TIDRADIO TD-DP738
 Compliance Test

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

TIDRADIO TD-DP738 Final Grade: PASS

The TIDRADIO TD-DP738 amateur radio sample we tested performed exceptionally well across both of its bands.  Despite its extremely high output power, we measured no spurious emissions exceeding the levels permitted by ITU guidelines.  

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

Tests performed in Surrey, BC, Canada on August 31, 2024 by Reg Natarajan.
Discuss this radio on our forums.  https://forums.advancedamateur.ca/t/tidradio-td-dp738

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

10.1 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 10.1 watts must be at least 53 dB below the power supplied to the antenna transmission line.  10.1 watts is approximately 40 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

70cm

446.000 Mhz

9.8 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 9.8 watts must be at least 52.9 dB below the power supplied to the antenna transmission line. 9.8 watts is approximately 39.9 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: PASS

Raw Data 2m

All numbers have been rounded

Power at Antenna: 40 dBm (10.1 watts)

Fundamental (f0): 39.1 dBm (8.2 watts watts)


The TIDRADIO TD-DP738 sample that we tested displayed no significant spurious emissions above the 2 m cm band fundamental in our testing.  All spurious emissions were at least 59.5 dB down from the power at the antenna, which is fully compliant with ITU guidelines.


UHF 70cm Band Test Results: PASS

Raw Data 70cm

All numbers have been rounded

Power at Antenna: 39.9 dBm (9.8 watts)

Fundamental (f0): 38.3 dBm (6.7 watts)

The TIDRADIO TD-DP738 sample that we tested displayed no significant spurious emissions above the 70 cm band fundamental in our testing. All spurious emissions were at least 60 dB down from the power at the antenna, which is fully compliant with ITU guidelines.

Comments

This is the most powerful handheld radio I have ever tested, and that's not comforting to me.  I do not like the idea of a radio putting out 10 watts of RF right beside my eyes.  Despite that, I can't deny how clean it is.  There was nothing in the way of spurs to be found.

Many thanks to Mike VE7YEG for the use of his radio for testing. 

~Reg Natarajan VA7ZEB / HJ1ZEB, August 31, 2024


Discuss this radio on our forums.  https://forums.advancedamateur.ca/t/tidradio-td-dp738