GMRS 15 watt vs 40 watt

Is there any reason that the Midland MXT400 with 40 watts isn't coming into this conversation? I am new to GMRS and just starting my research.

Is there any reason that the Midland MXT400 with 40 watts isn't coming into this conversation? I am new to GMRS and just starting my research.

The MXT400 seems like a fine radio. @BigDaveZJ would have to answer why he went with the MXT275 instead of the MXT400, but if you're asking generically the question of mobile antennas remains the same whether you have 5 watts or 40 watts.

Do you have perhaps more pointed question or concept that is confusing that could be answered as to why you think an MXT400 should be mentioned in context of this thread? My feeling is you're seeing 40 watts verses 15 watts and that brought to mind a "Bigger is better" thought...

The MXT400 seems like a fine radio. @BigDaveZJ would have to answer why he went with the MXT275 instead of the MXT400, but if you're asking generically the question of mobile antennas remains the same whether you have 5 watts or 40 watts.

Do you have perhaps more pointed question or concept that is confusing that could be answered as to why you think an MXT400 should be mentioned in context of this thread? My feeling is you're seeing 40 watts verses 15 watts and that brought to mind a "Bigger is better" thought...

Bigger is Better is exactly what I was thinking, more watts the further the reach. I would think that a different antenna would be necessary for the higher watt radio. I am sure I will get an education from more knowledgable people than myself.

10W is more than capable of reaching the horizon for most terrain, and at these frequencies a billion watts wont make it go through the earth.. also remember this is two way communications, lets say 50W let it go 10x as far as 5w just for simplicity sake.. unless the other end has 50W your not going to establish two way communications because the other end wont make it back.

for simplex communications, high power's only benefit is you can stomp on other people easy.. if your transmitting at 50W then more than likely anyone within range will lock onto your signal if someone else is transmitting at the same time w/lesser power... if we had a bunch of mountain top repeaters like the HAM's have, then mebe 50W would be nice because you could hit them up from rather impressive distances using standard omni directional antennas.. but for most people transmitting RF, the goal is to go further with less power because if everyone uses brute force the noise floor goes through the roof.

thats a rather expensive radio IMO, I paid ~$150 more for my mobile kenwood D710 and its far, far, far more capable than the Midland.. but needs a HAM license.. in the field a 15W vs a 50W mobile GMRS radio w/same antenna setup wont see much, if any difference in range.

Is there any reason that the Midland MXT400 with 40 watts isn't coming into this conversation? I am new to GMRS and just starting my research.

10W is more than capable of reaching the horizon for most terrain, and at these frequencies a billion watts wont make it go through the earth.. also remember this is two way communications, lets say 50W let it go 10x as far as 5w just for simplicity sake.. unless the other end has 50W your not going to establish two way communications because the other end wont make it back.

@dreadlocks summed up why we didn't get the 400. And the extra cost per unit. We really only need to transmit up to 5 miles, 10 MAX, and with the terrain increasing our power isn't really going to get us to areas that we can't already cover.

Thanks for the explanations!

So I've noticed most GMRS antennas are quite short. I'm used to 3-4' CB antennas, and am not finding anything GMRS anywhere near that length. I'm sure it's got something to do with the frequency range, but with the stake pocket mount I use on my truck I find it doesn't reach up over the cab as much as I'd like. I've searched high and low for a longer antenna and coming up empty. I've got the Midland 6db gain antenna on there now, and it's approx 27" I believe. It barely peaks up over the cab, my 3' Firestik for CB mounted on the other side reaches over the cab enough to definitely get a little better signal without interfering with drive thrus and such so I'm hoping to find a similar length GMRS antenna.

Also, been playing around more with testing distances and such. My house is in a pretty poor spot for most of the testing we've done. Just south of us there's a bit of a hill that blocks LOS for anything in that direction, which is where we primarily travel. Even with that, we've still had solid comms at close to 7 miles out in suburbia. I was up quite a ways on a hill which certainly helped. Looking at adding an even higher antenna to the roof of my detached shop and put a 40w unit out there. In the event of a power outage too I can run that radio off any number of 12v batteries I have out there.

So I've noticed most GMRS antennas are quite short. I'm used to 3-4' CB antennas, and am not finding anything GMRS anywhere near that length. I'm sure it's got something to do with the frequency range, but with the stake pocket mount I use on my truck I find it doesn't reach up over the cab as much as I'd like. I've searched high and low for a longer antenna and coming up empty. I've got the Midland 6db gain antenna on there now, and it's approx 27" I believe. It barely peaks up over the cab, my 3' Firestik for CB mounted on the other side reaches over the cab enough to definitely get a little better signal without interfering with drive thrus and such so I'm hoping to find a similar length GMRS antenna.

Here is one that is just shy of 3': https://dpdproductions.com/products/gmrs-double-5-8-wave-mobile-antenna (I don't have any personal experience with them).

The antenna length has everything to do with the frequency in which it intends to radiate. A 1/4 wave CB antenna at 27mhz will be around 8.5 feet. A 1/4 wave GMRS antenna at 462mhz will be around 6 inches.

If you would prefer to not drill a 3/4 inch hole in your roof, (which there is nothing wrong with doing so, I have several) get yourself a mag mount NMO for the antenna you already have. UHF is very line-of-sight so height is critical as well as getting the antenna above the metal roof-line.

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Another bonus with the magnetic NMO on the roof; if you hit a tree branch or a parking garage, it will just knock over.

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Unfortunately magnets and aluminum don't work all that well. Kinda stuck with the stake mounts as I don't want to drill a hole in my $70k truck quite yet.

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that was a major contributor to me buying a frontrunner, was not going to drill into an expensive aluminum vehicle.

I've got a Comet CA-2x4SR on a FR antenna mount doing APRS, HAM & GMRS.. its about 40in long, last weekend I talked to someone on Pikes Peak on my way to Best Buy in Denver.. 60 miles or so.

I tell ya', that first time you drill a 3/4 inch hole in an otherwise perfectly good roof is quite a liberating experience. However, I do understand your apprehension.

If possible, see of you can find a local radio shop, i.e. the place that does the installs for the police/fire/EMS vehicles in your area and have them put an NMO on the roof for you. NMO mounts are very mechanically and electrically reliable with minimal insertion loss and a properly installed NMO will never give you any issues with leaking or anything like that. Plus, that form-factor is available on a plethora of different antennas for various bands. A few of the reasons why NMOs are widely used on service vehicles in Police, fire, EMS, Forest Serserv, DNR, etc.

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This is what my ZJ looked like at one point, no stranger to cutting stuff up, and I certainly understand the benefits of a roof mounted NMO, but it just isn't going to happen on my truck.

The ZJ, however, will certainly be getting an NMO roof mount.

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It's a bit on the expensive side but it fixes the no holes and no mag mount issue and you could run a smaller antenna as it would be higher.

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