correct technical term) that filters signals outside of each band's frequency on the separate band inputs. I ran SWR's on each of the antennas directly and then from the common duplexed connection and got the same results (pretty sure they were <SWR 2.0). No idea if that's necessary or not, but figured if it's a mistake, I'll learn from it. Certainly open to constructive criticism on that setup.

If you'd like, when I get back home and find the info, I'll come back and post the details and photos if it doesn't further derail your thread.

Either way, really appreciate you taking the time to do such a detailed writeup of the install. I'm sure many others have found it helpful as well.

All good brother! Love to see your install photos! That’s what its all about. Sounds like you’ve got some workable antennas with decent results. For this install and out purposes, you should be good to go!

Glad it helped. Thanks for the reply.

 

[Johnny Rebel]

All good brother! Love to see your install photos! That’s what its all about. Sounds like you’ve got some workable antennas with decent results. For this install and out purposes, you should be good to go!

Glad it helped. Thanks for the reply.

Man, that bronco in your avatar pic is sweet!


Here are a few quick photos of the install. Using a PCI Race Radios non ground plane antenna for VHF and a Comet SBB1 NMO for GMRS.

Mounted control head over driver’s visor and ran mic cable and programming cable behind glove box into the locations in the pic. Mounted mic to a Magnetic Mic base that is attached to the 8” screen bezel with 3M 2-sided tape. Overall, I’m happy with the install so far.

I’ve installed the Midlands in our 4Runner and Gen1 Raptor and love them. Great radios, but needed both VHF and GMRS in the Broncos, so decided to go with the Yaesu dual band instead of installing 2 different radios.

 

[0321_Bronco]

Man, that bronco in your avatar pic is sweet!


Here are a few quick photos of the install. Using a PCI Race Radios non ground plane antenna for VHF and a Comet SBB1 NMO for GMRS.

Mounted control head over driver’s visor and ran mic cable and programming cable behind glove box into the locations in the pic. Mounted mic to a Magnetic Mic base that is attached to the 8” screen bezel with 3M 2-sided tape. Overall, I’m happy with the install so far.

I’ve installed the Midlands in our 4Runner and Gen1 Raptor and love them. Great radios, but needed both VHF and GMRS in the Broncos, so decided to go with the Yaesu dual band instead of installing 2 different radios.

Yea, that's my '85 Bronco w/ a 4" and 37 Mickey Thompsons. I miss that truck. Back to the OP, dude! What a great install. Great way to use one antenna and a duplexer. I'm a big fan of that Comet antenna too. Very clean. Love that light switch pack too, nice touch. Your SWRs are damn near perfect. Let's talk about the Yaesu hack for that radio off line. But you weren't kidding. Thanks for sharing all that. Semper Fi!

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