Radio to radio variances

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GadgetguyToronto

Radio to radio variances

Post by GadgetguyToronto » Thu Jul 29, 2021 12:56 am

Hello all, you may find my experiences interesting, so I thought I share.

I bought a GD77 on Amazon about two weeks ago.

I was not impressed by the LCD left row of pixels not being visible (when looking straight on the screen) so I returned the radio for an exchange.

That first (returned) radio had two other issues:
1. The (short) antenna had a malformed base so I had to shave it off in order for it to fit into the hole as otherwise it would not go in at all
2. The charging circuit stopped at 8.2Volts (with green LED coming on), with the software inside the radio giving the same voltage (8.2 and 94%) what my voltmeter gave when measuring the actual voltage. So two ways to check the voltage - same result.

So today I got the new radio and I am comparing:
- The screen has the exact same issue - I guess I have to live with that (this is purely cosmetic)
- The antenna is also malformed (a bit less, so I can force it in): I will use an SMA to BNC adaptor so not an issue
- The charging circuit works now perfectly (when I measure the battery just after the charger turns green I get 8.39V), however the radio internal voltage display gives me 8.6V (and it gave 100% starting at 8.4V internally indicated voltage) so 0.2V more than the actual measured voltage.

Two radios: two shared issues (left pixel row not visible and malformed antenna) and two differences: on the second radio the charger hardware seems to be working well but the voltage detection software is not totally accurate (while it was on the first radio)...

I guess this is the level of consistency one can expect for a sub $100 radio?

Still: overall I am looking forward to using the amazing OpenGD77 and I am sure I will have questions as I learn it - I hope you do not mind.

Thank you!

VK3KYY
Posts: 7475
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Radio to radio variances

Post by VK3KYY » Thu Jul 29, 2021 10:20 am

GadgetguyToronto wrote:
Thu Jul 29, 2021 12:56 am
Hello all, you may find my experiences interesting, so I thought I share.

I bought a GD77 on Amazon about two weeks ago.

I was not impressed by the LCD left row of pixels not being visible (when looking straight on the screen) so I returned the radio for an exchange.

That first (returned) radio had two other issues:
1. The (short) antenna had a malformed base so I had to shave it off in order for it to fit into the hole as otherwise it would not go in at all
2. The charging circuit stopped at 8.2Volts (with green LED coming on), with the software inside the radio giving the same voltage (8.2 and 94%) what my voltmeter gave when measuring the actual voltage. So two ways to check the voltage - same result.

So today I got the new radio and I am comparing:
- The screen has the exact same issue - I guess I have to live with that (this is purely cosmetic)
- The antenna is also malformed (a bit less, so I can force it in): I will use an SMA to BNC adaptor so not an issue
- The charging circuit works now perfectly (when I measure the battery just after the charger turns green I get 8.39V), however the radio internal voltage display gives me 8.6V (and it gave 100% starting at 8.4V internally indicated voltage) so 0.2V more than the actual measured voltage.

Two radios: two shared issues (left pixel row not visible and malformed antenna) and two differences: on the second radio the charger hardware seems to be working well but the voltage detection software is not totally accurate (while it was on the first radio)...

I guess this is the level of consistency one can expect for a sub $100 radio?

Still: overall I am looking forward to using the amazing OpenGD77 and I am sure I will have questions as I learn it - I hope you do not mind.

Thank you!
The business model of Radioddity and other similar companies is to do very little, or no quality control, and simply to send replacements when people complain there is a problem.

It's probably cheaper to replace a small proportion of radios than to do some or any quality control.

The chargers were never very good. Its an analog board. Most people eventually buy a $2, 7.4V aka 2S charger module and update the charger electronics - see various recent threads.

Re: Antanna problems

I've not seen that on a GD77. It could be a batch problem

I have however see a similar problem with the Baofeng DM-1801 (GD-77 clone)



Overall for $100 for a band DMR radio, I don't think anyone is getting rich in China my making them.

kt4lh
Posts: 272
Joined: Sun Jan 12, 2020 4:27 am

Re: Radio to radio variances

Post by kt4lh » Thu Jul 29, 2021 10:57 am

Yep, get a TP5100 (you can get 2 or 5 or such for $10 off ebay) and put it in the charger base, make sure to set it to 1A. There's a thread here, plus on this page: http://members.optuszoo.com.au/jason.re ... 77mods.htm

It'll charge faster and smarter. Good thing is seemingly several radios fit this same base, so I was always able to charge my GD77 and MD380 in the same base, sold the MD380 and bought an Anytone 878 and it also fits.

GadgetguyToronto

Re: Radio to radio variances

Post by GadgetguyToronto » Thu Jul 29, 2021 6:32 pm

Thank you - already ordered a couple TP5100 boards, just takes time to get here.

I appreciate the comments!

People add various other components to the board (capacitor, coil etc.) - the board should work without those too, right?

So just be connecting the 12v to the input and the output to the charging terminal?

VK3KYY
Posts: 7475
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Radio to radio variances

Post by VK3KYY » Thu Jul 29, 2021 10:42 pm

GadgetguyToronto wrote:
Thu Jul 29, 2021 6:32 pm
Thank you - already ordered a couple TP5100 boards, just takes time to get here.

I appreciate the comments!

People add various other components to the board (capacitor, coil etc.) - the board should work without those too, right?

So just be connecting the 12v to the input and the output to the charging terminal?
Follow the instructions on http://members.optuszoo.com.au/jason.re ... 77mods.htm
Section titled "Faster charge for the GD-77. Moderate"

kt4lh
Posts: 272
Joined: Sun Jan 12, 2020 4:27 am

Re: Radio to radio variances

Post by kt4lh » Fri Jul 30, 2021 12:12 pm

Yep, what Roger said, just follow that guide, it's the absolute simplest install. Literally remove old board, put in new board, solder directly. Since I like to piddle with stuff I also added a 12v switch to turn the charger on/off so it's not idling powered (although I doubt it uses much power while not in use) and also added a small voltage display module and inserted it into the side of the charging base so I could more easily monitor my desk PSU voltage. Also figured it'd come in handy if I took the base with me somewhere and plugged into another 12V source, etc.

GadgetguyToronto

Re: Radio to radio variances

Post by GadgetguyToronto » Fri Jul 30, 2021 2:07 pm

Thank you, will do the charger mod. Already have the charger board on the way - just takes 3-4 weeks to get here

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