Packet rates HF/VHF/UHF under part-97


Graham
 

Q what  are the  maximum  packet rates  ?

HF  300 baud packet  , limited by the  max  300  baud  rule  ?  
if  using  other  modulation system,  then over  300 baud is  possible ,  eg winlink  etc ?

Is there  max  baud  rate  for  vhf   , norm   is  1200  for   2  meters  and  9600  for  70  cm  
of just  max  b/w  of  signal ?

Tnx-G,


Rick Muething
 

Graham,

It is important to separate and understand terms:

Modulation type: Common types are: Frequency shift keying FSK, sometimes called nFSK, 4FSK, 8FSK etc) Phase shift keying (PSK, BPSK, 4PSK, 8PSK etc.)   Quadrature amplitude modulation( QAM combination of Phase and amplitude  e.g  32QAM etc )  and a few other less common ones (Chirp etc) . 

A protocol (e.g. Pactor, WINMOR, Robust Packet, ARDOP etc) uses one or more of the above modulation schemes with a complex and detailed set of protocol rules to allow data transmission (FEC or ARQ) and synchronization. Each protocol will have a detailed public document that tells how it works.

The 300 baud limitation (US)  currently applies to all amateur frequencies under 29.0 MHz  It says basically that the max symbol rate (1 symbol per second is 1 baud) on ANY carrier is 300 symbols per second (or 300 baud). [note a symbol may contain 1 or more bits...e.g. one symbol of 8PSK modulation represents 3 bits) ]. Many protocols (Pactor, WINMOR, ARDOP etc) use 2 or more simultaneous carriers and this is usually referred to as OFDM (Orthogonal Frequency Division Multiplex,  which allows multiple simultaneous and closely spaced carriers to not interfere with each other).  In practice symbol rates above 300 aren't too practical on HF because of multipath distortion. Pactor 4 with its mechanism for channel compensation is an exception and has some modes over 300 baud.

There is no "Winlink protocol"  (Winlink is a communication network and currently supports the following HF protocols: Pactor 1-4, WINMOR, ARDOP (using BPQ), Robust Packet (300 baud HF packet).  There has been some experimentation with VARA (a new low baud high number of carriers 2.4 KHz mode).

Different rules apply above 29 MHz and VHF/UHF.

73, 

Rick Muething KN6KB  Winlink Development Team, Developer of WINMOR and ARDOP.




On 10/7/2017 12:28 PM, Graham wrote:
Q what  are the  maximum  packet rates  ?

HF  300 baud packet  , limited by the  max  300  baud  rule  ?  
if  using  other  modulation system,  then over  300 baud is  possible ,  eg winlink  etc ?

Is there  max  baud  rate  for  vhf   , norm   is  1200  for   2  meters  and  9600  for  70  cm  
of just  max  b/w  of  signal ?

Tnx-G,


Graham
 

Yes thank's  Rick 

The concern was, is packet defined by  ''name'' with in the  part-97 , similar as  spread spectrum  
is defined by name  alone ?

Its  reasonable to link  the  300  bauds used  by  packet   on HF , with the  300 baud  carrier  rate limit  ?

but   in the  case of  more elegant systems ,  ie   [winlink] ,should  read  winmore,  then 
the  system  data  rate  exceeds the  single carrier  limit 

So , packet  at say,  1200  bauds in 2.4 KHz  ssb channel  ,  using  ,  ofdm  would be  acceptable   over a  HF link 

similarity  , its  reasonable to   assume, that there  is  no  specified  maximum  rate  for  either  carrier or  'packet' 
above  29 MHz ,

Bandwidth alone may be the  limitation , or  are there specific entries in the  part-97 above 29  MHz  ?


Thank's 

Graham
G0NBD





M5AKA
 

Graham wrote "So , packet  at say,  1200  bauds in 2.4 KHz  ssb channel  ,  using  ,  ofdm  would be  acceptable   over a  HF link"

No, 1200 baud is not permitted in USA on frequencies below 28 MHz, the maximum allowed is 300 Baud but I think in your question you may be confusing Baud and Bits per second?
1200 bits per second or higher is permitted below 28 MHz as long as the Symbol Rate doesn't exceed 300 Baud.

On 6m and 2m maximum Symbol Rate is 19.6 kilobaud and bandwidth 20 kHz.

On 222 MHz and 70cm maximum Symbol Rate is 56 kilobaud and maximum bandwidth 100 kHz.

I beleive there is only one brief reference to the word "packet" in Part 97, it's mentioned in passing in § 97.303 (l) In the 219–220 MHz segment:
(1) Use is restricted to amateur stations participating as forwarding stations in fixed point-to-point digital message forwarding systems, including intercity packet backbone networks. It is not available for other purposes.

73 Trevor M5AKA


On Saturday, 7 October 2017, 21:16, Graham <g0nbd@...> wrote:


Yes thank's  Rick 

The concern was, is packet defined by  ''name'' with in the  part-97 , similar as  spread spectrum  
is defined by name  alone ?

Its  reasonable to link  the  300  bauds used  by  packet   on HF , with the  300 baud  carrier  rate limit  ?

but   in the  case of  more elegant systems ,  ie   [winlink] ,should  read  winmore,  then 
the  system  data  rate  exceeds the  single carrier  limit 

So , packet  at say,  1200  bauds in 2.4 KHz  ssb channel  ,  using  ,  ofdm  would be  acceptable   over a  HF link 

similarity  , its  reasonable to   assume, that there  is  no  specified  maximum  rate  for  either  carrier or  'packet' 
above  29 MHz ,

Bandwidth alone may be the  limitation , or  are there specific entries in the  part-97 above 29  MHz  ?


Thank's 

Graham
G0NBD







Graham
 

Ok Trevor 

I was  using  baud in the  context of   channel  transfer rate , hence the  2.4k  and ofdm  qualifier 

But, by what ever means ... that's the  information I was looking  for  !

Tnx-G, 


M5AKA
 

Graham, Just run across this useful summary of US Regs regarding Digital Modes




73 Trevor M5AKA





Graham
 

Hi Trevor ,

It's  Lucky  that's a  clarification of the  regulations ,  one could be  slightly confused  by a  more  in-depth version .

At the  moment , the  packet fact finding , has been confounded , by  available  ''rig design''  its  apparent,  that access  to  9600 baud , eg on 70 cm , entails  the  engagement of a  'fixed'  modulation system, it not  being  possible to change the  modulation , as  in the , more  normal
audio via ssb .   Rx via  sdr  is  simple, but the complimentary Tx is still  proving illusive ..

73-G,


M5AKA
 

Yes existing VHF/UHF rigs lock you into one modulation type for 9600 bps. Maybe in coming years we'll see some fully programmable SDR transceivers for those bands.

Also on the horizon will be the FCC looking at Part 97 Regs. Given that the FCC considered the Regs out-of-date and wanted to completely rewrite them back in 1977 (Docket 20777), but was stopped by amateur protests, it's a safe bet that 40 years later the new FCC administration will also consider them in need of a major overhaul.

This year's modernization of Part 95 Regs (GMRS, FRS, CB) shows which way they are likely to proceed - Deregulation - scrapping of unnecessary rules.

73 Trevor M5AKA


On Wednesday, 18 October 2017, 23:24, Graham <g0nbd@...> wrote:


Hi Trevor ,

It's  Lucky  that's a  clarification of the  regulations ,  one could be  slightly confused  by a  more  in-depth version .

At the  moment , the  packet fact finding , has been confounded , by  available  ''rig design''  its  apparent,  that access  to  9600 baud , eg on 70 cm , entails  the  engagement of a  'fixed'  modulation system, it not  being  possible to change the  modulation , as  in the , more  normal
audio via ssb .   Rx via  sdr  is  simple, but the complimentary Tx is still  proving illusive ..

73-G,



Graham
 

I spotted your post a  while ago Trevor, but  looking  around since, its difficult to concur , not that it's a  laudable  concept , where  it not  for the  time  and  effort that  has been  expended, in what  Mr T referees to as 'fake news'  concerning the  architecture and design of data modes , to  comply  with the  part-97 , the  wiki  page history   for  olivia is a prime  example , to the  point of demeaning the  ability of the  designer. 

In the  link you provided, there is even a  physical  'cw' test  to judge compliance, taking the  FCC responds to petitions and the  arrl directors,  now,  apparently being  under  'new management' ,with 'the' main issue's  , erased and  re-modelled , rather  in the  style of 'the history of  post revolution Russia' ,   its  difficult to imagine a situation , where an  elegant solution  is to be  reached ?

Who is to raise petition's  about subject's that  are none existent  in the  psyche  of the  users  ?

73-G,



M5AKA
 

That CW / Process Gain test for Part-15 products seems like a joke now but it was symptomatic of the excessive regulation that the FCC used to indulge in.

Fortunately the FCC under Ajit Pai is now determined to modernize the rules for all Services. They've got a lot of work ahead of them and regrettably Amateur Radio isn't at the front of the line but I'm sure they'll eventually get round to sorting out Part 97.

To this day many hams are unable to comprehend the difference between the FCC terms “Spread Spectrum” and “SS”.

Even people at ARRL HQ can have difficulty interpreting Part 97. At the end of the last century the League was convinced wideband multiple carrier HF data modes weren’t permitted. It took them some time to realise Part 97 did in fact permit data signals which could in theory occupy an entire band.

Hopefully FCC will soon action the ARRL Symbol Rate petition before they carry out the major task of reforming Part 97.

73 Trevor M5AKA

On Thursday, 2 November 2017, 20:47, Graham <g0nbd@hotmail.com> wrote:


I spotted your post a  while ago Trevor, but  looking  around since, its difficult to concur , not that it's a  laudable  concept , where  it not  for the  time  and  effort that  has been  expended, in what  Mr T referees to as 'fake news'  concerning the  architecture and design of data modes , to  comply  with the  part-97 , the  wiki  page history   for  olivia is a prime  example , to the  point of demeaning the  ability of the  designer. 

In the  link you provided, there is even a  physical  'cw' test  to judge compliance, taking the  FCC responds to petitions and the  arrl directors,  now,  apparently being  under  'new management' ,with 'the' main issue's  , erased and  re-modelled , rather  in the  style of 'the history of  post revolution Russia' ,   its  difficult to imagine a situation , where an  elegant solution  is to be  reached ?

Who is to raise petition's  about subject's that  are none existent  in the  psyche  of the  users  ?

73-G,