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Re: Update 9th Feb

Posted: Mon Feb 10, 2020 9:07 pm
by VK3KYY
YT5HOK wrote:
Mon Feb 10, 2020 2:43 pm
4I1RAC wrote:
Mon Feb 10, 2020 12:28 pm
... just that some stations do have their TA specified as just names, which can be confusing during QSOs (e.g., if you don't have their callsigns memorized).
As far as I know, Talker Alias coming from BrandMeister always contains callsign. That is mandatory and can't be changed. Only APRS Text, under Self Care, can be and is encouraged to be changed from default DMR ID: XXXXXXX to name, or something meaningful.

I occasionally see BM sending other stuff instead if the callsign, but AFIK BM is supposed to always sent them callsign.

Hence I set the lookup order to be TA last, and have all the VK and also the most active UK and USA stations in my DMR ID database. As the DMR ID data always has the name as well as the callsign

Re: Update 9th Feb

Posted: Tue Feb 11, 2020 5:16 am
by 4I1RAC
VK3KYY wrote:
Mon Feb 10, 2020 9:07 pm
YT5HOK wrote:
Mon Feb 10, 2020 2:43 pm
4I1RAC wrote:
Mon Feb 10, 2020 12:28 pm
... just that some stations do have their TA specified as just names, which can be confusing during QSOs (e.g., if you don't have their callsigns memorized).
As far as I know, Talker Alias coming from BrandMeister always contains callsign. That is mandatory and can't be changed. Only APRS Text, under Self Care, can be and is encouraged to be changed from default DMR ID: XXXXXXX to name, or something meaningful.

I occasionally see BM sending other stuff instead if the callsign, but AFIK BM is supposed to always sent them callsign.

Hence I set the lookup order to be TA last, and have all the VK and also the most active UK and USA stations in my DMR ID database. As the DMR ID data always has the name as well as the callsign
Thanks for the tip, Roger. Yes I see all sorts of TA data too via BM, especially on worldwide. I have limited the db import to 6 characters so I only get the callsign (this gets me 25k contacts or so from the Philippines, Australia, and the US). I guess it's a trade-off between more contacts or better contact details.

Re: Update 9th Feb

Posted: Tue Feb 11, 2020 5:53 am
by VK3KYY
Yes. Its a trade off between the size of the database and the number of characters.

The problem with the storage of the DMR DB is that the current location for the calibration is directly after the end of the DMR ID section in memory
So we can't increase the size of the DMR ID system without moving the calibration date somewhere else.

And moving the calibration is a big risk for anyone who doesnt know what they are doing, as it can brick the radio if its done wrong :-(

If you are handy with a soldering iron, its posible to remove the 1Mb flash memory chip in the radio and fit a 8Mb or I think even a 16Mb chip in its place.
The 8Mb chip is actually larger and you have to bend the pins in under the chip to get it to connect to the existing pads on the PCB, but it is possible to do.

I have 2 radios with 8Mb chips in them, which Radioddity did as special's when they were thinking of producing a updated GD-77, but in the end they decided not to both, because they make so little money on the GD-77 that the tooling costs of getting a different PCB made, would not be cost effective.

Re: Update 9th Feb

Posted: Tue Feb 11, 2020 9:39 am
by EA3BIL
If you are handy with a soldering iron, its posible to remove the 1Mb flash memory chip in the radio and fit a 8Mb or I think even a 16Mb chip in its place.
What is the estimated contacts capacity for 8Mb / 16Mb chips?

120.000 on 8Mb
240.000 on 16Mb
??

Thank you.

Re: Update 9th Feb

Posted: Tue Feb 11, 2020 10:25 am
by VK3KYY
Currently it takes 4 bytes + number of characters per record in the DB.

Plus 12 bytes in the header.

So 8Mb = 8 * 1024 * 1024 bytes = 8388608

and at 20 bytes per record that would be 8388608 /20 = 419430 records (IDs)

One other option with the current memory, apart from moving the calibration table, which we could easily do.
Is to compact the text of the 16 characters, because the text only contains the letters a-z, A-Z and the numbers 0 - 9, plus the space character.

i.e 26+26+10+1 = 63 chars

If we also include the full stop (period) .

Thats 64 characters, which is 6 binary bits, hence we are wasting 2 bits per byte.

I think some radios use DMR ID compression where they pack the characters like this

11111122 22223333 33444444

hence 4 characters can be squeezed into 3 bytes, which gives 1/3 more storage capacity.