MXT275 FCC Certification and Test Reports (Added MXT400)

[jas]

Hi All,

 

I got curious about my MXT275 and so went and pulled the certification and test report for the radio. 

 

Nothing unexpected found. The radio IS narrowband -12.5 kHz 11K0F3E, and low power is setting is ~5.9 watts while high power is 17.54 watts.

 

The FCC radio grant code is MMAMXT275

 

The link to all the reports and pictures are here:

 

https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=vztA7%2FjO6CQIj5FkpBy3lQ%3D%3D&fcc_id=MMAMXT275

 

The PDF of the test report is attached.

 

All the best,

 

JAS

WRKP245

 

mmamxt275.pdf

[OldRadioGuy]

Look pretty legitimate. 

Decent margins on spurious emissions.

 

You can see little amplitude modulation sidebands about 35KHz out.

Not a problem at all.  Just a curiosity.

 

Vince

[jas]

Because it is a radio of interest I decided to look at the certification and test reports for the MXT400 as well.

 

The FCC radio grant code is MMAMXT40

 

The link to the reports and tests is here:

 

https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=jULJ9rlL%2F5bYbDlwOgv0jA%3D%3D&fcc_id=MMAMXT400
 

The test report is not attached because the forum software is reporting that it is too big.  It can easily be downloaded from the link above.

 

Of interest, two things stand out. Compared to the MXT275, which exceed its wattage ratings, the MXT400 is below it's rated power. At max power it delivers 36~37 watts of power.

 

The second thing is confusing, and might have changed since the test dates which were done in 2016, The test report cites on page 6 a "GMRS Authorized Bandwidth   20.0 kHz". I have read on multiple post on this forum that the maximum allowed is 25 kHz.  It's confusing, If 25 kHz is the maximum, then for some reason this radio was only authorized for 20 Khz?

 

Best,

JAS

WRKP245

 

 

 

[BoxCar]

Because it is a radio of interest I decided to look at the certification and test reports for the MXT400 as well.

 

The FCC radio grant code is MMAMXT40

 

The link to the reports and tests is here:

 

https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=jULJ9rlL%2F5bYbDlwOgv0jA%3D%3D&fcc_id=MMAMXT400

 

The test report is not attached because the forum software is reporting that it is too big.  It can easily be downloaded from the link above.

 

Of interest, two things stand out. Compared to the MXT275, which exceed its wattage ratings, the MXT400 is below it's rated power. At max power it delivers 36~37 watts of power.

 

The second thing is confusing, and might have changed since the test dates which were done in 2016, The test report cites on page 6 a "GMRS Authorized Bandwidth   20.0 kHz". I have read on multiple post on this forum that the maximum allowed is 25 kHz.  It's confusing, If 25 kHz is the maximum, then for some reason this radio was only authorized for 20 Khz?

 

Best,

JAS

WRKP245

Bandwidth is the amount of space allocated for a channel and all the GMRS channels are spaced 25 KHz apart. The modulation or intelligence must be contained within the limits of the channel and is limited to 20 KHz to leave a guard band or blank area of 2,5 KHz on each side of the intelligence. This explains the 20K0F3 designation. Narrowband channels are 12.5 KHz wide so their modulation is 11K0F3, 11K of modulation and 1.25 KHz of guard on each side.

[jas]

Bandwidth is the amount of space allocated for a channel and all the GMRS channels are spaced 25 KHz apart. The modulation or intelligence must be contained within the limits of the channel and is limited to 20 KHz to leave a guard band or blank area of 2,5 KHz on each side of the intelligence. This explains the 20K0F3 designation. Narrowband channels are 12.5 KHz wide so their modulation is 11K0F3, 11K of modulation and 1.25 KHz of guard on each side.

Thanks! Great info.

 

Best,

 

JAS

WRKP245

[JLeikhim]

The MXT275 and MXT400 are both narrow band radios. The cert Grant for the MXF275 is at this link.

 

https://apps.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=vztA7%2FjO6CQIj5FkpBy3lQ%3D%3D&fcc_id=MMAMXT275

 

 

A proper GMRS wide band radio will have 16K0F3E or 20K0F3E emission designator, nothing smaller.

 

Sent from my SM-T350 using Tapatalk

[jas]

The MXT275 and MXT400 are both narrow band radios. The cert Grant for the MXF275 is at this link.

 

https://apps.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=vztA7%2FjO6CQIj5FkpBy3lQ%3D%3D&fcc_id=MMAMXT275

 

 

A proper GMRS wide band radio will have 16K0F3E or 20K0F3E emission designator, nothing smaller.

 

Sent from my SM-T350 using Tapatalk

 

This is true for the MXT275. The MXT400 seems to be both narrow and wide.  The designator code for the MXT400 is narrowband just like the MXT275 but, whereas the MXT275 is only authorized as a narrowband radio the MXT400 is authorized as a wideband one (20Mhz).

 

I've attached links to scanned images of the test summary Emissions and Frequencies page for both radios below. Have a look at the designator code for each radio and then look at the bandwidth authorization at the bottom of the scans.   This leads me to believe that the designator code just says that the radio is "capable" of using whichever bandwidth is the lowest in the case of a radio with multiple bandwidth capabilities, and it is not necessarily what the radio is authorized or fully capable for FCC authorization. Kind of confusing but it makes some sense if the designator code does not have the space for specifying a bandwidth "range".

 

Link to the MXT275 - both designator and authorization are narrowband:

 

 

Link to the MXT400 - designator is narroband, authorization is not...

 

 

Best,

 

JAS

WRKP245

[JLeikhim]

This is true for the MXT275. The MXT400 seems to be both narrow and wide.  The designator code for the MXT400 is narrowband just like the MXT275 but, whereas the MXT275 is only authorized as a narrowband radio the MXT400 is authorized as a wideband one (20Mhz).

 

I've attached links to scanned images of the test summary Emissions and Frequencies page for both radios below. Have a look at the designator code for each radio and then look at the bandwidth authorization at the bottom of the scans.   This leads me to believe that the designator code just says that the radio is "capable" of using whichever bandwidth is the lowest in the case of a radio with multiple bandwidth capabilities, and it is not necessarily what the radio is authorized or fully capable for FCC authorization. Kind of confusing but it makes some sense if the designator code does not have the space for specifying a bandwidth "range".

 

Link to the MXT275 - both designator and authorization are narrowband:

 

 

Link to the MXT400 - designator is narroband, authorization is not...

 

 

Best,

 

JAS

WRKP245

 

 

100% WRONG. YOU NEED TO READ THE FCC grant I posted up above which is the actual certification.

 

 

You are misreading the test report. It clearly says 10K2F3E. The GMRS authorized bandwidth is 20.0 KHz but the radio is not certified anywhere close to that emission, likely because the hardware (minimum parts count radio) won't get you to 20 KHz bandwidth. "Authorized" in the test report simply means what the rules cited will authorize, not what the radio can attain.

 

Your contention is like saying the road has an 80 MPH speed limit and then saying that an 8 horsepower Chinese Changli electric vehicle meets the speed limit because it can cruise at 25 MPH. It may be legal, but you would be dumb to buy it.

 

Look at the math for the MXT400

 

2 x modulation + 2 x Deviation

 

(2 x 3000 Hz) = (2 x 2.1 KHz) = 10.2 KHz bandwidth. The radio can deviate only +/- 2.1 KHz

 

A proper wide band radio can deviate +/- 5.0 KHz.

 

 

MXT400 FCC Grant linked at post #8 See a "generous" 10K5F3E listed for that radio.

 

 

 

https://forums.mygmrs.com/topic/2383-midland-mxt500/page-2

 

 

I have been doing this for 45 years so I can read and understand FCC equipment certifications.

[jas]

100% WRONG. YOU NEED TO READ THE FCC grant I posted up above which is the actual certification.

 

 

You are misreading the test report. It clearly says 10K2F3E. The GMRS authorized bandwidth is 20.0 KHz but the radio is not certified anywhere close to that emission, likely because the hardware (minimum parts count radio) won't get you to 20 KHz bandwidth. "Authorized" in the test report simply means what the rules cited will authorize, not what the radio can attain.

 

Your contention is like saying the road has an 80 MPH speed limit and then saying that an 8 horsepower Chinese Changli electric vehicle meets the speed limit because it can cruise at 25 MPH. It may be legal, but you would be dumb to buy it.

 

Look at the math for the MXT400

 

2 x modulation + 2 x Deviation

 

(2 x 3000 Hz) = (2 x 2.1 KHz) = 10.2 KHz bandwidth. The radio can deviate only +/- 2.1 KHz

 

A proper wide band radio can deviate +/- 5.0 KHz.

 

 

MXT400 FCC Grant linked at post #8 See a "generous" 10K5F3E listed for that radio.

 

 

 

https://forums.mygmrs.com/topic/2383-midland-mxt500/page-2

 

 

I have been doing this for 45 years so I can read and understand FCC equipment certifications.

Ok. you win. (sigh).