[Allstar Digital] MMDVM Lessons learned so far.

[REDBUTTON_CTRL]

OK I misspoke. DMR is supposed to occupy a12.5 KHz mask. So the 2 slots 
are supposed to acheive 1 voice channel per 6.25 KHz or the "Spectral 
Equivalency".
The modulation is actually C4FM but is sent in 2 bursts of data for time 
division.

I was thinking of Tetra which occupies 25 KHz and 4 slots to achieve the 
same spectral efficiency.

On 1/9/2016 6:41 PM, Corey Dean wrote:
> That is the part I was missing.  Thank you!  That clarified things up for me!
>
> Sent from my iPhone
>
>> On Jan 9, 2016, at 6:33 PM, REDBUTTON_CTRL<jrorke at cogeco.ca>  wrote:
>>
>> Since DMR uses a wide band channel to 2 the 2 slots, therefore you will need a radio that does wide band (5khz/25 khz).
>>
>> Other C4FM modulation schemes use narrow band like P25 and (Con)fusion.
>> RQ
>>
>>> On 1/9/2016 5:57 PM, Steve Zingman wrote:
>>> We have not narrowed that down yet. We are Using Tait T2xxx radios. One of the things we need to try is both the wide and narrow setting. We have not et even confirmed that 3.88 is optimal.
>>>
>>>> On 01/09/2016 05:52 PM, Corey Dean wrote:
>>>> So I am assuming a wide band transmitter instead of narrow?
>>>>
>>>> Sent from my iPhone
>>>>
>>>>> On Jan 9, 2016, at 5:47 PM, Steve Zingman<szingman at msgstor.com>  wrote:
>>>>>
>>>>> Mike and I have been working with the MMDVM and the Home Brew Repeater code for a couple of weeks.
>>>>> It's very early in the process and I think that unless you like to try to hit at least 3 moving targets, I suggest people wait. The MMDVM is a  Arduino  Due and a small analog board. The modem firmware runs on the Due. The analog board does some filtering and level control. We are running a early prototype board from Jim KI6ZUM. Jim has some new boards in the works, so right now waiting or build your own is the only choice.
>>>>>
>>>>> The software is early and buggy, as any new software is. Jonathan G4KLX has done a phenomenal job so far and it only will get better. The test software ONLY works in duplex mode, which is a problem because if your transmit data is not right, you will not get too far with receive. Kind of a catch 22. Jonathan G4KLX says that the deviation should be 3.88 KHz. So on my IFR 1200S that works out to a hair under 4KHz. (analog meter). Now that we have the transmit working OK, not great but OK, we will start on receiver.
>>>>>
>>>>> More to follow.
>>>>>
>>>>> For INAD, Steve N4IRS
>>>>> -- 
>>>>> "Anything is possible if you don't know what you are talking about."
>>>>> 1st Law of Logic
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