Midland MXT 400

I am going to buy two Midland MXT 400 GMRS radios, they advertise 40w. What sort of range should I get (obviously line of sight) with a standard 3dbi antenna.

3dBd? 3dBi isn’t much better than a dipole - but the feature here is height. There are plenty of topographic software apps that will let you calculate theoretical range from an antenna with a specific power applied and a gain figure (that you have). They need your exact location, and broadly fall into two types. One overlays the topographic information with the radio data and produces a map of how far, in each direction the 40W is useable - showing the places NO amount of power will get to. In my own location 40m will get me 30+ miles south, and 6 miles north! - to the East is the sea and the distance is therefore the horizon.

The second type of software uses a location, height, power and antenna gain at both ends of the path, and calculates the path loss - you can then work out if there is enough left to work! Most programmes of this type decide for you if the path is viable or not. This kind of software is used for setting up links from specific locations normally - but it’s ok to pick important places you want to work from.

It’s all down to topography - NOT - power. You are kind of guaranteed a certain distance by brute force with 40W - I’ve personally found that with a sensitive ‘normal’ receiver the reciprocal power is around 10W - above that, people hear you but you can’t hear them, less than 10W and you can hear them and they can’t hear you. From my location here, with 40W, I’d suspect that anywhere in a circle of maybe 5-6 miles would always work. More than that, and the black spots start to appear.

It’s heavy going - but start your quest here.
http://radiomobile.pe1mew.nl/?Calculations

First, you need to determine if GMRS is legal in your country. This is doubtful, since this is a service unique to the USA at these power levels.

GMRS is not unique to the USA … there are a load of things that are unique to the USA but not GMRS… In SA we may not transmit at 40w and we also have different channels in the same frequency range …however if you have a licenced frequency that falls within the band of the radio then you may use the radio. Anyway … I have bought the radios and they are on there way… my original question still stands , what distance should I get…I am expecting to exceed 15 miles … (line of sight) is this wish full thinking.

OK… sooo… you are saying you are not allowed to transmit 40 watts, yet you are buying 40 watt radios? Also… are you legally licensed to use any of the frequencies these radios cover?

Your original question was answered by Paul… it all depends. 15 miles mobile to mobile on UHF may not be doable. If you use one as a base station with an antenna mounted high in the air may make it. The antenna, not power output, especially on UHF, is the determining factor.

Each operating geography is different. What works for one, may not work for another.

Here is the one I use: http://www.ve2dbe.com/rmonline.html I have found it to be a good general guide.

It lets me save all my predictions so I can consult with them or work with them later. The OP really needed to consult one of these models before making a purchase.

Yes I do have a UHF frequency licensed in my name for buisness… But that is immaterial at the moment… If I want to guarantee or as close as possible what would you suggest. The specific area I want to cover is reasonably flat , small hills in a few places , it is an area in South Africa called the Orange Free State. It will be mounted on a vehicle most of the time talking back to a base station or another vehicle. For hand held the normal Midlands work fine up to a Mile. The current radio I have is a Kirisan , programmed correctly … It puts out 25w … And I do get 10-15 miles talking back to the office.

Main use is for safety in the field while hunting with clients …should something go wrong that help can be summoned not fetched.

Well, there are no guarantees… best I can say is to try the modeling software as suggested.
Or hire a communications company to do an analysis and contract with them to provide equipment. In a safety situation, this may be critical.
Try your radios on test runs and hope they work. It isn’t much; but, everyone’s environment is different, so there is no sure fire guarantee on range. You could push out 100 watts and get a mile, another person in a different scenario could use 5 watts and get out 20 miles. It all depends on each person’s geography.

Ok so I tested the Radios … with 3dbi antennas … the terrain is flat but with a lot of shrub/trees between 8’-20’ from vehicle to vehicle get + - 4-5 fading at 3.5’ miles … in any direction no hassles I get 3-4 miles. THEN - when I raise one antenna to 20’ (becomes a base station) Get 10 miles no issue … at about 7 it fades then comes back at 8miles still audible and usable … then fades … Raised the vehicle antenna to 20’ (yes I know you cant drive like that) 15 miles NO ISSUE ! but fades quickly after that.

We took the radio up a grain tower, (150’) we spoke back to the “base station” at 20 miles (faint but usable) :oI’m happy with the radios. :o

Question … would VHF be better … would a 6dbi antenna on the UHF improve the situation better.

just purchased on line Midland EX37VP X-Talker 2-way Radio
any feed back, work uses Motorola

You should start your own thread on this radio, not hijack another thread with this, thanks :slight_smile:

i too just bought this radio. VERY VERY new to this! me and my hunting partners have garmin 520 radios so this type of radio in my jeep will make for a good device for me.
I have a CB in my jeep. the antenna deploys out of the rear qtr panel into a big chrome ball attached to a spring and a 14" antenna. WOULD LOVE TO USE THIS BUT I’M TOLD IT WON’T WORK. i think i need a uhf 450-470 MHz antenna???
what antennas can i use to replace this antenna? use the same hole? in a lot of brush w this jeep so the spring loaded setup is awesome!
HELP a rookie out w some simple english so i can get it running. web links to product would be cool too??? :eek:

CB radio antennas are tuned for the VHF frequencies on the CB band. The MXT400 operates on GMRS frequencies in the UHF band, so your CB antenna will not work for GMRS.

Midland has a selection of mobile antennas and mounts designed to be used with the MXT400. In addition, there are a number of antennas and mobile mounts available from third party manufactureres that will do the job.