gd-77 HT vs md-uv380 performance

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AA3RP
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Joined: Thu Jun 17, 2021 3:22 am

gd-77 HT vs md-uv380 performance

Post by AA3RP » Tue Oct 18, 2022 11:51 pm

I have GD-77, DM-1801 (original), and RD-5r HT radio's. The GD-77 and DM-1801 are basically the same radio hardware wise, with some difference in the external key arrangement, and the RD-5r seems to be a DMR radio put into a UV-5r shell using all the same batteries and accessories.

I find no noticeable difference in performance between the GD-77 and DM-1801, and with the RD-5r it seems to not receive as well (less sensitivity in receiver?), yet due to the smaller form factor and less weight I find I carry it more often then the GD-77, or DM-1801.

I do not have a MD-UV380. I am curious about its form factor, weight, and performance in relation to the GD-77 / DM-1801, especially now that it has the 'Open' firmware running on it. At a glance it seems to be a bit smaller and lighter, and there are many reviews over the last few years praising its reciever and the audio quality.

I would like to hear from those that have both the GD-77 (DM-1801) and the MD-UV380 running the 'Open' firmware what your thoughts and impressions are between the two.

The reason I ask is that I can purchase the MD-UV380 at a very good price currently and would like some first hand reports before making my decision.

Thanks in advance
Robert P. - AA3RP

VK3KYY
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Location: Melbourne, Australia

Re: gd-77 HT vs md-uv380 performance

Post by VK3KYY » Wed Oct 19, 2022 12:25 am

I did a teardown of the UV380 / RT3S , which I posted to youtube.

The RF hardware is similar to the RD5R in that it does not have full separate PA's for VHF and UHF, and potentially not completely separate Rx pre-amp chains for both bands.

Performance is likely to be similar to the RD5R, but I don't have the level of test equipment required to make a quantitive survey of the Rx sensitivity of any radios.

I know people who have the GD77, RD5R and also UV380 and think the Rx performance is similar on all 3 radios, but performace of individual radios may vary a lot depending on the gain of the individual components in the radio, which may have a massive range of values from batch to batch during manufuring.

None of these radios uses high quality components. eg. the volume price on the RF chip is around $1 USD

ve2wkr
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Location: Silverthorne, Colorado, USA

Re: gd-77 HT vs md-uv380 performance

Post by ve2wkr » Wed Oct 19, 2022 2:15 am

Personally, I think that the UV380/RT3S is superior to the DM1801. I have both , and both the TX audio, and RX audio are much more clear and have a better audio dynamic range in the RT3S. This is comparable to the Unihertz Atom XL which also being a cell phone, has very good hardware. Also I think the screen is much better. As for RF performance, I did not notice any difference, but I will test it with my service monitor tomorrow, and post results.
73's
Luca

ve2wkr
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Re: gd-77 HT vs md-uv380 performance

Post by ve2wkr » Wed Oct 19, 2022 5:35 pm

ok, for what its worth here are the measurements for my RT3s , and my DM1801:
RT3S:
VHF 146.000Mhz , TX 6.33W rx sq open 0.2 uV ( -121dbm) loss of signal 0.134 uV (- 124.5bdm)
UHF446.000Mhz, TX 5.3W rx sq open 0.25 uV ( -119dbm) loss of signal 0.23uV ( -119.8 dbm)

DM-1801
VHF 146.000Mhz , TX 5.3W rx sq open 0.1 uV ( -127dbm) loss of signal 0.08 uV (- 128.9bdm)
UHF446.000Mhz, TX 4.90W rx sq open 0.234 uV ( -119.6dbm) loss of signal 0.22uV ( -120 dbm)

it should be noted that the tx power levels on the DM1801 have been tuned to match 5W as close as possible since I blew the VHF final on one of my DM1801s
The power levels on the RT3S cannot be easily tuned yet, so they are factory.
It looks like the DM01801 has slightly better VHF receive, but I have not measured the spurious rejection so it might be more prone to intermod.
All these measurements were made in FM with 1.5Khz deviation tones.
As a point of reference my UHF DMR repeaters receive -125dbm to -130dbm , so the HTs are in the same range.
Also for reference original baofeng UV5Rs where 10x worse , but the new tri band UV5RIII are even better then the above numbers.
73's
Luca
VE2WKR

VK3KYY
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Re: gd-77 HT vs md-uv380 performance

Post by VK3KYY » Wed Oct 19, 2022 7:57 pm

ve2wkr wrote:
Wed Oct 19, 2022 5:35 pm
ok, for what its worth here are the measurements for my RT3s , and my DM1801:
RT3S:
VHF 146.000Mhz , TX 6.33W rx sq open 0.2 uV ( -121dbm) loss of signal 0.134 uV (- 124.5bdm)
UHF446.000Mhz, TX 5.3W rx sq open 0.25 uV ( -119dbm) loss of signal 0.23uV ( -119.8 dbm)

DM-1801
VHF 146.000Mhz , TX 5.3W rx sq open 0.1 uV ( -127dbm) loss of signal 0.08 uV (- 128.9bdm)
UHF446.000Mhz, TX 4.90W rx sq open 0.234 uV ( -119.6dbm) loss of signal 0.22uV ( -120 dbm)

it should be noted that the tx power levels on the DM1801 have been tuned to match 5W as close as possible since I blew the VHF final on one of my DM1801s
The power levels on the RT3S cannot be easily tuned yet, so they are factory.
It looks like the DM01801 has slightly better VHF receive, but I have not measured the spurious rejection so it might be more prone to intermod.
All these measurements were made in FM with 1.5Khz deviation tones.
As a point of reference my UHF DMR repeaters receive -125dbm to -130dbm , so the HTs are in the same range.
Also for reference original baofeng UV5Rs where 10x worse , but the new tri band UV5RIII are even better then the above numbers.
73's
Luca
VE2WKR

Very interesting..

Thankyou

VK3KYY
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Re: gd-77 HT vs md-uv380 performance

Post by VK3KYY » Wed Oct 19, 2022 9:48 pm

BTW.

Power calibration on all UV380/RT3S radios seems quite wrong.

By default the 5W / High power setting seems to be outputting well in excess of 5W on most people's radio

I plan to make a calibration screen for the firmware, becuase its impractical to modify the CPS to handle the different calibration data tables in each type of radio, and even on the GD77, its a pain to have to use the CPS to calibrate the radio, as it involves changing values and uploading over and over again.

It would be far better if the power and freq calibration could be directly adjusted on the radio.

AA3RP
Posts: 86
Joined: Thu Jun 17, 2021 3:22 am

Re: gd-77 HT vs md-uv380 performance

Post by AA3RP » Thu Oct 20, 2022 2:57 pm

ve2wkr wrote:
Wed Oct 19, 2022 5:35 pm
ok, for what its worth here are the measurements for my RT3s , and my DM1801:
RT3S:
VHF 146.000Mhz , TX 6.33W rx sq open 0.2 uV ( -121dbm) loss of signal 0.134 uV (- 124.5bdm)
UHF446.000Mhz, TX 5.3W rx sq open 0.25 uV ( -119dbm) loss of signal 0.23uV ( -119.8 dbm)

DM-1801
VHF 146.000Mhz , TX 5.3W rx sq open 0.1 uV ( -127dbm) loss of signal 0.08 uV (- 128.9bdm)
UHF446.000Mhz, TX 4.90W rx sq open 0.234 uV ( -119.6dbm) loss of signal 0.22uV ( -120 dbm)

it should be noted that the tx power levels on the DM1801 have been tuned to match 5W as close as possible since I blew the VHF final on one of my DM1801s
The power levels on the RT3S cannot be easily tuned yet, so they are factory.
It looks like the DM01801 has slightly better VHF receive, but I have not measured the spurious rejection so it might be more prone to intermod.
All these measurements were made in FM with 1.5Khz deviation tones.
As a point of reference my UHF DMR repeaters receive -125dbm to -130dbm , so the HTs are in the same range.
Also for reference original baofeng UV5Rs where 10x worse , but the new tri band UV5RIII are even better then the above numbers.
73's
Luca
VE2WKR
Thank you for that information.

between the two which one do you find that you take with you (carry around) the most. I like the smaller size and weight of the my RD-5r and as such carry that more than the GD77/DM1801 when I am walking about with a radio.

AA3RP

AA3RP
Posts: 86
Joined: Thu Jun 17, 2021 3:22 am

Re: gd-77 HT vs md-uv380 performance

Post by AA3RP » Thu Oct 20, 2022 3:02 pm

VK3KYY wrote:
Wed Oct 19, 2022 9:48 pm
BTW.

Power calibration on all UV380/RT3S radios seems quite wrong.

By default the 5W / High power setting seems to be outputting well in excess of 5W on most people's radio

I plan to make a calibration screen for the firmware, becuase its impractical to modify the CPS to handle the different calibration data tables in each type of radio, and even on the GD77, its a pain to have to use the CPS to calibrate the radio, as it involves changing values and uploading over and over again.

It would be far better if the power and freq calibration could be directly adjusted on the radio.
Sounds like a great idea / plan. It would be great to be able to do calibration, at least for frequency and power references.

I am sure many would eagerly want and use this, I know that I would.

Thank you for all you do to make this firmware possible it is greatly appreciated.

AA3RP

UA0LMC
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Location: Vladivostok, Russia

Re: gd-77 HT vs md-uv380 performance

Post by UA0LMC » Thu Oct 27, 2022 8:06 pm

Tested DMR reception at 439MHz a couple years ago.

Baofeng RD-5r: signal loss at about -124dBm.
Unfortunately I had no DM-1801 or GD-77 then.

TYT MD-UV390: signal loss at -122dBm - and the radio is very picky about 4FSK levels, at least with it's stock firmware.
I.e., when due to hardware bug MMDVM_POG TX output was slightly clipped - it was the only radio having sudden signal losses out of five different ones tested, regardless of RF signal strength.

And just for comparison:
Baofeng DM-X is also had signal loss at about -124dBm,
Two different ADF7021-based hotspots from Aliexpress: about -70dBm at BER=5%.

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