Midland output

[Delivers1234]

Mxt 115 on a magnet mount.

Is this all I get for output?

It’s on high power.

 

[mmckenna]

It's a 15 watt radio, showing 7.35 watts. I'd want to test it by transmitting into a 50Ω dummy load to be sure. While your SWR is low, there's things that can throw off the reading by testing into the antenna.

 

[Hans13]

Here is a thread and post where he was not getting full wattage and his MXT115 was defective. Also read his post right after where he gives a YouTube video link.

Midland MicroMobile MXT100 & 115

 

[Delivers1234]

So the magnet mount does not fully touch the roof. It is on a ridge so two slices don’t touch the roof.

Could this be it?

 

[mmckenna]

So the magnet mount does not fully touch the roof. It is on a ridge so two slices don’t touch the roof.

Could this be it?

That would likely throw the SWR off.
Your SWR showing a perfect 1.00:1 is suspect. Pretty rare to get that. Might mean something else is going on. Really, the only true way to check a transmitter output power is to run it into a 50Ω dummy load. Anything else can toss off the readings.

 

[Hans13]

There are plenty of 50 ohm dummy loads on Amazon in the $20~$30 range. Cheap to find out.

 

[mmckenna]

Question:
Where do you have the meter connected? It should be connected as close to the back of the radio as you can. You'll need a jumper cable, so figure in the loss of that, plus any connector/adapters.

Also, try removing that 90º UHF connector you are using on the back of the radio. I've had issues with those in the past.

 

[Hans13]

Wait... What? I am missing where there is a 90. Is it a photo or am I missing some text? (I am either very tired tonight or blind.) lol

But yeah, 90s often make big issues at some point. One of the few radios I ever smoked was from using a 90 degree adapter. Definitely drop that variable out of the test mixture.

 

[mmckenna]

Wait... What? I am missing where there is a 90. Is it a photo or am I missing some text? (I am either very tired tonight or blind.) lol

Cable radius tolerance

So say I’m okay, I’m okay, that. I bend the coax cable like I did. It’s rounded from the radio then again to go down the center console. This is the only set up I could do. Also why is the file size for images reduced? Delivers1234

forums.radioreference.com

 

[Hans13]

Cable radius tolerance

So say I’m okay, I’m okay, that. I bend the coax cable like I did. It’s rounded from the radio then again to go down the center console. This is the only set up I could do. Also why is the file size for images reduced? Delivers1234

forums.radioreference.com

Ah, that makes more sense!

Thanks for squaring me away.

 

[nokones]

If you're going to use a cheap Dummy Load from an Amazon, you better check the resistance first to make sure it is a true 50 ohms load. Than check the RF power out and then check the dummy load resistance again to make it is still a 50 ohm load. Even 1-2 ohms off will affect an accurate reading. If I recall, 1 ohm may equate to 2 watts being inaccurate at that low of RF output power level.

And I have seen a loss of 5 dB with some cheap elbows. Cheap is not cheap, it is an hindrance and a waste of money and time.

 

[Delivers1234]

I retested to 9.60 with swr of 1.

The other day I closed the coax on a rubber knob on the back hatch door.

Haven’t tried a dummy load yet.

I think I need to try a meter to see if the coax is broken.

 

[KF0NYL]

Definitely check with a short jumper coax and a dummy load. The advice to check the dummy load is good.

Midland has had issues with radios putting out lower power than they should. I had a MXT500 two years ago that would only put out 35 watts on high into a dummy load. If that is the case then contact Midland to get it repaired.

I will not use any 90 degree adapters after having a couple go bad on me. And they weren't the cheap ones from Amazon either.

 

[mmckenna]

I retested to 9.60 with swr of 1.

Variations can indicate a couple of possibilities:

Battery voltage. Vehicle running on not.

The 12 volt system voltage will vary. With newer vehicles that have battery management systems, the vehicle will turn the alternator on/off/adjust voltage depending on needs. With the engine off, the battery voltage will be lower than when the alternator is puttin' out.
Variation in the supply voltage will directly impact the power output of the radio.

The other day I closed the coax on a rubber knob on the back hatch door.

May or may not be a problem.
If the coax is visibly pinched/damaged that could absolutely throw things off. If it's not a visible spot of damage, it may not be an issue.

Haven’t tried a dummy load yet.

I think I need to try a meter to see if the coax is broken.

That would be a good test.

 

[Delivers1234]

Survey says. I used a dummy load. Swr was the same. About 9-10 watts. 3.5 on low.

Also what gauge should I use from the car battery to this distributor? It will power gmrs, cb and ham.

And an in-line fuse 60 amp?

 

[mmckenna]

Survey says. I used a dummy load. Swr was the same. About 9-10 watts. 3.5 on low.

Did you remove the 90º adapter before testing?

Also what gauge should I use from the car battery to this distributor? It will power gmrs, cb and ham.

And an in-line fuse 60 amp?

For those 3 radios, a 20 amp circuit would be plenty. Maybe add a bit more just in case you ever expand, and design for 30 amps.
That would mean 10 gauge or larger conductor to the battery from that fuse block. Use a 30 amp fuse or circuit breaker.

If you already have the 60 amp breaker and want to use that, then you'd need to run a wire capable of at least 60 amps to be safe. That would be 6 gauge.

 

[Delivers1234]

Yes. No 90. I guess that’s all
Midland has for power.

10 gauge it is.

 

[Hans13]

Yes. No 90. I guess that’s all
Midland has for power.

10 gauge it is.

You might have missed my previous post but there is a thread here about Midlands and defective radios with reduced power all the way back to 2017. If your Midland is not producing near the amount of transmit power indicated in the specifications, I would contact Midland about a replacement (assuming it is a new radio).

Midland MicroMobile MXT100 & 115

 

[mmckenna]

Yes. No 90. I guess that’s all
Midland has for power.

I'd follow up with what @Hans13 is saying.

But a couple of things to consider:
The SWR meter you are using is not a calibrated piece of equipment. I'd give it 10% ± on the accuracy.
I'd figure in a bit of loss for the coax jumper/connectors.
I'd make 100% sure that the radio is getting a nice, clean 13.8 volts. Any less and the transmitter power output will be below spec.
The advertisements for that radio say "15 watts", which it should be able to do straight out of the back testing into a calibrated meter using jumpers where the loss has been figured in.

However, for reference, I pulled up the service manual for a Kenwood NX-800 30 watt UHF radio. In the alignment section, it gives the steps to set the transmitter for 30 watts output ±3.0watts. So even the commercial radios often don't put out the exact wattage on the nose. That's not unusual, and totally OK. On that radio, anything from 28 to 33 watts is considered good. But that's using a calibrated watt meter into a accurate 50Ω dummy load and figuring in the jumper losses.

I get the concern, though. You paid for a 15 watt radio and you should get something close to 15 watts. Just give it a bit of slack for meter accuracy and everything else. If it's a big concern, contact Midland and see if they'll swap radios with you.

The reality is that there will be very little range difference between a radio putting out 10 watts and a radio putting out 15 watts. That minor difference is easily made up by using an antenna with a bit of gain.

 

[mmckenna]

I looked up the website for your SWR meter.

SW-102 125-525MHz connector V.S.W.R. POWER METER | SURECOM

SW-102-UV Digital VHF/UHF Power & SWR Meter & Frequency counter V.S.W.R. meter IntroductionVSWR. Forward and reflected power direct digital readout, without any calibration.Maximum measurable power range up to 120W.low insertion loss (0.3 decibels or less) structure allows it to be permanently...

www.surecom.com.hk

If you look down near the bottom, it suggests there is a way to get into the menu of the device and adjust the calibration.
I'm NOT saying you should do that.
Only saying that even they give the option for the end user to do some sort of calibration. But you'd need to have the equipment to do that. I wouldn't mess with it. Just pointing out that it's an option.

So, could be the radio is out of whack.
Could be the meter is out of whack.
Could be that it's a combination of both.

If the radio works and you can communicate the way you want, then I might be tempted to call it good.