Tidradio TD-H8 Power Test. Interesting Results.

[WSAA635]

The H8 is rated at 10 watts as a HAM radio. It's easy to unlock so you can use it on other frequencies and my power test on VHF/154.600MHz, MURS 5 Green Dot were as follows:

Low+.39 watts

Medium=2.45 watts

High= 9.35 watts

I then tested it on UHF/462.550MHz, GMRS Ch.15 and got these results:

Low=.57 watts

Medium=2.45 watts

High= 4.75 watts

So even unlocked it won't be "illegal" on GMRS even on high power. Still under the legal 5 watts.

I'll be curious to see what the Retevis RA89 does power wise as it's also rated at 10 watts.

[SpeedSpeak2Me]

OOC, which meter were you measuring with, and what was used as a test load?

[SvenMarbles]

If you bought the “GMRS version” of the radio. It’ll stay 5 watts even after unlocking.. You might have to use the “power tune tool” from the Tidradio website and increase the values…

It goes to 10 watts UHF and 12 on VHF. Trust me..

 

[WSAA635]

Here's the meter set up I'm using.

https://www.amazon.com/gp/aw/d/B08ZC7HS75?psc=1&ref=ppx_pop_mob_b_asin_title

I have the HAM version that's Bern unlocked. From what I understood all the radios are the same only the firmware changes depending on the setting(HAM, GMRS, Unlocked) so with it being unlocked it should give max power. 

As far as doing the power tune, nope, not touching anything. I already bricked an H3 trying to do a firmware update, not going to risk the H8. I'll live with it just the way it is.

[SvenMarbles]

2 hours ago, WSAA635 said:

Here's the meter set up I'm using.

https://www.amazon.com/gp/aw/d/B08ZC7HS75?psc=1&ref=ppx_pop_mob_b_asin_title

I have the HAM version that's Bern unlocked. From what I understood all the radios are the same only the firmware changes depending on the setting(HAM, GMRS, Unlocked) so with it being unlocked it should give max power. 

As far as doing the power tune, nope, not touching anything. I already bricked an H3 trying to do a firmware update, not going to risk the H8. I'll live with it just the way it is.

One thing that I did notice is that when doing those power tests with meters like that (and mine), what you have on the antenna side of the meter matters. Whether it be a dummy load, or a tuned antenna. I did a lot of work recently on my coax run and antenna setup. After doing that, my output readings increased.. It’s almost as though the radio feels like what you have going on down line of your coax is junky and it only puts out a lower percentage of power..

 

 

[WSAA635]

I'm hooked straight into the meter, no coax and out to the large heat sink/dummy load that came with the unit.

[WRXB215]

1 hour ago, WSAK691 said:

It’s almost as though the radio feels like what you have going on down line of your coax is junky and it only puts out a lower percentage of power.

Yes, some radios actually do this. I like to refer to it as "self preservation." 

[WSBP830]

will be using mine as a GMRS radio. 

Location fort Walton Beach Fl. 

born and raised near Vestaburg PA.

[WRXD592]

Aren't all MURS channels limited to 2 watts transmitter output?  Unlocked, it maybe not be "illegal" on GMRS, but even on medium power (2.45 watts) it is not legal for MURS.  And it's questionable whether they really comply with the 20khz bandwidth limitation with MURS.

These cheap radios always have power management issues.  There's no logic built in to monitor power output so they're all over the place.  I've tested three H8s right out of the box and the power output varied significantly between the three.

 

[WRXB215]

6 minutes ago, WRXD592 said:

Aren't all MURS channels limited to 2 watts transmitter output?

Yes. "No MURS transmitter shall, under any condition of modulation, transmit more than 2 watts transmitter power output."

7 minutes ago, WRXD592 said:

And it's questionable whether they really comply with the 20khz bandwidth limitation with MURS.

Some frequencies are tighter than that:

151.820 MHz (11.25 kHz)                                
151.880 MHz (11.25 kHz)                                
151.940 MHz (11.25 kHz)                                
154.570 MHz (20.00 kHz)                                
154.600 MHz (20.00 kHz)      

[Guest]

On 3/3/2024 at 8:17 PM, WSAA635 said:

 

So even unlocked it won't be "illegal" on GMRS even on high power. Still under the legal 5 watts.

 

Yes it under the 5w on gmrs but no it is still  “illegal” as gmrs radio because it can transmit out of the proper gmrs only channels. Not that I care, and not that it will matter at all,  I don’t own any gmrs radios but the statement might confuse some one that doesn’t know what they are doing.