TIDRADIO TD-H3 Compliance Test

Compliance testing to ascertain if this radio meets ITU guidelines for spurious emissions.

TIDRADIO TD-H3 Final Grade: Acceptable

The TIDRADIO TD-H3 amateur radio sample we tested was largely compliant with ITU guidelines on spurious emissions. Its second harmonic on VHF was out of compliance by less than one milliwatt which we consider to be an acceptable performance.

It is important to note that this was a single-sample test and that it is possible other samples could vary in performance.

Tests performed in Surrey, BC, Canada on July 26, 2024 by Reg Natarajan.
Discuss this radio on our forums. https://forums.advancedamateur.ca/t/tidradio-td-h3

Power Output Testing

Power output was measured using a Surecom SW-33 Plus into a dummy load. The radio was set to maximum power. The ITU guidelines for spurious emissions require measurements of "the power (W) supplied to the antenna transmission line". That requirement makes this separate power measurement necessary, as it is incorrect to measure relative to the fundamental (f0). All numbers have been rounded.

2M

146.520 Mhz

5.0 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 5.0 watts must be at least 50 dB below the power supplied to the antenna transmission line. 5.0 watts is approximately 37 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

70cm

446.000 Mhz

5.5 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 5.5 watts must be at least 50.4 dB below the power supplied to the antenna transmission line. 5.5 watts is approximately 37.4 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

1.25M

223.500 Mhz

2.5 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 2.5 watts must be at least 47 dB below the power supplied to the antenna transmission line. 2.5 watts is approximately 34 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

Spurious Emissions Testing

Spurious emissions were measured using a Tiny SA Ultra. The radio was set to maximum power and was connected to the TinySA through an attenuator. It is important to understand that the graphs below are using a decibel scale, not a linear scale. If a spurious emission spike appears to be almost as tall as the fundamental, that does not mean it is emitting almost as much power. Refer to the raw data shown.

VHF 2m Band Test Results: Acceptable

Raw Data 2m

All numbers have been rounded

Power at Antenna: 37 dBm (5 watts)

Fundamental (f0): 36 dBm (4 watts)

2nd Harmonic (2f0): -1.2 dBm (760 microwatts)

Should be less than -13 dBm (50 microwatts)

3rd Harmonic (3f0): -21.75 dBm (7microwatts)

Should be less than -13 dBm (50 microwatts)

The TIDRADIO TD-H3 sample that we tested displayed two noticeable harmonic emissions above the 2m band fundamental, one of which was out of compliance with ITU guidelines. Any spurious emissions should be at least 50 dB below the power measured at the antenna transmission line. The TD-H3's second harmonic was just 38.2 dB below, which is out of specification, but we consider this an acceptable performance given that the violation is less than one milliwatt.

UHF 70cm Band Test Results: PASS

Raw Data 70cm

All numbers have been rounded

Power at Antenna: 37.4 dBm (5.5 watts)

Fundamental (f0): 35.7 dBm (3.7 watts)

The TIDRADIO TD-H3 sample that we tested displayed no significant spurious emissions above the 70 cm band fundamental in our testing. There was one minor spike at the second harmonic that was 61 dB down from the power at the antenna which is well in compliance with ITU guidelines.

220 1.25M Band Test Results: PASS

Raw Data 1.25M

All numbers have been rounded

Power at Antenna: 47 dBm (2.5 watts)

Fundamental (f0): 31.4 dBm (1.3 watts)

2nd Harmonic (2f0): -19 dBm (13 microwatts)

Should be less than -13 dBm (50 microwatts)

The TIDRADIO TD-H3 that we tested displayed one harmonic emission above the fundamental in the 1.25m band. This emission was 66 dB below the power measured at the antenna transmission line which is well within ITU guidelines.

Comments

I purchased this radio privately from AliExpress for testing and was initially disappointed with several issues. I've since resolved these issues to my satisfaction but it may help those considering this radio to read some of my thoughts.

My radio did not arrive with the 1.25m band usable. To make it usable, I had to:
- - 1. Upgrade the firmware. Both the Unlocked and Ham firmware versions work.
    2. Put the radio in "Normal Mode" by holding PTT and *, then turn on the radio and select option 3.
    3. Use Menu 52 to allow TX on 220.
After doing this, Chirp allows programming 220 repeaters into the radio. The Chinese software and the Odmaster Android software will still not program 220 frequencies. Beyond this, if you use Chirp to do it and then try to edit your frequencies with the Chinese software or Odmaster, you will lose your 220 memories. Once you use Chirp, you're stuck with Chirp. That's an acceptable limitation to me. I generally program a radio the way I like it and then leave it alone.
It's so small that I can fit it in my man purse easily. With a telescopic antenna, it could fit into my pants pockets. This is both good and bad. It doesn't look very manly. It actually looks a bit like a toy.
USB-C charging and programming (with normal USB-C cables, not Baofeng cables and not USB-micro cables, Icom) is magic. Addictive. I think everyone hates Baofeng cables and most of us hate USB-micro cables. At least in 2024, we do. It's silly that I am excited over USB-C charging and programming, but it's even sillier that every single HT in the world doesn't already do it.
The thing has two PTT buttons, one for VFO A and the other for VFO B. If you can get used to this, it's much better than any other way of doing things. If, like me, you use a lot of different radios, it's entirely uncertain that you'll ever get used to it.
I don't hate this thing. The fact that it's acceptably clean on spurious emissions (unlike my Jianpais) and still costs under $50 with three usable transmit bands, USB charging/programming and a colour screen has me warming to it. Give me a few weeks and I may love it.
The things I wrote here were true for my H3 as of September 6, 2024. They may have changed by the time you read this.

~Reg Natarajan VA7ZEB / HJ1ZEB, September 6, 2024 (testing done on July 26, 2024)

Discuss this radio on our forums. https://forums.advancedamateur.ca/t/tidradio-td-h3