Update 10th Feb

VK3KYY
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Update 10th Feb

Post by VK3KYY » Mon Feb 10, 2020 1:30 am

I didn't realise yesterday, when I released a new version, that the new feature from EA3IHI , to add a new channel using the parameters from the VFO, was ready to be included in the master version.

So I'm released a new version which has this feature, and also re-instates a modified version of the 5W++ power level.

https://github.com/rogerclarkmelbourne/ ... latest.sgl

The 5W++ power level can now be accessed by setting the power to 5W, and then pressing and holding Function + Right arrow.


The VFO -> New Chan functionality is accessed via the Orange button, and makes a new channel using the current VFO values.
The new channel is called "New Channel xxxx" where xxxx is the internal slot number in the codeplug channel data.
After creating the new channel the radio is switched to Channel mode and onto the All Channels zone, because this new channel is not added to a Zone, hence its only accessible via the All Channels zone.


BTW.
I did some research into the PA FET's in the GD-77, and it is supposed to be using this FET for both the UHF and VHF PA's

https://www.nxp.com/docs/en/data-sheet/AFT05MS004N.pdf

Interestingly this device is rated at 6W on VHF but only between 4.1 and 4.9W on UHF depending on various factors.

Obviously, its not just the rating of the FET its self that have to be taken into consideration, as the heat dissipation is also a major factor.
But on DMR, the heat dissipation is going to only be 50% of the heat dissipation of FM.

I think the "5W" quoted power of this radio is really just for marketing purposes. Technically its probably a 6W radio on VHF and a 4W radio on UHF, but that would not look good in the marketing blurb.

I'm also going to do some tests to look at the power output of the radio versus the battery voltage, because I'm sure that the output will drop considerably as the battery goes flat.
Ideally the power output could be corrected for batter voltage, but there isn't an easy way to do this, as I'm sure everyone's radio behaves differently.

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kd2lh
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Re: Update 10th Feb

Post by kd2lh » Mon Feb 10, 2020 2:32 am

If the thermal dissipation is adequate, the MTTF is in the millions of hours at the power (voltage and current) levels we're using even fully under power.

Then the question will be, what is the impact of the heat on adjacent components.

Still have not heard anything back from Radioddity or their Chinese lab on continuous usage.

As you've mentioned, the TDMA characteristics should reduce thermal dissipation requirements as well.

Perhaps it's time to increase power in my testing. Has anyone been testing OpenGD77 as a hotspot for an extended period of time at full or midrange power settings?

I have an IR thermometer to help evaluate heat dissipation.

It's a 90 cent part in the USA. A fair amount of the radio's budget, but likely less in quantity.

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m1dyp
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Re: Update 10th Feb

Post by m1dyp » Mon Feb 10, 2020 2:54 am

thank you all
73 de Ken :D

VK3KYY
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Re: Update 10th Feb

Post by VK3KYY » Mon Feb 10, 2020 3:12 am

@kd2lh

The FET's have no dedicated heat sink, they just rely on the copper in the PCB to conduct the heat into the chassis of the radio.


I doubt you will hear anything from Radioddity. They don't actually manufacture the radio. Its just a re-branded TYT MD-760 with updated firmware.
The MD-760 is still available direct from TYT ( https://www.alibaba.com/product-detail/ ... 13029.html ) but its actually more expensive than the GD-77 and the firmware in the MD-760 is years behind the Radioddity firmware in terms of bug fixes and also uses the v2.0 codeplug layout.

UW5ELK
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Re: Update 10th Feb

Post by UW5ELK » Mon Feb 10, 2020 4:33 am

Hello, on TYT MD-760 OpenGD77 is not suitable?

VK3KYY
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Re: Update 10th Feb

Post by VK3KYY » Mon Feb 10, 2020 5:20 am

UW5ELK wrote:
Mon Feb 10, 2020 4:33 am
Hello, on TYT MD-760 OpenGD77 is not suitable?
I've not actually tested the OpenGD77 on a MD-760, but if you open the GD77 and look at the internal model numbers it indicates its a MD-760

Hence if the GD-77 is a rebranded MD-760 the OpenGD77 firmware will run on it.

BTW. The original codeplug in the old GD-77 from 2 or 3 years ago was the MD-760 codepug and its a different format.
So if you have a MD-760 you would need to load a GD-77 codeplug into it, so that it would work with the OpenGD77 firmware

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f6fzo
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Re: Update 10th Feb

Post by f6fzo » Mon Feb 10, 2020 6:57 am

Bonjour
et merci pour tout ! ;)
F6FZO Serge 43 Nord

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Re: Update 10th Feb

Post by EB3AM » Mon Feb 10, 2020 12:49 pm

kd2lh wrote:
Mon Feb 10, 2020 2:32 am

Perhaps it's time to increase power in my testing. Has anyone been testing OpenGD77 as a hotspot for an extended period of time at full or midrange power settings?

Hello,
I have been using the GD77 on Hotspot for two days now permanently connected to the TG91 of BM. Broadcasting with 4W. He did not notice an overheating of the equipment. The TX is almost always on.
Screenshot_2020-02-10 EB3DVA - Veu Digital Panell de Control(2).png
Screenshot_2020-02-10 EB3DVA - Veu Digital Panell de Control(2).png (23.52 KiB) Viewed 413 times
Last edited by EB3AM on Mon Feb 10, 2020 12:51 pm, edited 1 time in total.

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kd2lh
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Re: Update 10th Feb

Post by kd2lh » Mon Feb 10, 2020 12:51 pm

VK3KYY wrote:
Mon Feb 10, 2020 3:12 am
@kd2lh

The FET's have no dedicated heat sink, they just rely on the copper in the PCB to conduct the heat into the chassis of the radio.


I doubt you will hear anything from Radioddity. They don't actually manufacture the radio. Its just a re-branded TYT MD-760 with updated firmware.
The MD-760 is still available direct from TYT ( https://www.alibaba.com/product-detail/ ... 13029.html ) but its actually more expensive than the GD-77 and the firmware in the MD-760 is years behind the Radioddity firmware in terms of bug fixes and also uses the v2.0 codeplug layout.
Hi Roger, Yes - thanks for specifics of the source of the radio. I knew TYT made it, but not the original design. Same thing with the GD-73 (small form factor). and others from Radioddity.

I did contact their customer service, and they did contact TYT asking about duty cycle. So far, of course, no response.

I've had the 2/10 firmware running the hotspot overnight without problems. It's reporting "FW OpenGD77:v0.1.0" to PiStar.

When new releases of firmware are posted, it would help if we knew which version number the version reported on the BBS posting. This is likely to increment more regularly now, and as things transition to wider usage it will help eliminate any confusion about what' current and how far back the radio might be.

Thanks again, Marc

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Re: Update 10th Feb

Post by F6GVE » Tue Feb 11, 2020 6:25 pm

You know that I frequently tell about the bugs that I have when listenning to DMR.
These bugs are still here but something is better than before:
With the OpenGD77 firmware I experimented some extra troubles when listening to commercial DMR repeaters (maybe some of them could be Tier3?) though I have not particular bug with the official firmware.
With this release of the firmware (may be the one before too) the RX of the commercial repeaters seems to be much more better. I can listen to the commercial conversations without the blackouts that I used to have.

Luc

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