SA GRN Emission Designators

Post Reply
Mike Alpha
Posts: 672
Joined: Thu Aug 14, 2008 8:22 pm

SA GRN Emission Designators

Post by Mike Alpha » Fri Nov 10, 2017 10:45 pm

These are the emission designators on one of the SA GRN sites at Port Adelaide. 3 different transmission types. Same on all other sites.

416.1875 MHz 10K1FXW 26/Aug/2010 T

416.275 MHz 10K1G9W 12/Apr/2017 T

416.4375 MHz 10K1F3E 26/Aug/2010 T

Analogue, P25 and P2 maybe?

Mike

User avatar
Bigfella237
Posts: 1895
Joined: Fri Feb 26, 2010 3:11 pm
Location: In geosynchronous orbit above the Far South Coast of NSW, Australia

Re: SA GRN Emission Designators

Post by Bigfella237 » Sat Nov 11, 2017 10:19 am

G'day Mike,

I'm not really up on emission designators but I don't know how much you can depend on them being accurate on the ACMA, I don't think they get updated like they should?

I found some info via google which indicates:
  • 10K1F3E should be FM analog only
    10K1FXW should be FM with a "Combination of multiple information types"
    10K1G9W is shown as "Phase modulation" with a "Combination of multiple information types"
Considering P25 utilizes FM, I'd guess either the 10K1FXW or 10K1F9W designator should be used? Typically "Phase modulation" would be used for something like GSM, not P25.

The Phase 1 NSWGRN freqs look to be a mixture of 10K1F3E (I assume these haven't been updated from the old analog days) and 10K1F9W

The VICMMR is Phase 2 and seems to be 10K1F3E (again these are analog designators??), while the VICRMR is Phase 1 and 10K1F9W

Finally, the QLDGWN assignments I looked at are also 10K1F9W and their system is mainly Phase 2

So I think the only thing I've really figured out is that someone is very slack when it comes to keeping the ACMA data up to date!

Andrew

citabria
Site Admin
Posts: 1064
Joined: Thu Aug 14, 2008 8:22 pm

Re: SA GRN Emission Designators

Post by citabria » Sat Nov 11, 2017 11:02 am

Emission designators are an artform, not a science. Take them with a grain of salt, especially when they come from the radcom database.

Frequency and phase modulation are very closely related. In fact, it is impossible to tell whether the signal was produced by a frequency modulator or phase modulator by analyzing the received signal unless specific information about the baseband signal is given. P25 can be considered both phase or frequency modulation, and in fact, a phase demodulator with work just as well as an FM demodulator on P25 Phase 1.

Phase and frequency have the relationship that phase is the integral of the frequency or frequency is the derivative of the phase. When you frequency modulate a signal, you are phase modulating it too, and vice versa. With this is mind, it's a bit silly to differentiate the two with separate emission designators.

The only thing that matters to ACMA, and the only part of the emission designator that is actually correct is the occupied bandwidth (10K1) as that's the part that determines the spectrum usage and interference potential of a signal. The rest - F3E, FXW, G9W... well, use it at your own peril.

If you want to use them from radcom to determine whether a signal is P25 phase 1 or two or even analog, then you really need a crystal ball or the ability to read the mind of the person that filled out the paperwork when the license was submitted.

Post Reply