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Author Topic: How exactly is 219MHz band supposed to be used?  (Read 622 times)
N2QMU
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Posts: 6




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« on: May 22, 2019, 10:19:20 PM »

I've always wondered about this deserted island of the 1.25 meter band.
(See it in ARRL band charts in issues of QST since maybe 1990 until now.)

What sort of amateur radio station is permitted to use 219-220 MHz?
Please describe in detail an example of properly operating there.

(I imagined maybe something like packet radio with old 56k baud or DSL modems.)
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K0CWO
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Posts: 550




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« Reply #1 on: May 22, 2019, 10:32:07 PM »

Look at the Icom band plan PDF.  It is similar to 2 meters and 440 in that 220 has band segments for CW, FM repeater, FM simplex, and SSB.

73, k0cwo
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N2QMU
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Posts: 6




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« Reply #2 on: May 22, 2019, 10:52:21 PM »

Sorry I am referring only to the unique and mysterious orange band in the center right of this chart which is isolated from the rest of the band and marked as only for "digital message forwarding":

https://qrznow.com/wp-content/uploads/2018/10/Band_Chart_ham_hamradio.jpg

Still wondering how "digital message forwarding only on 219MHz" would be done correctly.
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W9IQ
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Posts: 3542




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« Reply #3 on: May 22, 2019, 11:21:45 PM »

The 219-220 segment is a shared allocation with Marine AMTS stations and others. There are several restrictions that must be followed and requirements to be met if you are going to operate in this segment. See CFR 97.303(l) for the details.

Regarding the allowed mode, it is "restricted to amateur stations participating as forwarding stations in fixed point-to-point digital message forwarding systems, including intercity packet backbone networks". Any digital mode would be permitted as long as the only role of the transmission is to forward messages and in doing so, it meets all other stated conditions of that subpart.

- Glenn W9IQ

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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
W6RZ
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Posts: 365




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« Reply #4 on: May 22, 2019, 11:33:27 PM »

In addition to 97.303(l) that W9IQ referenced, there are two more sections.

97.307

(13) A data emission using an unspecified digital code under the limitations listed in ยง97.309(b) also may be transmitted. The authorized bandwidth is 100 kHz.

97.313

(h) No station may transmit with a transmitter power exceeding 50 W PEP on the 219-220 MHz segment of the 1.25 m band.

I'd say it's possible there are zero amateur stations on the band, but that's just a guess. The 100 kHz bandwidth rule pretty much ruins it for any serious backbone link.

However, there doesn't seem to be a baud rate limit, so you could effectively use the 100 kHz. With some high order modulation like 32APSK, you could have a 370 kbps link.

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N2QMU
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Posts: 6




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« Reply #5 on: May 23, 2019, 02:04:24 AM »

Very interesting thank you.
I guess it's probably true there are no amateur stations In that band now,
but maybe there might have been a perceived need for them in the 1990s
wherever the Internet had barely reached yet, and a 100KHz link would have
provided a significant increase in data bandwidth for them then. Or maybe
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W9IQ
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« Reply #6 on: May 23, 2019, 02:45:25 AM »

I have not heard of any activity on this segment.

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
N2QMU
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« Reply #7 on: May 23, 2019, 03:04:23 AM »

Me neither.

... Or maybe (the following was dropped)
219 was only added to the band for a feeling that we got something else
(that we'd never use) for losing 220 and 221.
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WA3SKN
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« Reply #8 on: May 25, 2019, 04:56:05 PM »

As I recall, this was shared with commercial paging. (memory is poor though). Probably both defunct by now.

-Mike.
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