Re: [digitalradio] NBFM Packet & Voice on HF?
My father had a Hallicrafters HT-9 that did FMbut he never used it on FM as long as I remember. That line came to the market after WW II, if I remember well. He sold his Hallicrafters transmitter in 1961 or so...Johnson HF transmitters did not have any measure of FM emissions. Maybe some old timer might tell us if it was a feature waiting for a regulation that did not show up in a timely manner Jose, CO2JA kd4e wrote: > Anyone familiar with NBFM Packet activity on 10M, 29,100 - 29,300MHz > ? > > I came upon an old Sonar VFX 680 NBFM/CW exciter that covers 160-2M > and it got me wondering why NBFM is not included across the Ham HF > spectrum bandplan. I don't believe it is any wider than an AM signal. > > > Collins Model 75A-1 is an AM/CW/NBFM receiver from 1946, so NBFM > would appear to have once been permitted. > > -- > > Thanks! & 73, doc, KD4E
Re: [digitalradio] NBFM Packet & Voice on HF?
> Paul L Schmidt, K9PS wrote: > Now, if someone hadn't confused the regulation-by-bandwidth rulemaking > proposal by putting unrelated changes in automatic control in the same > proposal, it might have been successful. Had it been, we'd be able to be > talking to someone on SSB, and blast them a digital file during the QSO > without having to change frequency to the data sub-band. And it *wouldn't* > make any difference what kind of information you were transmitting via > a particular mode... But all the outcry over the automatic control changes > proposed at the same time left us as with the status quo -- the antiquated > regulation that doesn't fit the current technology. Can you draft a request for a sensible change? -- Thanks! & 73, doc, KD4E ~~ Projects: http://ham-macguyver.bibleseven.com Personal: http://bibleseven.com ~~
Re: [digitalradio] NBFM Packet & Voice on HF?
--- Danny Douglas <[EMAIL PROTECTED]> wrote: > Why is that? FM is the carrier, afsk is the mode. > Just as SSB is the > carrier for an AFSK signal. If you can run AFSK on > SSB in the other bands, > why not 10? Does it specifically say NBFM only for > voice? > > > Danny Douglas N7DC > ex WN5QMX ET2US WA5UKR ET3USA > SV0WPP VS6DD N7DC/YV5 G5CTB all > DX 2-6 years each You do not understand what hapens when you send audio tones for rtty into a ssb transmitter. The end result of what comes out of the transmitter can not be distinguished from a true FSK transmitter. That means in effect the transmitter is not putting out AFSK but just FSK. On todays modern transceivers many of them use an audio tone in the USB mode to generate CW. In effect you are really transmitting FSK and not AFSK. If you switch the rig (as many multimode rigs can) to AM or FM then you are transmitting AFSK. This makes it not legal in the data frequencies of the low bands. It's here! Your new message! Get new email alerts with the free Yahoo! Toolbar. http://tools.search.yahoo.com/toolbar/features/mail/
Re: [digitalradio] NBFM Packet & Voice on HF?
Danny Douglas wrote: > Why is that? FM is the carrier, afsk is the mode. Just as SSB is the > carrier for an AFSK signal. If you can run AFSK on SSB in the other bands, > why not 10? Does it specifically say NBFM only for voice? That would be an F2D emission. Legal on frequencies where 97.307(f)(8) is referenced in the tables of 47 CFR 97.305 -- essentially 6 meters and up; that section adds F2D to the list of data modes described in 97.3(c)(2) AFSK over an SSB rig would either be an F1 emission (if you're looking at the actual signal being transmitted) or J2 (if you're looking at the method by which it's generated). Both are legal. Now, if someone hadn't confused the regulation-by-bandwidth rulemaking proposal by putting unrelated changes in automatic control in the same proposal, it might have been successful. Had it been, we'd be able to be talking to someone on SSB, and blast them a digital file during the QSO without having to change frequency to the data sub-band. And it *wouldn't* make any difference what kind of information you were transmitting via a particular mode... But all the outcry over the automatic control changes proposed at the same time left us as with the status quo -- the antiquated regulation that doesn't fit the current technology. - ps
Re: [digitalradio] NBFM Packet & Voice on HF?
Why is that? FM is the carrier, afsk is the mode. Just as SSB is the carrier for an AFSK signal. If you can run AFSK on SSB in the other bands, why not 10? Does it specifically say NBFM only for voice? Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: "Paul L Schmidt, K9PS" <[EMAIL PROTECTED]> To: Sent: Thursday, February 01, 2007 6:08 PM Subject: Re: [digitalradio] NBFM Packet & Voice on HF? > I was just looking in part 97, (regarding the legality of ISB), and > noticed something else... > > In the US, even though "regular" NBFM is legal above 29 MHz, it's only > legal for voice. The entire 10-meter band is still split up between > RTTY/Data and Voice/Image like the rest of the HF bands.. > > So AFSK over FM on 29.xx MHz isn't legal here anyway. > > Paul L Schmidt, K9PS wrote: > > > > I haven't tried AFSK over FM on 10 meters, but given what I've heard > > on 10M FM during the last sunspot maximum, I would definitely agree > > with you that the propagation characteristics -- which are obnoxious > > enough on FM voice -- would probably destroy a packet signal. > > > > > > Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org > > Our other groups: > > http://groups.yahoo.com/group/dxlist/ > http://groups.yahoo.com/group/themixwgroup > http://groups.yahoo.com/group/contesting > http://groups.yahoo.com/group/wnyar > http://groups.yahoo.com/group/Omnibus97 > > > Yahoo! Groups Links > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.432 / Virus Database: 268.17.18/662 - Release Date: 1/31/2007 3:16 PM > >
Re: [digitalradio] NBFM Packet & Voice on HF?
I was just looking in part 97, (regarding the legality of ISB), and noticed something else... In the US, even though "regular" NBFM is legal above 29 MHz, it's only legal for voice. The entire 10-meter band is still split up between RTTY/Data and Voice/Image like the rest of the HF bands.. So AFSK over FM on 29.xx MHz isn't legal here anyway. Paul L Schmidt, K9PS wrote: > > I haven't tried AFSK over FM on 10 meters, but given what I've heard > on 10M FM during the last sunspot maximum, I would definitely agree > with you that the propagation characteristics -- which are obnoxious > enough on FM voice -- would probably destroy a packet signal. >
Re: [digitalradio] NBFM Packet & Voice on HF?
There was some packet activity on 29 MHz in the 90's . While I could do a LOT of forwarding at 1200 baud on 28.18 MHz at 1200 baud using a SSB radio, I was NEVER lucky to get a connection at 1200 baud FM AFSK, even when I heard some of them. SNR was too bad. The numbers tell that such a link is entirely disadventageous using a "subcarrier" on FM against raw 1200 baud FSK over a SSB radio. Jose, CO2JA --- Paul L Schmidt, K9PS wrote: > KV9U wrote: > > Good points, Paul, > > > > One thing that I found with longer distance FM signals on HF, even > > though 10 meters can be close to the MUF when it is open, is that > > there is a lot of frequency inversion or other anomalies from the > > ionosphere that make it rather annoying and unsatisfactory. This is > > not true with narrow bandwidth modes such as SSB. If you were just > > using FM for local communications it is much more satisfactory and > > we have found it can compete well with 2 meter repeaters in some > > cases. Instead of dropping out, the signal just gets weaker, but > > often still readable. > > Given the comment in the original posting about the older receiver > supporting NBFM and therefore it must "have once been permitted", I > was reading the main question as the one of legality. > > I haven't tried AFSK over FM on 10 meters, but given what I've heard > on 10M FM during the last sunspot maximum, I would definitely agree > with you that the propagation characteristics -- which are obnoxious > enough on FM voice -- would probably destroy a packet signal. > > During the sunspot minimum, though, it might provide convenient local > links, although a different modulation scheme would give better > results even for that. > > > This is almost like the attempt to use a mode such as digital voice > > on the HF bands. It needs a very good S/N ratio to stay locked in. > > > > Even digital SSTV/FAX modes which fit into a regular narrow voice > > bandwidth will display almost continuous damage to at least some of > > the tones at any one time when you observe them on the waterfall. > > I've watched lots of MT63 on the lower end of the HF spectrum, and > observe the diagonal lines from the fading so some extent *most* of > the time. With 1200-baud AFSK/FM -- and NO FEC -- you'd get an > overall raw data rate of 1200 bits per second *IF IT DECODES*. MT63 > (in 2 kHz rather than 15 kHz bandwidth) would do 20 symbols of 7 > bits, or 140 bits per second raw throughput. 1200 bps / 15 kHz = 80 > bps per kHz of spectrum, compared to 140 bps / 2 kHz = 70 bps per kHz > of spectrum: not significantly different for strong signals. But the > difference on weak or fading signals would be 70 vs. nothing. > > So, while packet-over-FM on 10m is certainly legal, I'll certainly > agree with you that it's still not necessarily the best idea. > > 73, > > - ps >
Re: [digitalradio] NBFM Packet & Voice on HF?
KV9U wrote: > Good points, Paul, > > One thing that I found with longer distance FM signals on HF, even > though 10 meters can be close to the MUF when it is open, is that there > is a lot of frequency inversion or other anomalies from the ionosphere > that make it rather annoying and unsatisfactory. This is not true with > narrow bandwidth modes such as SSB. If you were just using FM for local > communications it is much more satisfactory and we have found it can > compete well with 2 meter repeaters in some cases. Instead of dropping > out, the signal just gets weaker, but often still readable. Given the comment in the original posting about the older receiver supporting NBFM and therefore it must "have once been permitted", I was reading the main question as the one of legality. I haven't tried AFSK over FM on 10 meters, but given what I've heard on 10M FM during the last sunspot maximum, I would definitely agree with you that the propagation characteristics -- which are obnoxious enough on FM voice -- would probably destroy a packet signal. During the sunspot minimum, though, it might provide convenient local links, although a different modulation scheme would give better results even for that. > This is almost like the attempt to use a mode such as digital voice on > the HF bands. It needs a very good S/N ratio to stay locked in. > > Even digital SSTV/FAX modes which fit into a regular narrow voice > bandwidth will display almost continuous damage to at least some of the > tones at any one time when you observe them on the waterfall. I've watched lots of MT63 on the lower end of the HF spectrum, and observe the diagonal lines from the fading so some extent *most* of the time. With 1200-baud AFSK/FM -- and NO FEC -- you'd get an overall raw data rate of 1200 bits per second *IF IT DECODES*. MT63 (in 2 kHz rather than 15 kHz bandwidth) would do 20 symbols of 7 bits, or 140 bits per second raw throughput. 1200 bps / 15 kHz = 80 bps per kHz of spectrum, compared to 140 bps / 2 kHz = 70 bps per kHz of spectrum: not significantly different for strong signals. But the difference on weak or fading signals would be 70 vs. nothing. So, while packet-over-FM on 10m is certainly legal, I'll certainly agree with you that it's still not necessarily the best idea. 73, - ps
Re: [digitalradio] NBFM Packet & Voice on HF?
Good points, Paul, One thing that I found with longer distance FM signals on HF, even though 10 meters can be close to the MUF when it is open, is that there is a lot of frequency inversion or other anomalies from the ionosphere that make it rather annoying and unsatisfactory. This is not true with narrow bandwidth modes such as SSB. If you were just using FM for local communications it is much more satisfactory and we have found it can compete well with 2 meter repeaters in some cases. Instead of dropping out, the signal just gets weaker, but often still readable. This is almost like the attempt to use a mode such as digital voice on the HF bands. It needs a very good S/N ratio to stay locked in. Even digital SSTV/FAX modes which fit into a regular narrow voice bandwidth will display almost continuous damage to at least some of the tones at any one time when you observe them on the waterfall. 73, Rick, KV9U Paul L Schmidt, K9PS wrote: >kd4e wrote: > > >>Anyone familiar with NBFM Packet activity on 10M, >>29,100 - 29,300MHz ? >> >>I came upon an old Sonar VFX 680 NBFM/CW exciter >>that covers 160-2M and it got me wondering why >>NBFM is not included across the Ham HF spectrum >>bandplan. I don't believe it is any wider than >>an AM signal. >> >> > >It all depends on what you mean by narrow-band. > >Historically, Narrow-band FM was 5 kHz deviation rather >than the 15 kHz that was used on the old 60-kc spaced >rigs. > >More recently, they're 'narrow-banding' FM to 2.5 kHz >deviation. > >The newer definition would be legal under FCC part 97 - >the restriction which used to say 'no wider than AM' >now says > > No angle-modulated emission may have a modulation index > greater than 1 at the highest modulation frequency. > >So the 'new' definition of 'narrow-band' would fit. > >... but older equipment would be using the 'old' >definition... a roughly 15 kHz wide signal. > >Note that the restriction on bandwidth is only for >frequencies below 29.0 MHz. 5 kHz deviation *IS* >legal above 29.0. > >And, for those not in the USA -- the regs are probably >totally different. > > > >>Collins Model 75A-1 is an AM/CW/NBFM receiver from >>1946, so NBFM would appear to have once been permitted. >> >> >> > >My TS-430S also supports NBFM... and I use it on 10 >meters :) Collins may also have had in mind using it >with a VHF converter. > > > > > > > > > >
Re: [digitalradio] NBFM Packet & Voice on HF?
kd4e wrote: > Anyone familiar with NBFM Packet activity on 10M, > 29,100 - 29,300MHz ? > > I came upon an old Sonar VFX 680 NBFM/CW exciter > that covers 160-2M and it got me wondering why > NBFM is not included across the Ham HF spectrum > bandplan. I don't believe it is any wider than > an AM signal. It all depends on what you mean by narrow-band. Historically, Narrow-band FM was 5 kHz deviation rather than the 15 kHz that was used on the old 60-kc spaced rigs. More recently, they're 'narrow-banding' FM to 2.5 kHz deviation. The newer definition would be legal under FCC part 97 - the restriction which used to say 'no wider than AM' now says No angle-modulated emission may have a modulation index greater than 1 at the highest modulation frequency. So the 'new' definition of 'narrow-band' would fit. ... but older equipment would be using the 'old' definition... a roughly 15 kHz wide signal. Note that the restriction on bandwidth is only for frequencies below 29.0 MHz. 5 kHz deviation *IS* legal above 29.0. And, for those not in the USA -- the regs are probably totally different. > Collins Model 75A-1 is an AM/CW/NBFM receiver from > 1946, so NBFM would appear to have once been permitted. > My TS-430S also supports NBFM... and I use it on 10 meters :) Collins may also have had in mind using it with a VHF converter.
