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Got My New MXT500 - Not Impressed


marcspaz
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Ah, you're right, again I did not read what was right in front of me: Tx(400 - 489.995MHz)

Still, 70 cms would be of interest somewhat.

I wasn't present in the Waiting Room for the Anytone/Radioddity/Retevis Ra-25 series of radios, but they are Part 95 certified and easily "opened" whether by using a keypad sequence, or right there in the included CPS software.

So at least they started life as GMRS certified! 😉

UPDATE: I'd LOVE a db50-G! 

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I went to program in some local repeaters as a programming exercise with the MXT500 software and I noticed that the DCS tone needed to "hit" a local repeater is missing from the list provided by the Midland software!

Another Midland "feature?"

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Is it one of the standard DCS/DPL codes ? I know a lot of CCR's have extra tones that are not in Motorola and other radios. I glanced at the list and thought most were in the midland but I'll need to dig out my DPL list and verify.

 

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Just a thought. I suspect your radio is putting out close to 50w, it's just that you're measuring over the air instead of using a dummy load. Your meter isn't very accurate either as with all these consumer grade meters. I'm not knocking your equipment, but if you're not using a Bird 43 or equivalent into an accurate 50 ohm dummy load you can read anything but what the radio is really putting out. I suspect your radio is fairly close to spec.

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I'm waiting on the 575 to hit. As soon as it does I'll be ordering one and will put it on my service monitor and validate. I hate to order the 500 to do true tests as I have no need for it. The 275 is what I'm running right now and plan to upgrade just to test more or less. 

On testing I agree that real world over the air vs into a dummy load may be different. In TIA102 testing standards radios there is a tolerance for all tests on a radio. Normally this is provided by the manufacturer but TX power of +/- 10% after accounting for test cable and internal cable losses is not uncommon. Any test is going to show some uncertainty. Using calibrated test cables, calibrated test equipment is really the only way to know for sure. Many don't have access to either. In addition environmental factors could cause a reading to be different in field use. 

 

I think Mark provided a good representation of what other users would see using similar gear. 99% of the hobby uses hobby gear. While I love my Bird 43 that's kind of like a 57 Chevy in regards to technology updates also. Now Bird and Rohde & Schwarz make some really nice stuff (AKA not cheap). 

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12 hours ago, MichaelLAX said:

I'm only looking to be impressed if it can be opened to transmit on 2 meters and 70 cms, like my 20 watt Anytone AT-779UV a/k/a Radioddity DB20-G!

+1 on this. I bought a Radioddity DB20-G because it was only about $100 and could be opened up to 2 meters and 70 cm.......yet I know many people that seem to like the Midlands. Even radio savvy people, until the coiled cord breaks (Previous Midland series).

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53 minutes ago, gortex2 said:

I'm waiting on the 575 to hit. As soon as it does I'll be ordering one and will put it on my service monitor and validate. I hate to order the 500 to do true tests as I have no need for it. The 275 is what I'm running right now and plan to upgrade just to test more or less. 

On testing I agree that real world over the air vs into a dummy load may be different. In TIA102 testing standards radios there is a tolerance for all tests on a radio. Normally this is provided by the manufacturer but TX power of +/- 10% after accounting for test cable and internal cable losses is not uncommon. Any test is going to show some uncertainty. Using calibrated test cables, calibrated test equipment is really the only way to know for sure. Many don't have access to either. In addition environmental factors could cause a reading to be different in field use. 

 

I think Mark provided a good representation of what other users would see using similar gear. 99% of the hobby uses hobby gear. While I love my Bird 43 that's kind of like a 57 Chevy in regards to technology updates also. Now Bird and Rohde & Schwarz make some really nice stuff (AKA not cheap). 

One question, do we know his SWR? I would agree with you if we can confirm his antenna is properly tuned and resonating so that the high SWR circuitry isn't clamping down. I'll bet if he put any type/quality 50 ohm dummy load behind his meter the power will jump up.

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2 hours ago, tcp2525 said:

Just a thought. I suspect your radio is putting out close to 50w, it's just that you're measuring over the air instead of using a dummy load. Your meter isn't very accurate either as with all these consumer grade meters. I'm not knocking your equipment, but if you're not using a Bird 43 or equivalent into an accurate 50 ohm dummy load you can read anything but what the radio is really putting out. I suspect your radio is fairly close to spec.

 

I tested the radio using a 40 amp Astron adjustable power supply set to 13.8vdc for the power source.  For a load, I first tested with a Diamond X300 Repeater antenna and a Diamond watt meter.  When I did not get the expected results, I move to a Vectronics 50 Ohm resistive load, monitoring the output with a Tectronics oscilloscope and a Bird watt meter.  I am using just 12 feet total of LMR400 patch cables and they all test fine.

It's got a clean signal with minimal spurs.  My SWR on the live antenna was 1.1:1 and the dummy load was a perfect 1:1.  This radio is NOT putting out 50 watts.

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So using some math here 10% +/- is 5 watts. So that puts the radio at 45 watts in specification to some point. Take your cable loss and connectors out of the mix I think 40 watts is what you would get.

As reference I just finished the install of a 100 watt GTR 8000 repeater. Programming shows 100 watts. My R&S Meter shows 79 watts. Jumper in radio to back plain is .18 db. Cable from Base to Power Sensor is .75 db. That is about 1 db for quick math. 1 db from 50 db (100 Watts = 50 db) is 49 db which is 79.433 watts. So in all you still meet the 10% +/-

With the Midland 50 watts should be about 47 db. Just take away 1 db for cables and inconsistency of meters. That's 40 watts (39.811 per my PC)

So in reality it most likely meets the specs provided by the manufacturer. I think too many get worked up over a number. I think the real test is the real world use that Mark plans to use it for. I'm curious to see what he finds and how the radio performs in the world and not on a bench.  I like to see a number on my service monitor or watt meter match what a box says but it doesn't always happen. 

 

Mark keep us posted once its in the JT ! 

 

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19 minutes ago, marcspaz said:

 

I tested the radio using a 40 amp Astron adjustable power supply set to 13.8vdc for the power source.  For a load, I first tested with a Diamond X300 Repeater antenna and a Diamond watt meter.  When I did not get the expected results, I move to a Vectronics 50 Ohm resistive load, monitoring the output with a Tectronics oscilloscope and a Bird watt meter.  I am using just 12 feet total of LMR400 patch cables and they all test fine.

 

It's got a clean signal with minimal spurs.  My SWR on the live antenna was 1.1:1 and the dummy load was a perfect 1:1.  This radio is NOT putting out 50 watts.

Good enough for me. Send it back for a refund. Thanks for testing.

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Dude... Midland just completely punked out.  They said the specs are 42-50 watts.  They are trying to get out of it by saying it's close enough and my gear.

 

@gortex2  The 12 feet is the total length of the antenna transmission path.  I may have added too much information, causing some confusion with that statement.  There is only 3 feet of patch cable between the radio and the watt meter and the meter shows a perfect 50 Ohm load, so the rest of the path, after the meter should not be relevant, no?  

My loss meter is showing 0.102dB on the patch cable.  The watt meter is not reading at the end of the path, it’s the first item in the path (not including the cable).  Even if we get really picky and add the typical 0.019 dB per UHF connector, we are assuming a total of 0.204 dB of loss, not 1 dB.  That should be a total measured output power of 47.7 watts.  Would you agree?

I’m not trying to give anyone at Midland a hard time.  I am a life-long Midland customer, purchasing CB’s, FRS and GMRS handhelds and GMRS mobile radios.  I love the products.  The main reason why I am even complaining is because my MXT400 (siting right next to me) is putting out the exact same power (measured) as the MXT500, which is supposed to be more powerful.  So I hop people can understand my frustration.

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1 hour ago, tcp2525 said:

Good enough for me. Send it back for a refund. Thanks for testing.

 

I highly doubt that is going to happen.  I need a weather resistant radio for offroading with no roof and doors on my Jeep.   I have been pulling my mobiles and using cheap HT's for my trips and its getting old.

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Marc,

I took some power-output measurements and associated photos of a direct competitor of the MXT500. The configuration consists of 3-feet RG-58 between radio and power meter and 50-ohm dummy load connected directly to the meter output. The Fluke shows the voltage of the power supply feeding the radio. Both measurements represent settled voltage and power at end of 5-seconds of Tx. As you can see, power ranged from 45w-47w. i would expect Midland to meet or exceed these.

3a54c6298fa1cddfbc9b17c3522199ba.jpg
f21cab3775de1ff7a8be14e128526024.jpg


Michael
WRHS965
KE8PLM

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14 minutes ago, mbrun said:

Marc,

I took some power-output measurements and associated photos of a direct competitor of the MXT500. The configuration consists of 3-feet RG-58 between radio and power meter and 50-ohm dummy load connected directly to the meter output. The Fluke shows the voltage of the power supply feeding the radio. Both measurements represent settled voltage and power at end of 5-seconds of Tx. As you can see, power ranged from 45w-47w. i would expect Midland to meet or exceed these.

3a54c6298fa1cddfbc9b17c3522199ba.jpg
f21cab3775de1ff7a8be14e128526024.jpg


Michael
WRHS965
KE8PLM

 

Michael, that is fantastic and exactly what I would expect!  Thank you so  much for taking the time to perform this test.  It is very much appreciated and helps confirm my data. 

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50 minutes ago, marcspaz said:

 

Michael, that is fantastic and exactly what I would expect!  Thank you so  much for taking the time to perform this test.  It is very much appreciated and helps confirm my data. 

Marc,

What did the numbers look like into antenna vs dummy load? I don't have a 50w dummy load currently, but I can get some numbers similar to Michael's off my Btech for another reference point if it will help.

I know my vertex (rated for 45 watts) showed 43 at the radio with a 5/8wave whip on the other side of the meter.

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Just now, wayoverthere said:

Marc,

What did the numbers look like into antenna vs dummy load? I don't have a 50w dummy load currently, but I can get some numbers similar to Michael's off my Btech for another reference point if it will help.

I know my vertex (rated for 45 watts) showed 43 at the radio with a 5/8wave whip on the other side of the meter.

 

The numbers were almost identical.  It showed a little more power on the antenna (+ 2w), which doesn't surprise me.  As the load varies slightly, you can expect measured forward power to move a bit.

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7 minutes ago, marcspaz said:

 

The numbers were almost identical.  It showed a little more power on the antenna (+ 2w), which doesn't surprise me.  As the load varies slightly, you can expect measured forward power to move a bit.

Thanks..I know it'll vary some, just hoping for a rough idea how much to variance to expect.  Also finalizing an Amazon order so I should have a dummy load in the not too distant future.

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13 minutes ago, wqmm866 said:

I have to ask. You are using a dummy load right? If you have a antennal problem that produces high SWR most modern radios reduce power to protect the final amp.

 

Yes, I tested on a Vectronics DL650.  It's rated for 1 MHz to 650 MHz at 1,500 watts.  Also, I tested "real-world" on my Diamond X300 repeater antenna.  My analyzer shows it has a 1.1:1 SWR at 462.5 MHz and if you watch the Diamond cross needle meter in the video I shared, you will see that under a load in the 462 MHz range, the SWR needle doesn't budge.  So, the systems ALC isn't pulling power.

 

Good questions to ask, for sure.

 

EDIT:  I forgot to add, some people mentioned being interested in seeing the meter/etc. during testing, but I had already broken down everything in the office/shack and moved to my R&R desk in the basement.  Since I didn't feel like going back upstairs, setting everything up again and breaking out the camcorder, I just hooked it up to my amateur repeater antenna and power supply and shot the video using my webcam on the PC.  So the recorded test is on a live antenna and with the Diamond watt meter... but the better test with the good equipment was not recorded.

 

There was a 1 watt difference on the 462 MHz frequencies and a 2 watt difference on the 467 MHz frequencies, between the dummy load and the antenna.  I figure that is close enough to present the concerns.

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