Radioddity Radioddity GD-77

[bjornepappa]

A quick update:
I got the tracking number, and it seems that something is sent from China. The destination country (Norway) is correct. So far, so good. Time will show what the package contains...
I'll keep you updated.

Update: The package has arrived! The only sad thing is that the package was to someone else than me.
I opened a request to ebay, and the case was solved in about two hours.

Sent fra min SM-G930F via Tapatalk

 

[Marco192]

Right item, wrong name? Or was the item also something other then GD-77?

I am expecting the same thing very soon

 

[bjornepappa]

What the package contained is still a mystery, since it was sent to (and collected by) someone else. The only correct was the destination country. I sent a mail to the seller, he was supposed to "check with mail office", never heard from him ever after.

Sent fra min SM-G930F via Tapatalk

 

[IW2BSF]

but is possible in the memories change the numeric frequency in alphanumerics name or not ?


RUMORS say that the collegue "TY" have to me a GF-77 Tools (like the md-230 tools) you have info?


In this moment NOT possible to HW limited put inside the all WW date base of ham radio like the

MD-380 or MD-2017 ?

 

[Forts]

Trying to understand what you are asking here... Yes, you can assign an alpha numeric name to any frequency, and yes the memory in the radio is limited and currently will not hold the database like the TYT radios will. I've heard no talk at all of any version of Ty's Toolz being ported over to this radio.

 

[IW2BSF]

ok no TY Tools on this radio....


i see this radio buy in China with the label "TYT" (the producer ! ) !!!

i coriuos to say how much vend TYT this radio.... 73

 

[Forts]

I have no idea what any of that means I'm afraid....

 

[jonwienke]

IW2BSF needs to find a better translation tool. Whatever he is using is not outputting coherent English.

 

[Forts]

I think he's saying there is a TYT branded version of the GD-77 available in China. I saw in one of the Radioddity Facebook groups a few weeks back that yes, TYT has stuck their name on these as well, however I don't think they had anything to do with the design or production of it. They've just licensed it like anything else...

 

[jje64]

There were some photos and messages floating around showing the GD-77 had "MD-780" stamped on the circuit board. Those messages were posted before TYT announced their MD-780 model.

 

[Forts]

Hmm, might have to pop mine open and have a look! I swear all of these radios seem to come from the same place sometimes...

 

[jje64]

The same messages had pointed at FCC documentation for MD-2017 approval and that documentation also had MD-780 listed as a model number. It lead one to believe that the MD-2017 and GD-77/MD-780 were the same (essential) board from an FCC standpoint for approval.

I too believe ALL of these radios are from the same core factory. As someone who works the communications/manufacturing industry, I can say LOTS of things "happen" in off-shore factories

 

[n1das]

Hytera calls this TDMA Direct Mode. Hytera PD98x radios have this feature. I have tested TDMA Direct Mode using 4 Hytera PD982 radios and I can confirm it works.

Radio A --> Radio B using time slot 1.
Radio C --> Radio D using time slot 2.

All 4 PD982 radios were on 446.075 MHz simplex with CC1 and TG99.
446.075 CC1 TG99 is the DMR-MARC simplex channel.

Key up radio A and radio C together and separate transmissions are heard on radios B and D respectively. While transmitting with radios A and C simultaneously, if I talk into radio A, I hear myself only out of radio B. If I talk into radio C, I hear myself only out of radio D. Note this is while radios A and C are both transmitting at the same time and on the same frequency. When listening to the raw DMR data with an analog receiver, the buzz of raw data sounds like a DMR repeater on the air.

I'll try this out with my GD-77 and my PD982 radios.

UPDATE: I tried using the TDMA Direct Mode on my Hytera PD982 radios and my GD-77. I can confirm that the TDMA simplex mode on the GD-77 DOES work.

The GD-77 was set up with 3 simplex channels on 446.075 CC1 TG99 for testing. 446.075 CC1 TG99 TS1 is the DMR-MARC simplex channel.
446.075 CC1 TG99 TS1, TDMA simplex mode not enabled on this channel. This is a normal simplex channel setup in a DMR radio.
446.075 CC1 TG99 TS1, with TDMA simplex mode enabled.
446.075 CC1 TG99 TS2, with TDMA simplex mode enabled.

A pair of PD982 radios were programmed similarly. One PD982 was set on 446.075 CC1 TG99 TS1 with TDMA Direct Mode enabled. The second PD982 was set on 446.075 CC1 TG99 TS2 with TDMA Direct Mode Enabled.

I also had a Hytera X1p handheld on 446.075 CC1 TG99 TS1. The X1p does not have Hytera's TDMA Direct Mode.

Results:
Keying up the GD-77 without TDMA simplex mode enabled allowed me to be heard on both PD982 radios at the same time.
Keying up the GD-77 on TS1 in TDMA simplex mode allowed me to be heard only on the PD982 set to TS1.
Keying up the GD-77 on TS2 in TDMA simplex mode allowed me to be heard only on the PD982 set to TS2.
The X1p heard the GD-77 in all 3 cases since the X1p does not have TDMA Direct Mode.

Keying up BOTH PD982 radios simultaneously allowed me to be heard on the GD-77 from one PD982 radio at a time, depending on which TS the GD-77 was listening on while in TDMA simplex mode. Listening on TS1 only heard the PD982 set to TS1. Listening on TS2 only heard the PD982 set to TS2. Both PD982 radios were keyed together and remained keyed during these tests. Listening on the GD-77 without TDMA simplex mode enabled only heard the PD982 transmitting on TS1. Without TDMA simplex mode enabled, the GD-77 ignored the PD982 transmitting on TS2 because the channel was programmed for TS1.

Keying up the GD-77 on TS1 while keying a PD982 on TS2 resulted in hearing myself on the other PD982 set on TS1. The PD982 on TS1 hearing the GD-77 on TS1 was not bothered at all by the PD982 transmitting on TS2. Keying up the GD-77 on TS2 while keying a PD982 on TS1 resulted in hearing myself on the PD982 set to TS2. The PD982 hearing the GD-77 on TS2 was not bothered at all by the other PD982 transmitting on TS1.

I can confirm TDMA simplex mode in the GD-77 definitely DOES work.

 

[jonwienke]

Now if they could just implement a single-frequency repeater mode where input was on TS1 and output was on TS2, and an "either" option for specifying the RX TS, then you could set up a repeater and use the same channel programming for simplex and repeater operation.

 

[n1das]

Now if they could just implement a single-frequency repeater mode where input was on TS1 and output was on TS2, and an "either" option for specifying the RX TS, then you could set up a repeater and use the same channel programming for simplex and repeater operation.

Single Frequency Repeater (SFR) mode is an option with a Hytera PD982. I don't have the SFR option in my PD982s. I'm planning to get it eventually.
https://youtu.be/gHRXMVr2JsI

 

[N4GIX]

Now if they could just implement a single-frequency repeater mode where input was on TS1 and output was on TS2, and an "either" option for specifying the RX TS, then you could set up a repeater and use the same channel programming for simplex and repeater operation.

I don't believe the GD-77 is sophisticated enough to receive and transmit at the same time, as too much of the circuitry is shared.

 

[jonwienke]

I don't believe the GD-77 is sophisticated enough to receive and transmit at the same time, as too much of the circuitry is shared.

It's not necessary. Listen to TS 1, then retransmit whatever is heard on TS 2. The whole point of a single-frequency repeater is that simultaneous RX and TX is never necessary, which eliminates the need for duplexers or special filtering.

 

[N4GIX]

It's not necessary. Listen to TS 1, then retransmit whatever is heard on TS 2. The whole point of a single-frequency repeater is that simultaneous RX and TX is never necessary, which eliminates the need for duplexers or special filtering.

That would require that they develop a recording function, which may not be possible due to memory limitations.

In any case, if all you want is a simple "store-and-forward" system, using different time slots isn't even necessary. In fact it would only add another layer of needless complexity.

 

[n1das]

It's not necessary. Listen to TS 1, then retransmit whatever is heard on TS 2. The whole point of a single-frequency repeater is that simultaneous RX and TX is never necessary, which eliminates the need for duplexers or special filtering.

N4GIX is saying the GD-77 doesn't have single frequency repeater (SFR) mode like a Hytera PD98x radio has. The GD-77 has TDMA simplex mode but doesn't have SFR mode.


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[jonwienke]

That would require that they develop a recording function, which may not be possible due to memory limitations.

Again, no. The radio has to be able to buffer at least one timeslot's worth of bits to encode and decode between bits and audio. 33ms worth of bits is well within the buffering capability of the radio. Any DMR radio could function as a single-frequency repeater, if the manufacturer bothered to add the capability to the firmware.