What is this 300 symbol/sec limit? I don't see that in Part 97.
§97.305(c) of this Part.
(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.
(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.
You will note that the description the maximum frequency shift that it
references a single carrier. Thus the reference to the symbol rate is for one
carrier.
In the Frederick/Harris modem, as I recall, no "carrier tone" has a symbol rate
of more than 45.5 (baud). Therefore Ok under Part 97.
In interpreting Federal Administrative Code or Law, unless a prohibition is
specifically stated, you should not take it as implied.
There is no implication that the 300 rate limit is for the total sum of all
carriers (tones) in a mode, rather for a single tone or carrier.
I am not an attorney but have a number of years working with government
engineers and DoD and DoJ attorneys in interpretation of Federal Administrative
Code or Law.
If the FCC wants to limit the symbol rate to 300 for the total sum on all data
in a mode, then they are obligated to say so. The public must NOT be left to
guess what the "agency" is trying to say. Our laws MUST BE CLEAR and
understandable. Administrative Law and Code does not, nor was it meant to
convey our national feelings, prides or desires. Rather to specifically define
limits and give direction in the implementation of Public Law.
Don't put words in the FCC's code.
And, don't let MARS interpretation of Part 97 cloud you view of it.
73,
Walt/K5YFW
-----Original Message-----
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Wednesday, August 30, 2006 2:06 PM
To: digitalradio@yahoogroups.com
Subject: RE: [digitalradio] Re: ALE QRM is minimal
Hi Walt,
I guess you mean the Frederick 1102 made under license from Harris?
I have one of those actually. They are strictly to the standard,
1800hz PSK carrier, 2400bps symbol rate, the needed channel BW is
300-3300hz (3Khz) at any supported data rate (75-2400bps coded). Its
that symbol rate, its to high, it exceeds the 300 symbol/sec limit
per FCC Part 97.
In MARS-ALE I added tailoring to get down to a 1200hz PSK carrier and
1600bps symbol rate, it works great at 200-2200hz for a 2Khz BW, but
the symbol rate is still to high.
/s/ Steve, N2CKH
At 02:47 PM 8/30/2006, you wrote:
>Steve,
>
>Why wouldn't the MIL-STD-118-110x (FS-1052) and high speed serial
>tone modes not be legal under Part 97?
>
>There used to be a bunch of hams on the East Coast who ran the
>Fredericks(sp) version of the Harris Serial Tone Modem on HF and at
>least one was an FCC engineer. One of the groups was even selling
>the Fredericks modem for under $1000. They didn't have an special
>license or permission from the FCC as far as I know.
>
>Walt/K5YFW
>
>
>-----Original Message-----
>From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
>Sent: Tuesday, August 29, 2006 4:33 PM
>To: digitalradio@yahoogroups.com
>Subject: Re: [digitalradio] Re: ALE QRM is minimal
>
>
>
>GA Rick, Patrick:
>
>The stuff from MIL-STD-188-141B that relates the MIL-STD-118-110x
>modem and Data Link Protocols (DLP) via other standards (e.g.
>FS-1052 DLP, S5066 DLP etc.) is all high speed serial tone and as
>specified, not legal under FCC Part 97 at present in the U.S., I do
>not know all the rules OCONUS. MIL-STD-188-110x with an added DLP is
>quite doable on the PC Sound Device Modem, I have tailored it down to
>where it is almost FCC legal, but when trying to go lower than a
>1600bps symbol rate to get there it just failed to work, the PSK
>carrier at 1200hz was as low as it could go, at that symbol rate and
>carrier combination is a 2Khz BW from 200-2200hz but almost twice the
>legal symbol rate the last I worked on it. I am hoping FCC rules
>changes will allow it in the near future as it works great from a
>150-2400bps coded data rate. The 75bps data rate uses a rake
>algorithm which is nearly unstoppable but at a full 3Khz BW.
>
>What Patrick and others could easily code on an FSK PC Sound Device
>Modem that would be legal is the optional Data Block Message (DBM)
>FEC (BRD) and ARQ protocols from MIL-STD-181-141x which is an 8FSK
>125 baud protocol, it and GTOR are kissing cousins as Kantronics
>developed GTOR with influence by the standards on which DMB is based.
>All of the details are spelled out in the standards for anyone that
>wishes to implement the protocol.
>
>Get a copy of PC-ALE and single channel just establish a link between
>you and another station and then fire off a DBM BRD or ARQ message,
>there are settings for number of retries and maximum frame size, with
>DBM supporting binary data there is also a DBM FTP selection for
>sending files. The speed is always fixed at maximum.
>
>/s/ Steve, N2CKH
>
>
>
>At 04:44 PM 8/29/2006, you wrote:
> >Hello Rick,
> >
> > >How difficult would this be to implement the MIL-STD-188-141-B DLP in
> > >software such as Patrick's Multipsk Program?
> >It depends, in general, on the precision of the specifications. If
> >you must reverse-engineers (is it English?) to extract the necessary
> >information, it's long. If all is clear, it cannot be very long
> >except if there are a lot of possible configurations and/or a
> >protocol to manage. However, for instance, I have a lot of other
> >subjects, but in the future who knows...
> >
> >73
> >Patrick
> >
> >
> > ----- Original Message -----
> > From: KV9U
> > To: digitalradio@yahoogroups.com
> > Sent: Tuesday, August 29, 2006 10:06 PM
> > Subject: Re: [digitalradio] Re: ALE QRM is minimal
> >
> >
> > OK Steve,
> >
> > I got the impression that the various modes mentioned below were a part
> > of STANAG 5066 and did not realize that there is a separate DLP part of
> > STANAG 5066. The jargon gets to be a bit much, but very common for
> > military type descriptors.
> >
> > For some reason, the data transfer part of this has not been really
> > talked about much and the focus has been more on ALE. I find the ARQ
> > mode to be the real value in all of this. Assuming it can perform
> > reasonably well.
> >
> > Tell us more about the waveform type, number of tones, and how this
> > works compared to your experiences with the typical sound card modes
> > that we normally use.
> >
> > Is this going to be available for amateur use eventually?
> >
> > How difficult would this be to implement the MIL-STD-188-141-B DLP in
> > software such as Patrick's Multipsk Program?
> >
> > 73,
> >
> > Rick, KV9U
> >
> > Steve Hajducek wrote:
> >
> > >Hi Rick,
> > >
> > >Just time for a quick comment.
> > >
> > >Don't confuse STANAG 5066 Data Link Protocol (DLP) as covered in
> > >MIL-STD-188-141B which is a Data Link Protocol at the Physical Layer
> > >with STANAG 5066 which is a network protocol at the Link Layer.
> > >Basically and DLP with the need ARQ support and speed can be used at
> > >the Physical Layer. If an MT-63 Adaptive ARQ protocol with a
> > >transport layer and enough speed were to develop it could be used.
> > >
> > >STANAG 5066 DLP (S5066) replaced FED-STD-1052 DLP (FS-1052) going
> > >from MIL-STD-188-141A to MIL-STD-188-141B. Both are DLP's that make
> > >use of the MIL-STD-188-110x modems, both provide and ARQ protocol,
> > >where 5066 DLP is much improved.
> > >
> > >We use FS-1052 daily in MARS, we get full 2400bps throughput on a
> > >good channel with stations that are properly configured. We have not
> > >yet implemented S5066, its on the "To Do" list.
> > >
> > >/s/ Steve, N2CKH/AAR2EY
> > >
> > >At 11:16 AM 8/28/2006, you wrote:
> > >
> > >
> > >>One of the main interests that I have in digital modes is getting a
> > >>message through the most difficult conditions, completely intact as
> > >>sent, and as fast as possible. I was looking at the STANAG 5066
> > >>specifications and test results, (Steve has some below), and quite
> > >>frankly I am concerned that this standard has what I would normally
> > >>consider to be unacceptable performance (non performance) with weak
> > >>signals.
> > >>
> > >>I am not sure what kind of cps or wpm throughput the bit rates mean but
> > >>it I wonder how it compares to SCAMP running at 10 db S/N? Because
> > >>SCAMP only operated down to about +10 db S/N (maybe slightly
> better), it
> > >>was rejected as unacceptable for practical messaging.
> > >>
> > >> From the info on Steve's site:
> > >>
> > >>http://www.n2ckh.com/MARS_ALE_FORUM/MIL-STD-188-110B.pdf
> > >>
> > >>Here are some claimed performance levels:
> > >>
> > >>Bit rate Multipath SNR BER
> > >>
> > >>4800 2 ms 27 db 1 x e-3 with .5 Hz
> > >>fading BW
> > >>2400 2 ms 30 db 1 x e-3 with 5 Hz
> > >>fading BW
> > >>1200 2 ms 11 db 1 x e-5 with 1 Hz
> > >>fading BW
> > >>300 5 ms 7 db 1 x e-5 with 5 Hz
> > >>fading BW
> > >>75 5 ms 2 db 1 x e-5 with 5
> > >>Hz fading BW
> > >>
> > >>Even with the slowest 75 bps, and a multipath of 5 ms, it can only work
> > >>down to 2 db ABOVE the noise! This is not good. From personal
> > >>experience, it is not easy to get even 10 db S/N signals with typical
> > >>amateur signals with modest antennas on the lower bands.
> > >>
> > >>They even show some constellations at 64 QAM. From what the SSTV folks
> > >>have said, 64 QAM is not really a useful mode on HF. Perhaps that is
> > >>because they are not using ARQ?
> > >>
> > >>Note also that the multipaths are moderate to low compared to
> worst case
> > >>HF propagation. I question whether this stuff can work under many
> > >>conditions we routinely operate with sound card modes (but are not 100%
> > >>copy without ARQ).
> > >>
> > >>The BER that this system can handle seems to indicate that the channel
> > >>has to be rather good. These BER's seem to be more appropriate for what
> > >>we would expect on equipment designed for VHF and up ... aren't they?
> > >>
> > >>For those of you who have used STANAG 5066 waveforms, what kind of
> > >>throughput have you experienced with real world connections?
> > >>
> > >>The deeper I examine this NATO standardized agreeement, the more it is
> > >>beginning to look like another one of those "the emperor has
> no clothes"
> > >>findings.
> > >>
> > >>Thanks and 73,
> > >>
> > >>Rick, KV9U
> > >>
> > >>
> > >>
> > >>
> >
> >
> >
> >
> >
> >[Non-text portions of this message have been removed]
> >
> >
> >
> >Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
> >
> >Other areas of interest:
> >
> >The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/
> >DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy
> discussion)
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
>
>
>
>
>Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
>
>Other areas of interest:
>
>The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/
>DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion)
>
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
>
>Other areas of interest:
>
>The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/
>DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion)
>
>
>Yahoo! Groups Links
>
>
>
>
Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
Other areas of interest:
The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/
DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion)
Yahoo! Groups Links
Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org
Other areas of interest:
The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/
DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion)
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