Got My New MXT500 - Not Impressed

[H8SPVMT]

Well I can put this thread to bed and one more label (subject) ruined to try to keep up with.

 

[marcspaz]

On 2/7/2022 at 7:51 AM, H8SPVMT said:

Well I can put this thread to bed and one more label (subject) ruined to try to keep up with.

 

 

 

It gets hard sometimes. Part of the reason I took a break was because I was sick of the arguments.

 

Anyway, I sent the radio back to Midland last week for an alignment and to have the power turned up. Let's see how this goes. 

 

When I get it back, I'll retest the power output and blow the dust of the signal generator to test receive sensitivity.

[WROZ250]

On 2/5/2022 at 8:33 AM, marcspaz said:

 

I only have one problem with this video. He said it doesn't receive as well because it's a ROC. Not only that, he went on the say that every other type approved radio is better than the Midland, but did nothing to demonstrate that.

 

I'm a little confused by this guy (and others I have seen) complaining about the Midland and others being a ROC instead of a superheterodyne.  There are ROC systems that outperform some superheterodyne systems all day long and cost as much as $10,000 for amateur transceivers. Flex SDR is a great example. 

 

There are POS superheterodynes and POS ROCs.  The style of tech shouldn't be automatically discounted as junk or awesome based on design style alone. 

The thing is, you can have either type, ROC or SuperHet and either can be a poor design or superb.  

ROC isn't a lesser radio by default.  Ultimately it is the overall design that makes or breaks radio performance.  The problem, IMHO, is that we find ROC in many of the cheaper radios which suggests that perhaps the supporting design isn't very good.  Nevertheless, it would not be impossible to design a very high performing radio around a ROC core.

A poorly designed SuperHet can have horrible performance as well, so again, it's the overall design of a given radio, not necessarily the core technology in use.  There are many factors that determine how well or poorly a radio will perform.

Just an opinion...

[gman1971]

1 hour ago, WROZ250 said:

The thing is, you can have either type, ROC or SuperHet and either can be a poor design or superb.  

ROC isn't a lesser radio by default.  Ultimately it is the overall design that makes or breaks radio performance.  The problem, IMHO, is that we find ROC in many of the cheaper radios which suggests that perhaps the supporting design isn't very good.  Nevertheless, it would not be impossible to design a very high performing radio around a ROC core.

A poorly designed SuperHet can have horrible performance as well, so again, it's the overall design of a given radio, not necessarily the core technology in use.  There are many factors that determine how well or poorly a radio will perform.

Just an opinion...

You are right, actually. The EVX-5xxxx radios use both, they use a regular double conversion superhet, with a traditional 1st stage, but the 2nd stage is a direct conversion Rodinia chip. I think the AT-578 uses a similar approach as well, but not Rodinia on the 2nd stage... some POS 2nd stage that allows intermod galore...

Its certainly not impossible, it only costs circa $13,000 dollars for a new IC-7810 radio...  or around $5,000 for a new APX8000 radio... or around $1k or so for a new XPR7550e... not impossible, just be prepared to pay for it. You won't find such luck in CCRs I am afraid.

Anything designed poorly (regardless of what it is) will have horrible performance...

G.

[marcspaz]

9 minutes ago, gman1971 said:

Anything designed poorly (regardless of what it is) will have horrible performance...

G.

 

 

This^^^^

[marcspaz]

Hey folks, I am leaving for vacation in a couple of hours and don't have time for a proper test... but I wanted to let you all know that I got the radio back from Midland and I can't be happier.  With a quick bench test using low pressure alligator clip test wires for the power supply, I am now getting 48w of output power on both the 462MHz and 467MHz frequencies!  I'm sure with a proper power cable, it will be perfect.

 

Once I get home and have a chance to do some proper testing for output power and 12dB SINAD receiver sensitivity test, I'll share the results.

[DavidB]

I am testing my radio, using the antenna that comes with the MXT500,  using a DuraComm LPX-25 (13.8v 26A) power supply..  On my Surecom SW-102  on freq 462.700. I get SWR of 1.00 and 41.02W output...  But on 642.650 with an SWR of 1.96, it shows it is putting out 49.69W? See photos.  Isn't power supposed be less from the transmitter with higher SWR?  What can you guys teach me.....

[marcspaz]

1 hour ago, DavidB said:

I am testing my radio, using the antenna that comes with the MXT500,  using a DuraComm LPX-25 (13.8v 26A) power supply..  On my Surecom SW-102  on freq 462.700. I get SWR of 1.00 and 41.02W output...  But on 642.650 with an SWR of 1.96, it shows it is putting out 49.69W! See photos.  Isn't power supposed be less from the transmitter with higher SWR?  What can you guys teach me.....

 

SWR shows balance. If you have a 25 ohm load or a 100 ohm load, it's still a 2:1 SWR.  However, if you have a 100 ohm load, the current is lower, therefore the wattage is lower. If you have a 25 ohm load, the current increases, therefore the wattage increases. 

[DavidB]

1 hour ago, marcspaz said:

 

SWR shows balance. If you have a 25 ohm load or a 100 ohm load, it's still a 2:1 SWR.  However, if you have a 100 ohm load, the current is lower, therefore the wattage is lower. If you have a 25 ohm load, the current increases, therefore the wattage increases. 

The only thing I changed was the channel frequency, to get those two different readings, using that small antenna that came with the MXT500. Whatever ohms that antenna represents...   I take that this is "normal" to see, that the further the frequency gets away from the ideal tune of the antenna (higher SWR) that the power shown is not the actual power of the radio that is displayed? If so, to determine the actual power the radio is by getting as close to 1:1 as possible..  Right??

[marcspaz]

10 hours ago, DavidB said:

The only thing I changed was the channel frequency, to get those two different readings, using that small antenna that came with the MXT500. Whatever ohms that antenna represents...

 

I am really tired and hope I am typing this right.  LOL

 

There are two types of ohms readings we are dealing with when we talk about these different tests.  There is a inductive load which uses magnetic fields to move energy.  Then there is a non-inductive load, called a resistive load (aka dummy load). 

An antenna is an inductive load and the value of the load changes as the frequency changes and as the length and even diameter of the antenna changes.  Meaning the Ohms value changes as you change just about anything.

A resistive load is a fix value resistor (device that is the opposition to current flow).  It's value is extremely stable across great expanses of radio spectrum, and are typically only going to become an invalid test device (not being 49 to 51 ohms) if the material gets too hot or the physical makeup of the resistor is not designed to perform in the specific frequency range you want to test.

Even a near perfect antenna install is normally not a good test platform for true/scientific results due to so many variables that can impact the magnetic field as the energy travels from your radio, to and through your antenna.  Based on that, typically the antenna systems are not used for testing.  On occasion, however, for non-scientific purposes (general discussion) we may conduct a test involving an antenna if the antenna is the subject of the test or the "known to be inaccurate" results are "close enough" to illustrate a point.

 

10 hours ago, DavidB said:

I take that this is "normal" to see, that the further the frequency gets away from the ideal tune of the antenna (higher SWR) that the power shown is not the actual power of the radio that is displayed?

 

eh... not exactly, no.  You are correct in that the further you get away from the frequency the antenna system is tuned for, the more things change.  However, that "thing" is that the antenna system becomes unbalanced and you can start to get artificially low or high power readings.

The value you see is the actual wattage.  Watts is a mathematically calculated value, which is:

Power = Voltage * Current.

As we stated earlier, if the load (reactive or resistive) goes up (ohms increases) the current flow slows down.  Assuming a perfect world, the voltage in the radio has not changed.  There for the power goes down.  If the load (reactive or resistive) goes down (ohms decreases) the current flow goes up.  Again, the voltage in the radio is assumed to have not changed.  Therefore the power goes up.

 

 

10 hours ago, DavidB said:

 If so, to determine the actual power the radio is by getting as close to 1:1 as possible..  Right??

 

Correct.  But that is only part of the process.  The load needs to be balanced (1:1 VSWR), but the voltage also needs to be correct, at 13.8vdc measured at the radio.  Not at the power supply.

[PRadio]

17 hours ago, DavidB said:

I am testing my radio, using the antenna that comes with the MXT500,  using a DuraComm LPX-25 (13.8v 26A) power supply..  On my Surecom SW-102  on freq 462.700. I get SWR of 1.00 and 41.02W output...  But on 642.650 with an SWR of 1.96, it shows it is putting out 49.69W? See photos.  Isn't power supposed be less from the transmitter with higher SWR?  What can you guys teach me.....

The SURECOM needs to be connected to a 50 ohm dummy load to test RF Watt output. 

[DavidB]

Thanks folks!!  I so much better understand now what I am looking at, really appreciate that.  Will have a dummy load arriving any day now.... 

 

[marcspaz]

 

Okay… here are the numbers.  I will list what the Midland test numbers are and what I got for results.

 

My results –

Max Output:  47.9w @ 462.550 MHz

12 dB SINAD Sensitivity:  -122 dBm / 0.177mv

 

Midland results –

Max Output:  48.3w @ 462.550 MHz

12 dB SINAD Sensitivity:  -124 dBm / 0.141mv

 

Overall, I am very happy.  My numbers are close enough to their numbers that I am questioning the accuracy of my TEK or coupler more than their results… probably needs a calibration since it’s been almost a decade.

[Sbsyncro]

Hey all - this thread seems to have drifted around from the original post, but I'm hoping this is still the most relevant spot to post this...  A buddy of mine just got the MXT500 (I have a Wouxun KG-1000G) and we both run in a 4x4 club that uses two dedicated channels with PL tones so that when we are in busy crowded areas we can cut out all the other traffic).  Yea, I know thats not ideal, but it is what it is..    On to my question:

On the Wouxun I am able to copy the GMRS channels to a new "slot" and add the tones for the two channels so as not to change the regular "open" GMRS channels (15 & 17) on the stock radio programming.  I now have the "regular" GMRS and RPT channels, plus two additional channels called "Club1" and "Club2".   Programming the MXT500 from the keypad, I could not see a way to do this and instead had to just add the tones to the existing channels 15 and 17.

Is it possible to create two new channel slots (either via computer or FPP) so as to leave the original channels 15 and 17 open and undisturbed?

[marcspaz]

@Sbsyncro  It is not possible to enable and initially program the MXT500 "unused channels" 8 though 14 via FPP.  Those channels can only be initially enabled and setup via the programing software (Windows compatible and free from Midland).

 

Once the channel is enabled and programmed, only very basic things can be programmed via FPP, such as the tone configuration, bandwidth, power, talk-around, etc.

 

So, programming on the fly is not possible.  However, since you know in advance that you are using 15 and 17 as "Club1" and "Club2", there is no reason why you can't accomplish your goal using the programing software to set it up in advance.

[Mikeam]

4 hours ago, marcspaz said:

@Sbsyncro  It is not possible to enable and initially program the MXT500 "unused channels" 8 though 14 via FPP.  Those channels can only be initially enabled and setup via the programing software (Windows compatible and free from Midland).

 

Once the channel is enabled and programmed, only very basic things can be programmed via FPP, such as the tone configuration, bandwidth, power, talk-around, etc.

 

So, programming on the fly is not possible.  However, since you know in advance that you are using 15 and 17 as "Club1" and "Club2", there is no reason why you can't accomplish your goal using the programing software to set it up in advance.

That is what made me buy the KG1000G (just more versatile). This for me was more the repeaters on my cross state runs with multiple repeaters on one frequency but different codes.

[wayoverthere]

So, back here since this seems to be the main MXT500 thread.

Went digging for the MXT500 manual tonight related to the thread in the guest forum about scanning issues, and stumbled into the programming guide first instead. What stands out most, looking at the screenshots in the programming guide, is how similar the screens are to the software for the anytone at779/radioddity Db20G/retevis RA25 triplets...there's a couple screenshots over here:

 

[marcspaz]

@wayoverthere  I'm not surprised.  These companies seem to not put much money into the software piece.  Seems like none of them customized the windows at all, defaulting to the built-in colors and presentation from Windows, which gives them all the same look and feel.

[wayoverthere]

6 minutes ago, marcspaz said:

@wayoverthere  I'm not surprised.  These companies seem to not put much money into the software piece.  Seems like none of them customized the windows at all, defaulting to the built-in colors and presentation from Windows, which gives them all the same look and feel.

No disagreement there; some are better than others (the program for my yaesu ft4x isn't awful), but it's probably the main reason RT systems was able to carve out a place in the market.

It's mainly the window for editing the settings on a specific channel that hit me, as the naming boxes and the settings seem to pretty much mirror each other. Is this a hint that the mxt500 has a cousin on (or coming to) the market under a different brand?

Between the software and the past crossover with the dbr2500/anytone 878, an Anytone seems likely. And with 25 watt radios being a long time thing for them, there IS room in their lineup to add a 50 watt model.

[MichaelLAX]

4 hours ago, wayoverthere said:

No disagreement there; some are better than others (the program for my yaesu ft4x isn't awful), but it's probably the main reason RT systems was able to carve out a place in the market.

Has RT released software for the DB20-G/AT-779UV/Ra-25?

I would love to pick one up and test it some time! (with apologies to Edie Adams [for you old-timers ])

[Citizen]

On 1/12/2022 at 10:42 PM, MichaelLAX said:

...like my 20 watt Anytone AT-779UV a/k/a Radioddity DB20-G!

I have in my notes that the AT-779UV at high power is actually 25 watts.  Don't remember where I read that, but it lead me to specifically make a note of it.

...

[MichaelLAX]

You may be confusing it with the Anytone AT-778; a completely different radio, which is listed for 25 watts.

If I recall correctly:@OffRoaderX's YouTube review of the DB20-G, showed it at 18 watts on his meter.

[wayoverthere]

7 hours ago, MichaelLAX said:

Has RT released software for the DB20-G/AT-779UV/Ra-25?

I would love to pick one up and test it some time! (with apologies to Edie Adams [for you old-timers ])

Not that I see, so far. It'd probably be a pretty popular one.

Mentioning it as a mental note to myself, but I wonder what id get if I installed the Midland software, and tried reading from the anytone.

edit: downloaded and installed, but no luck reading from the anytone, and trying to mess with things in the .dat and .fre files just ended up with system errors and making the program unusable.  the fact that they limit what tx frequencies you can program via the software makes me think it's not all that locked down in the firmware, similar to the Wouxun 805g, but dependent on programming limitations in the software to keep it in-band.

Edited April 19, 2022 by wayoverthere

[wayoverthere]

9 hours ago, MichaelLAX said:

You may be confusing it with the Anytone AT-778; a completely different radio, which is listed for 25 watts.

If I recall correctly:@OffRoaderX's YouTube review of the DB20-G, showed it at 18 watts on his meter.

that lines up with seeing 18 from mine into a dummy load, and 22 into an antenna, both on high...i usually use medium power.

[donniefitz2]

I found that the AT-779UV puts out 18 watts UHF and it does 25 watts VHF.