Narrow Band Frequencies

[kd5pqv]

Will ham radios monitor narrow band frequencies

[N1BHH]

You need to expand your query, what are you talking about?

[nd5y]

Will ham radios monitor narrow band frequencies

Some newer VHF/UHF FM ham radios have NFM mode (12.5 kHz bandwidth/2.5 kHz deviation).
If you have one that doesn't, you can still hear NFM stations, they will just have lower audio.

No VHF/UHF FM ham radios that I know of will tune 2.5, 7.5 or 6.25 kHz steps.
If you have one that doesn't, you can still hear NFM stations, they will just be slightly off frequency.

[rescuecomm]

I thought the Kenwood TM271 could step 2.5 khz? There was something out on the web about the PL/DPL decode not working fast enough on narrowband and causing one to miss the first second or so of a transmission. I don't have one so this is definitely second hand information. Amatuer radios can receive on-frequency narrowband with only a reduced audio level. The 2.5 khz step is a problem for my Icom F30GS on certain frequencies. A couple of the VTAC frequencies give an error if you program them.

Bob

[nd5y]

Originally Posted by rescuecomm

I thought the Kenwood TM271 could step 2.5 khz?

I just looked at the manual and it does. It also does narrow FM. That is the first ham rig I have seen like that, but I haven't been keeping up with them lately.

[SlipNutz15]

I have a question. With all the narrowbanding going on, are amateur frequencies exempt from this or will amateur frequencies end up having to be narrow banded as well?

[N_Jay]

Originally Posted by SlipNutz15

I have a question. With all the narrowbanding going on, are amateur frequencies exempt from this or will amateur frequencies end up having to be narrow banded as well?

Yes and no.

I am sure some Amateur systems will go narrowband, as I am sure that it will not be legally required. (as few technical details are in Amateur).

[N1BHH]

Narrow banding is actually more of a bandwidth narrowing. Instead of a deviation of ~5 kilohertz in many current radios, the more modern versions are capable of 2.5 kilohertz deviation. In some areas of the country some repeaters use narrow bandwidth to avoid interference with other machines in the area and also as a way to add more repeaters for an area.

But there really isn't such a need in most parts of the country, plus there really isn't much support for additional repeaters, despite any conceived growth in numbers of amateur radio operators. It is conceivable to add more repeater pairings, but that would mean some people who are on limited budgets couldn't afford to buy a more modern radio with narrow capabilities.

[azlooker]

FCC and ARRL are working on a plan right now to incorporate narrowband technology. I remember an article either in QST or the ARRL email bulletin just recently.

[zz0468]

Originally Posted by azlooker

FCC and ARRL are working on a plan right now to incorporate narrowband technology. I remember an article either in QST or the ARRL email bulletin just recently.

That almost doesn't make sense. Unless these narrowband technologies being proposed use modulation methods that are currently not authorized for amateur use (and I can't imagine what that would be), the FCC is almost completely unconcerned about what narrow bandwidth is used in the repeater sub-bands. This would more be a concern between the local frequency coordinating bodies, and the ARRL national band plans.

An example of narrow band operation taking place can be seen in California, where the 900 MHz band plan calls for 13K6F3E, with a max deviation of 2.5 KHz, and a max audio frequency of 3 KHz. This is primarily done because that's what the available radios will do, not some FCC or ARRL mandate. Judging from the articles on the net I've seen describing how to modify existing 900 MHz radios for 5 KHz deviation, Southern California seems to be the only place that I'm aware of that mandates narrow band operation through the local frequency coordinator.