[GreenKeys] FCC substitutes bandwidth limit for baud rate limit on HF

[W2HX]

> High fidelity AM seems permissible.
I don't read it that way, but I hope I'm wrong. It mentions "communications quality A3E emission" which, to me, is narrower than "broadcast quality"


73 Eugene W2HX
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-----Original Message-----
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> On Behalf Of Harold Hallikainen via GreenKeys
Sent: Wednesday, November 15, 2023 1:50 PM
To: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] FCC substitutes bandwidth limit for baud rate limit on HF

I agree that the new emission limit applies only to RTTY and data.

For example, for 40 meter RTTY and data, we are referred to 73.307(3) and 73.307(f)(9).

This report and order revises 73.307(f)(3) from:

(3) Only a RTTY or data emission using a specified digital code listed
   in § 97.309(a) of this part may be transmitted. The symbol rate must not
   exceed 300 bauds, or for frequency-shift keying, the frequency shift between mark and space must not exceed 1 kHz.

TO:

(3) Only a RTTY or data emission using a specified digital code listed in § 97.309(a) may be transmitted. The authorized bandwidth is 2.8 kHz except in the 2200 m band and 630 m band. In the 2200 m band and the 630 m band the symbol rate must not exceed 300 bauds, or for frequency-shift keying, the frequency shift between mark and space must not exceed 1 kHz.


73.307(f)(9) remains unchanged at:
(9) A station having a control operator holding a Novice or Technician
   Class operator license may only transmit a CW emission using the international Morse code.

Looking at 40 meter phone and image, we find it unchanged and referencing
73.307(f)(1) and 73.307(f)(2) which state:

(1) No angle-modulated emission may have a modulation index greater
   than 1 at the highest modulation frequency.

   (2) No non-phone emission shall exceed the bandwidth of a
   communications quality phone emission of the same modulation type. The total bandwidth of an independent sideband emission (having B as the first symbol), or a multiplexed image and phone emission, shall not exceed that of a communications quality A3E emission.

Note also that 97.307(a) states:

(a) No amateur station transmission shall occupy more bandwidth than
   necessary for the information rate and emission type being transmitted, in accordance with good amateur practice.

So, for voice, there is no specific bandwidth limit. High fidelity AM seems permissible.

As mentioned previously, once you move to a digital, it seems to matter little what the content is. For example, is Hell Feldfernschreiber data or image?

Harold
https://w6iwi.org




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