Using Amateur Radio to monitor APCO P25 conventional

Jim1348 · #1 (**permalink**) 04-24-2005, 12:25 AM

We have just added a mixed-mode analog and APCO P25 amateur radio repeater to the Twin Cities (MN) area. It will be interesting to see if in the future any amateur radio manufacturers ever make a dual-mode amateur radio that will operate on both analog and APCO P25. I have got to imagine that the total number of APCO P25 repeaters on ham frequencies in the US is a small number. On the other hand, perhaps this is the wave of the future. I seem to recall Alinco having a digital mode ham radio, but I don't think it it APCO P25. I also seem to recall Icom having some sort of digital modulation on some rigs, but similarly not APCO P25. At least APCO P25 is an open, non-proprietary standard. And if amateur gear ever does get it we could listen to non-amateur stuff out of band as we do now with analog. This won't help much with the trunked stuff, but it is a start.

WatnNY · #2 (**permalink**) 04-24-2005, 12:40 AM

I thought you couldn't "scramble" any Ham radio communications ?????

Mike

K5MAR · #3 (**permalink**) 04-24-2005, 12:45 AM

Quote:

Originally Posted by WatnNY

I thought you couldn't "scramble" any Ham radio communications ?????

Mike

APCO P-25 is digital modulation, not digital encryption.

Mark S.

WatnNY · #4 (**permalink**) 04-24-2005, 12:50 AM

Roger that. Considering the reception is apco 25 digital, which is not readily "listen-able" to a normal ham radio, wouldn't it be considered "scrambling"?

Mike

jrjarna · #5 (**permalink**) 04-24-2005, 01:03 AM

APCO is just another mode... as would be morse or RTTY, except it is a digital transmission. Being "readily listenable" is not a consideration of FCC Regs on ham radio....unless you are encrypting or enciphering you communications so that others may not intercept them. As APCO has clearly defined protocols for digital transmission, anyone could intercept them given the appropriate receiver. The same argument could be made for CW.... some people cant read it, but it is a commonly used mode of transmission. Digital transmissions have been used for years in amateur radio and are clearly acceptable transmission types.

Jason
N4TPQ

K5MAR · #6 (**permalink**) 04-24-2005, 01:21 AM

Example:

Alinco markets a digital board for select 2m and 70cm radios. These boards are not a standardized digital format like P-25, in other words, to monitor the transmissions you have to have an Alinco radio equipped with the optional digital board. BUT, the digital format being used is a public record, readily available from Alinco. This makes it acceptable under FCC regulations.

Mark S.

WatnNY · #7 (**permalink**) 04-24-2005, 09:18 AM

I understand better now, thanks.

Mike

Voyager · #8 (**permalink**) 04-24-2005, 02:19 PM

Quote:

Originally Posted by WatnNY

Roger that. Considering the reception is apco 25 digital, which is not readily "listen-able" to a normal ham radio, wouldn't it be considered "scrambling"?

Mike

Two problems with your statement.

First, RTTY, packet, and ATV are also not 'listenable' with a normal ham radio either. You have to use an external converter. Converters for P25 exist, too.

Also, let's not forget that P25 scanners now exist. The public CAN monitor a P25 transmission.

The rule you cite is about SCRAMBLED transmissions. You cannot encrypt your signal. P25 is not encryption or scrambling in ANY form (as was mentioned above).

Joe M.

hotdjdave · #9 (**permalink**) 05-10-2005, 04:28 AM

Does anyone know where to get an APCO-25 converter for scanners. Particullary for the ICOM PCR-1000?

Dave. :?:

PJH · #10 (**permalink**) 05-10-2005, 04:51 AM

A little clarification...

Encypted communications is not permitted by the FCC in the HA bands. Digital communications, as long as they are an open standard (in which the P25 is) are permissable.

RTTY and other such modes are supported internally by a few high end ham radios and for the purposes of this thread would be considered "listenable".

Any attempt to obscure the meaning of a transmission is what is in violation of the FCC regs. In all such cases above, that's not what is going on.

P25 is no different than what ICOM is trying to do with DStar which uses the AMBE codec.

There are quite a few P25 HAM machines in use, although they would be in the 1 to less than 1% of the total of ham repeaters in use. I can think of at least 10 that I know about on the east coast.

For the the last post, there are no known "converters" for APCO25, your pretty much buying a Uniden of Radio Shack scanner that is built of decoding IMBE.

BANDIT · #11 (**permalink**) 05-10-2005, 07:32 PM

How about the one AOR makes for a receiver with a 10.7 IF. Or was it 10.8 don,t remember off the top of my head. But it will work with the R8500 and other receivers. Only problem is it cost as much as a digital scanner...

JnglMassiv · #12 (**permalink**) 05-10-2005, 10:34 PM

This is presently being discussed on Batlabs.

It seems the AOR unit Bandit mentions does the job with recievers with a 10.7MHz IF out:
The AOR ARD25

wogggieee · #13 (**permalink**) 09-15-2007, 10:14 AM

Quote:

Originally Posted by Jim1348

We have just added a mixed-mode analog and APCO P25 amateur radio repeater to the Twin Cities (MN) area. It will be interesting to see if in the future any amateur radio manufacturers ever make a dual-mode amateur radio that will operate on both analog and APCO P25. I have got to imagine that the total number of APCO P25 repeaters on ham frequencies in the US is a small number. On the other hand, perhaps this is the wave of the future. I seem to recall Alinco having a digital mode ham radio, but I don't think it it APCO P25. I also seem to recall Icom having some sort of digital modulation on some rigs, but similarly not APCO P25. At least APCO P25 is an open, non-proprietary standard. And if amateur gear ever does get it we could listen to non-amateur stuff out of band as we do now with analog. This won't help much with the trunked stuff, but it is a start.

What freq is the repeater on, who is running it, and what repeater did it replace. I'm assuming from what I've heard in the past that it is 2m, i know that's not the best thing, and i believe that all the available pairs are taken in this area, so it would probably have to replace something already there.

N_Jay · #14 (**permalink**) 09-15-2007, 10:36 AM

Quote:

Originally Posted by K5MAR

Example:

Alinco markets a digital board for select 2m and 70cm radios. These boards are not a standardized digital format like P-25, in other words, to monitor the transmissions you have to have an Alinco radio equipped with the optional digital board. BUT, the digital format being used is a public record, readily available from Alinco. This makes it acceptable under FCC regulations.

Mark S.

Can you re-write that so it makes sense?

K5MAR · #15 (**permalink**) 09-15-2007, 03:08 PM

Quote:

Originally Posted by N_Jay

Can you re-write that so it makes sense?

Instead of worrying about a 2 year old post, I suggest you visit both the Alinco website and the FCC's Part 95 rules. Should be easy enough for you to do. There's even a place where you can take the FCC ID number and look at the paperwork submitted to the FCC when the radios were certified. I imagine there will be something there about digital audio.

BTW, whwy did it take two years for you to decide something wasn't clear about that post. I don't see where anybody else had any problems understanding it.

Mark S.

Grog · #16 (**permalink**) 09-15-2007, 03:51 PM

Holy old post Batman !!!!

loumaag · #17 (**permalink**) 09-15-2007, 03:57 PM

And this is why opening up old posts to ask a "sort of" related question is a bad idea. People don't bother to look at dates, they just read and go.

I am moving the slightly related question and the single answer to it so far to it's own thread in the Icom forum.