|
Would anyone care to play with OFDM in the afternoon and/or evening hours, say on 80m, 40m, 30m, or ???.
Best regards,
Gary, K7EK
|
|
|
I just kept pressing the LK button on/off many times
It is going to be "repaired'
On Mar 5, 2021, at 3:16 PM, Frank Olaughlin < wq1o.frank@...> wrote: Barry,
How did you move the center frequency on OFDM-2000F? When I change it, it moves in the box, but the actual frequency doesn't change. Same if I adjust it in the WF.
73
Frank
WQ1O
|
|
|
Frank Olaughlin
Ron,
Good observation! Thanks.....that works.
Looking forward to the new updates.
73
Frank
WQ1O
|
|
|
Re: interesting test today on 440 FM repeater
Hi Barry,
The OFDM 500F, 750F, and 2000F modes should work over repeaters also. Not certain if they will provide much more robustness, as line-of-sight-FM is already a very clean signal. OFDM-2000F may work through multiple-linked repeater systems a bit better, but that would need to be tested.
OFDM-2000F and OFDM-2000 were designed to Just-Barely fit into a normal HF-SSB channel. These modes were at the request of NBEMS-Hawaii mailing-list discussions, wanting a fast-as-you-can mode for HF line-of-sight (island to island)
The only way to get 2000 or 3000 bits/second over HF SSB with OFDM-2000/2000F was to really push the bandwidth-limits to their max. This required locking the Tx frequency though to prevent signal-cutoff. Rx is still frequency agile to compensate for radio frequency offsets.
So, this is why OFDM-2000F and 2000 are transmit-center-frequency locked to 1325Hz. Adjusting even 10Hz either direction would cut-off portions of the signal. At 2Khz of bandwidth, it is at the very-limit of what stock HF-filters allow (and a bit too wide for 1.8Khz filters).
As far as using OFDM-2000F vs the 8PSK modes... it depends on the repeater system. When using faster-baud rate single carrier modems, there is a bit more robustness to phase-distortions than slower baudrates. The faster the baudrate, the wider the signal-bandwidth, spreading-out the phase distortions and allowing decode. The drawback though is faster baudrates need a higher signal-to-noise ratio to operate (less sensitivity).
Using a slower-baudrate multi-carrier mode like OFDM-2000F will work when there is less signal strength (more sensitive), but at the cost of being far less tolerant of phase-distortions. For HF we know the signal is most-likely going to be kinda quiet, and SSB-radios are very phase-stable, so multiple slower carriers win-out as the best solution.
The OFDM modes do spread the bits over multiple carriers, so if 1 carrier is cutoff by filtering or distortions, decode should still be 100% This also nicely keeps us far-under the FCC baudrate limits for HF, while still allowing good datarates.
Thank you for all the testing, John Phelps KL4YFD
John KL4YFD
Updates....
Is there any reason why the OFDM500F and OFDM750F should
not work on a standard FM analog voice repeater?
Afer all, it is just 'sound'.
We just tried OFDM500F and it sent a FLAMP flawlessly on a 440
FM voice repeater (linked to two other 440 machines).
So the OFDM500F and 750F are narrow enough for a typical SSB
frequency (and filter) but I think should work fine on FM radios.
What if we were to try the OFDM2000F on 80m SSB?
Obviously we'd need 2 kHz bandwidth (on 80m in the morning,
that's not a problem for a quick test).
I noticed the 2000F wanted to "center" at 1325 Hz on
waterfall. Why?
We generally center all modes at 1500 Hz on SSB and on FM.
Any reason why we should not center 2000F mode at 1500 Hz on a
FM voice repeater?
I modified my (old) SignaLink to use the 9600 baud Rx audio, and
changed my Icom 706MIIG to the MENU 9600 baud option,
and then modified the SignaLink to get a bit more Tx audio and
everything works FINE on FM setting on the Icom 706.
Just exchanged some FLAMP using OFDM2000F both centered at
1325 and 1500.
We even tried centering OFDM2000F at 2000 Hz on WF, and it
worked as well.
It sounds awful (like VARA) but it works!
So OFDM2000F is 8 "carriers" or sub-carriers, and each has
a lower baud than the high values of single carrier 8PSK1000F.
My guess: OFDM2000F is going to work better than 8PSK1200F on
our typical radios and FM repeaters ....
it spreads the information over 8 "carriers" (lower baud
each) like having 8 wires carrying information vs. one wire.
Am I correct?
So far, this has been fascinating.
Oh... and NY3J and N3FLL both have the RMA-70 new wide freq
modems. I'm jealous.
I'm still stuck with the old SignaLink, but maybe I'll break down
and buy a RMA modem.
I see the 'new' SignalInks have better wider audio transformers
and better chips (line input vs. mic input).
TU
Barry k3eui
|
|
|
Frank,
Try this. After you move center frequency turn on LK then off again
and it looks like it frees it up. It looks like Dave is working on a
few things and an update is in the works.
73, Ron NY3J
toggle quoted messageShow quoted text
On 3/5/21 3:16 PM, Frank Olaughlin
wrote:
Barry,
How did you move the center frequency on OFDM-2000F? When I
change it, it moves in the box, but the actual frequency doesn't
change. Same if I adjust it in the WF.
73
Frank
WQ1O
|
|
|
Dave
at
http://www.w1hkj.com/alpha/fldigi/
Contains fixes to OFDM
bugs reported for version 4.1.18.15. Be sure that both Tx and
Rx are using the same version for RsID to work corrrectly.
73, David, W1HKJ
Fri Mar 5 14:20:00 2021 -0600 -
alpha 4.1.18.16
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps
<kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the
9600-jack
PSK-modes fix false triggers of DCD-OFF - Author: John Phelps
<kl4yfd@...>
* Certian character combinations were triggering DCD-OFF
* DCD-OFF code now searches over 6-bit window
* Prevents rare data-loss bug mid-transmission
|
|
|
Frank Olaughlin
Barry,
How did you move the center frequency on OFDM-2000F? When I change it, it moves in the box, but the actual frequency doesn't change. Same if I adjust it in the WF.
73
Frank
WQ1O
|
|
|
Re: [linuxham] fldigi 4.1.18.15 alpha posted
Hi Joe,
For the OFDM FEC-enabled modems, the RSID is a part of the modem, and not a separate option that can be turned-off. This is simply a requirement when using 4PSK or 8PSK modulations due to the frequency-accuracy requirement and FEC design.
The RSID's have been coded into the OFDM "F" modes as the header which both sets frequency (AFC) and flushes-out any previously received noise-bits. Due to the long multi-second interleaver and the heavy FEC, it is basically required to have this flush pre-data-start. Without such a flush, noise-bits from 4-6 seconds previously will mix-into the FEC and degrade the decode.
This "use the RSID as modem-header" setup was coded into Fldigi many years ago by John Douyere, VK2ETA and others when multi-carrier capability was first-added. Was kind of the plan for about 6 years now to use the RSID and an AFC-solution when going multi-carrier.
"RSID as the modem-header" has ended up being a rather slick solution that works even via Web SDR's and old Boat-Anchor HF radios, both of which are notoriously off-frequency and sometimes a bit drifty.
73's John Phelps KL4YFD
On Fri, Mar 5, 2021 at 9:21 AM Joseph Counsil, KØOG < counsil@...> wrote:
Dave,
The OFDM modem is a nice addition -- Thanks to John for working
on development of that!
I find between my two stations (one running on Win10x64, the
other on Linux Mint 20.1) that the RSID can not be disabled when
an OFDM modem is selected, and sometimes the receiving station
grossly misidentifies the OFDM mode, so I miss a transmission.
This is with good signal strengths between the two stations. I
think the RSID needs to be looked at to improve RSID
encode/decode performance, and it would be good to be able to
control TXID/RXID with the Fldigi buttons (they exert no control
on the OFDM modems). When both stations do get on the same
mode, they seem to work fine, but I need to do more testing with
weak signals.
73,
-Joe-
w1hkj wrote:
at http://www.w1hkj.com/alpha/fldigi/
Apple dmgs are signed, but not
certified by Apple.
. *bs.dmg - universal Intel/M1 cpu for Big Sur 11.x
. *hs.dmg - Intel x86_64 build on High Sierra 10.13.6
. *lion.dmg - Intel x86_64 build on Lion 10.7.6
Fri Mar 5 06:30:00 2021 -0600 - alpha 4.1.18.15
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps <kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the
9600-jack
PSK-modes fix false triggers of DCD-OFF - Author: John
Phelps <kl4yfd@...>
* Certian character combinations were triggering DCD-OFF
* DCD-OFF code now searches over 6-bit window
* Prevents rare data-loss bug mid-transmission
fmt
* add callback handlers to
. btn_unk_enable
. btn_ref_enable
. btn_fmt_record
* reset frequency whenever ref or unk button is pressed
Win32 Serial Port
* change
"if (!hComm)" to
"if (hComm == INVALID_HANDLE)"
CW punctuation
* Allow user to suppress decode/encode of specific
punctuation characters
* Allow user to select character to display noise decodes
. default '*'
. '_'
. ' '
. none
WX
* Correct <WX:xxx> weather macro text substitution
Canada
* Add missing provinces / regions
PulseAudio Server String
* always enable PA server string control to allow user
to clear or modify entry
* fix hanging up on server fault message dialog
. caused by message dialog on being re-entrant
macOS arm64 builds
* Change macosx macro to include darwin20 target
Waterfall buttons
* Set all buttons to visibile for new installation
Audio Codec
* fix for Portaudio h/w codec missing during fldigi
startup
. missing h/w could cause segmentation fault on some
systems
. added try{}catch{} to trx audio path
. display error message
. reset audio device to NULL codec
Version 4.1.18
--
Joseph A. Counsil
1310 Woodlawn Drive
Rolla, MO 65401
|
(573) 341-5186
Amateur Radio: KØOG
|
|
|
|
|
Re: fldigi 4.1.18.15 alpha posted
Joseph Counsil
Dave,
The OFDM modem is a nice addition -- Thanks to John for working
on development of that!
I find between my two stations (one running on Win10x64, the
other on Linux Mint 20.1) that the RSID can not be disabled when
an OFDM modem is selected, and sometimes the receiving station
grossly misidentifies the OFDM mode, so I miss a transmission.
This is with good signal strengths between the two stations. I
think the RSID needs to be looked at to improve RSID
encode/decode performance, and it would be good to be able to
control TXID/RXID with the Fldigi buttons (they exert no control
on the OFDM modems). When both stations do get on the same
mode, they seem to work fine, but I need to do more testing with
weak signals.
73,
-Joe-
w1hkj wrote:
toggle quoted messageShow quoted text
at http://www.w1hkj.com/alpha/fldigi/
Apple dmgs are signed, but not
certified by Apple.
. *bs.dmg - universal Intel/M1 cpu for Big Sur 11.x
. *hs.dmg - Intel x86_64 build on High Sierra 10.13.6
. *lion.dmg - Intel x86_64 build on Lion 10.7.6
Fri Mar 5 06:30:00 2021 -0600 - alpha 4.1.18.15
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps <kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the
9600-jack
PSK-modes fix false triggers of DCD-OFF - Author: John
Phelps <kl4yfd@...>
* Certian character combinations were triggering DCD-OFF
* DCD-OFF code now searches over 6-bit window
* Prevents rare data-loss bug mid-transmission
fmt
* add callback handlers to
. btn_unk_enable
. btn_ref_enable
. btn_fmt_record
* reset frequency whenever ref or unk button is pressed
Win32 Serial Port
* change
"if (!hComm)" to
"if (hComm == INVALID_HANDLE)"
CW punctuation
* Allow user to suppress decode/encode of specific
punctuation characters
* Allow user to select character to display noise decodes
. default '*'
. '_'
. ' '
. none
WX
* Correct <WX:xxx> weather macro text substitution
Canada
* Add missing provinces / regions
PulseAudio Server String
* always enable PA server string control to allow user
to clear or modify entry
* fix hanging up on server fault message dialog
. caused by message dialog on being re-entrant
macOS arm64 builds
* Change macosx macro to include darwin20 target
Waterfall buttons
* Set all buttons to visibile for new installation
Audio Codec
* fix for Portaudio h/w codec missing during fldigi
startup
. missing h/w could cause segmentation fault on some
systems
. added try{}catch{} to trx audio path
. display error message
. reset audio device to NULL codec
Version 4.1.18
--
Joseph A. Counsil
1310 Woodlawn Drive
Rolla, MO 65401
|
(573) 341-5186
Amateur Radio: KØOG
|
|
|
|
|
Re: new alpha FLDIGI available for testing new OFDM modes
Dave,
I was doing local testing between two machines with 4.1.18.15. It
looks like you have to deselect the OFDM modes in the RsID
configuration or it will send out the TxID. Also, when you change to
OFDM it changes you to 217 Hz on the waterfall.
73, Ron NY3J
toggle quoted messageShow quoted text
On 3/5/21 11:55 AM, Dave wrote:
Early testing of the OFDM
modes in 4.1.18.15 has discovered some critical issues. I
will try to have these fixed before your Sunday net.
David
On 3/5/21 8:39 AM, K3EUI Barry wrote:
***** QST *****
If you would like to help test the new "alpha" OFDM modes (HF
SSB and FM) then please download the latest ALPHA (test)
version of FLDIGI 4.1.18.15
and read all about these new changes.
The PaNBEMS net this Sunday (3583.0 kHz at 0730 hr) will test
the new mode OFDM500F with a sample FLMSG and a FLAMP (open
FLAMP on your own after FLDIGI boots)
As you will see, this new mode has a very very long delay
(interleaver) of about 8 seconds to deal with the long deep
fades common on NVIS 80m paths.
TU to KL4YFD John for helping create these new OFDM modes.
de k3eui Barry
=========================================
at http://www.w1hkj.com/alpha/fldigi/
Apple
dmgs are signed, but not certified by Apple.
. *bs.dmg - universal Intel/M1 cpu for Big Sur 11.x
. *hs.dmg - Intel x86_64 build on High Sierra 10.13.6
. *lion.dmg - Intel x86_64 build on Lion 10.7.6
Fri Mar 5 06:30:00 2021 -0600 - alpha 4.1.18.15
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps <kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the
9600-jack
|
|
|
Re: new alpha FLDIGI available for testing new OFDM modes
Dave
Early testing of the OFDM
modes in 4.1.18.15 has discovered some critical issues. I will
try to have these fixed before your Sunday net.
David
toggle quoted messageShow quoted text
On 3/5/21 8:39 AM, K3EUI Barry wrote:
***** QST *****
If you would like to help test the new "alpha" OFDM modes (HF
SSB and FM) then please download the latest ALPHA (test)
version of FLDIGI 4.1.18.15
and read all about these new changes.
The PaNBEMS net this Sunday (3583.0 kHz at 0730 hr) will test
the new mode OFDM500F with a sample FLMSG and a FLAMP (open
FLAMP on your own after FLDIGI boots)
As you will see, this new mode has a very very long delay
(interleaver) of about 8 seconds to deal with the long deep fades
common on NVIS 80m paths.
TU to KL4YFD John for helping create these new OFDM modes.
de k3eui Barry
=========================================
at http://www.w1hkj.com/alpha/fldigi/
Apple
dmgs are signed, but not certified by Apple.
. *bs.dmg - universal Intel/M1 cpu for Big Sur 11.x
. *hs.dmg - Intel x86_64 build on High Sierra 10.13.6
. *lion.dmg - Intel x86_64 build on Lion 10.7.6
Fri Mar 5 06:30:00 2021 -0600 - alpha 4.1.18.15
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps <kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the
9600-jack
|
|
|
new alpha FLDIGI available for testing new OFDM modes
K3EUI Barry
***** QST ***** If you would like to help test the new "alpha" OFDM modes (HF SSB and FM) then please download the latest ALPHA (test) version of FLDIGI 4.1.18.15 and read all about these new changes. The PaNBEMS net this Sunday (3583.0 kHz at 0730 hr) will test the new mode OFDM500F with a sample FLMSG and a FLAMP (open FLAMP on your own after FLDIGI boots) As you will see, this new mode has a very very long delay (interleaver) of about 8 seconds to deal with the long deep fades common on NVIS 80m paths. TU to KL4YFD John for helping create these new OFDM modes. de k3eui Barry ========================================= at http://www.w1hkj.com/alpha/fldigi/
Apple dmgs are signed, but not certified by Apple.
. *bs.dmg - universal Intel/M1 cpu for Big Sur 11.x
. *hs.dmg - Intel x86_64 build on High Sierra 10.13.6
. *lion.dmg - Intel x86_64 build on Lion 10.7.6
Fri Mar 5 06:30:00 2021 -0600 - alpha 4.1.18.15
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps <kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the 9600-jack
|
|
|
fldigi 4.1.18.15 alpha posted
Dave
at
http://www.w1hkj.com/alpha/fldigi/
Apple dmgs are signed, but not
certified by Apple.
. *bs.dmg - universal Intel/M1 cpu for Big Sur 11.x
. *hs.dmg - Intel x86_64 build on High Sierra 10.13.6
. *lion.dmg - Intel x86_64 build on Lion 10.7.6
Fri Mar 5 06:30:00 2021 -0600 - alpha 4.1.18.15
WF-only mode menu
* add missing modes
Add OFDM modes for NBEMS - Author: John Phelps
<kl4yfd@...>
* OFDM-500F for HF SSB
- survives HF NVIS/long path
- 4-carriers of 62.5-baud 4PSK = 250 bps
- 1/2 rate K=15 FEC with 4sec interleaver
* OFDM-750F for HF SSB
- survives HF NVIS/long path
- 3-carriers of 125-baud 8PSK = 562 bps
- 1/2 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000F for HF-SSB/FM
- 8 carriers of 125-baud 8PSK = 2000bps
- 2/3 rate K=13 FEC with 3.2sec interleaver
* OFDM-2000 for HF-SSB/FM
- 4 carriers of 250-baud 8PSK = 3000bps
- NO FEC, meant for line-of-sight
* OFDM-3500 for FM 9600-port
- 7 carriers of 250-baud 8PSK = 5250bps
- NO FEC, meant for line-of-sight
- Requires Signalink made-after 2018 connected to the
9600-jack
PSK-modes fix false triggers of DCD-OFF - Author: John Phelps
<kl4yfd@...>
* Certian character combinations were triggering DCD-OFF
* DCD-OFF code now searches over 6-bit window
* Prevents rare data-loss bug mid-transmission
fmt
* add callback handlers to
. btn_unk_enable
. btn_ref_enable
. btn_fmt_record
* reset frequency whenever ref or unk button is pressed
Win32 Serial Port
* change
"if (!hComm)" to
"if (hComm == INVALID_HANDLE)"
CW punctuation
* Allow user to suppress decode/encode of specific
punctuation characters
* Allow user to select character to display noise decodes
. default '*'
. '_'
. ' '
. none
WX
* Correct <WX:xxx> weather macro text substitution
Canada
* Add missing provinces / regions
PulseAudio Server String
* always enable PA server string control to allow user
to clear or modify entry
* fix hanging up on server fault message dialog
. caused by message dialog on being re-entrant
macOS arm64 builds
* Change macosx macro to include darwin20 target
Waterfall buttons
* Set all buttons to visibile for new installation
Audio Codec
* fix for Portaudio h/w codec missing during fldigi startup
. missing h/w could cause segmentation fault on some
systems
. added try{}catch{} to trx audio path
. display error message
. reset audio device to NULL codec
Version 4.1.18
|
|
|
K3EUI Barry
Yesterday a few of us tried using OFDM500F on a 440 FM analog repeater - it worked well.
I'm sure OFDM750F would also have worked.
OFDM2000F seems to also work well on a standard analog FM voice repeater, and we tried moving the center frequency up to 1500 Hz rather than 1325 Hz and that seemed to help. We next tried a center frequency of 2000 Hz and that worked, although listening was kind of painful.
So these new OFDMxxxF modes seem to be way faster and more rugged than other modes for high speed traffic.
We are continuing to test these also on 3583 kHz (SSB) in the early morning hours via the NH, NY, NJ, and Pa NBEMS nets on the weekends.
So far, very promising results!
TU KL4YFD
de k3eui Barry
|
|
|
K3EUI Barry
I would like to share an observation that the "available" audio on FM repeaters is 500 Hz to 3000 Hz,
or a 2500 Hz passband. I would not expect a OFDM3500 (3.5 kHz) would work, either with new of old SignaLinks.
Go lower than 500 Hz and the audio drops off, and you get close to the PL tones.
Go above 3000 Hz and I can see and hear the high frequency dropoff.
So if you are testing on FM Simplex, that's one thing, using the wider freq response 9600 baud pins.
But if you are sending audio via typical FM ANALOG repeaters, watch out.
Our experience in Chester County PA is that 8PSK1000F is just about 100% on FLMSG / FLAMP.
It is much faster than any other FLFIGI mode (but it sounds awful).
Perhaps the multi-carrier OFDM modulation will beat that a bit.
VARA FM beats every mode we've tried, but VARA is not available in FLDIGI.
And.... be absolutely certain that you have permission to test these digital sound-card based mode on a repeater.
Some repeater owners in my area say "absolutely no digital stuff".
Barry k3eui
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File transfer using FLMsg Form/Transfer
We attempted to send some files using the Transfer option under the Form menu.
We were able to send text files and a .csv file, but could not send any graphics files - jpg, png or gif.
We would use the Transmit file field and select the file to be sent, and use the AutoSend function. This worked for text files but not for the graphics files. No response.........
The FLMsg Help manual provides very little information about this option.
The illustration shows .jpg files listed in the 'Received files' list.
Can you provide more details about the functions in this window?
Thanks,
W0NRP
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Frank Olaughlin
John,
We did a two person test on OFDM3500 on Tuesday March 2nd using your latest.
Tester 1: Win 10 Laptop, FT-8900 radio, Newer Signalink, 2m VHF FM
Tester 2: Win 7 laptop, FT-8900 radio, newer signalink, 2m VHF FM
Method was Simplex with 10/9 signals
Observations:
We got about 40-50% text on simplex FM using Fldigi. It was not good enough to use Flamp. We got about 35-40% on flmsg. That was about the best we could do. Best center frequency we found to be 2250 on this version. Nothing else worked.
Version had excellent stability on Win 10, but crashed often on Win 7. The TX on the Signalink had to be at near maximum.
Thanks for all the continued hard work. I know these things are always a work in progress.
73
Frank
WQ1O
Cape Cod and Islands ARES DEC
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Re: [linuxham] What is the BW limit for US hams in DIGI bands HF
For interest
In VK we have "necessary" bandwidth of any mode defined with
operating frequency, plus a spectral density figure 80m-10m. ie it
boils down to whatever the modulation method needs, rather than
specifying a mode, Theoretically a very wide digital mode could be
used legally, but agreements/conventions/manners and local
bandplans tend to be tighter. Note that this all types of radio
emissions, not just digital.
80m-12m "Where the necessary bandwidth exceeds 8 kHz, the maximum
power spectral density from the transmitter must not exceed 1 watt
per 100 kHz.
10m "Where the necessary bandwidth exceeds 16 kHz, the maximum
power spectral density from the transmitter must not exceed 1 watt
per 100 kHz.
Generally though it is 2.1kHz below 160m, 8kHz from 160m to 12m,
16kHz on 10m, 100kHz on the bottom half of 6m and no limit from
there. Of course one must stay in band!
There is no data rate limitation. It is all bandwidth related.
Cheers Bob VK2YQA
toggle quoted messageShow quoted text
On 3/3/21 7:46 am, KL4YFD ham wrote:
Hi everyone,
Wanted to touch on the bandwidth-rules conversation again
since its coming up again,
Due to the outdated FCC rules, there is only an
HF bandwidth-limit when using FSK modulation (limit of
1300Hz)
This is the RF bandwidth of 1000Hz spacing FSK @
300-baud.
47 CFR § 97.307(f)(3)
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.
Per the current rules, there is no bandwidth limit for
PSK-based modes like OFDM, Pactor, or VARA.
Only the baudrate limitations.
That all said, having a bandplan that separates out
wide from narrow digital modes on HF would be a nice
addition for US hams.
Hope the ARRL and FCC can work together on some kind of
more-coherent set of rules.
73's
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Re: [panbems] OFDM Modes FINAL test release
K3EUI Barry
WD9EQD Bill
It looks like this was one of N3FLL's transmissions. He was using less power (40W) and a different antenna (long wire) but the signal looks good and S/N is adequate. OFDM is a multi-carrier PSK modulation. The signal in the WF looks very clean. Do you know how to turn on the FLDIGI Spectrum View (whole monitor screen)? For yesterday's tests, I was running about 200W to 300W. Barry k3eui
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Re: What is the BW limit for US hams in DIGI bands HF
Gently, I think your assertions are incorrect on both levels. This is a very complicated issue, and one of the chief goals of the amateur service is not the pleasure of the participants, but instead the advantages to the nation and its citizens that are listed in 97.1. I have grappled with a lot of these concerns and I think intense regulations are not in the best interest of the amateur radio service. people generally manage to get along and progress continues to be made in astonishing ways on many fronts.
My two cents worth
On Mar 2, 2021, at 15:47, KL4YFD ham <kl4yfd@...> wrote:
Hi everyone,
Wanted to touch on the bandwidth-rules conversation again since its coming up again,
Due to the outdated FCC rules, there is only an HF bandwidth-limit when using FSK modulation (limit of 1300Hz) This is the RF bandwidth of 1000Hz spacing FSK @ 300-baud.
47 CFR § 97.307(f)(3) 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.
Per the current rules, there is no bandwidth limit for PSK-based modes like OFDM, Pactor, or VARA. Only the baudrate limitations.
That all said, having a bandplan that separates out wide from narrow digital modes on HF would be a nice addition for US hams. Hope the ARRL and FCC can work together on some kind of more-coherent set of rules.
73's
On Tue, Mar 2, 2021 at 12:25 PM Barry Feierman < k3euibarry@...> wrote: Duane N6RVA
I will read all of this again, carefully.
But I do not agree with your conclusion (at this time). Maybe I am missing something.
At present, MANY digital stations are operating HF with a bandwidth greater than 2 kHz. Even the famous SATERN net on 20m operates with a wider BW than 2 kHz, and on 20 meters! Unattended ACDS Winlink stations are limited to 500 Hz outside the 3585-3600 kHz but we are not talking about Winlink ops.
Some history Going way back (before sound card modes) the old RTTY shift was 850 Hz, due to the lousy selectivity of receiver. So I think that MAY be where the 1 kHz "shift" maximum came from in these ancient FCC rules. The ARRL proposal of a BW limit in place of a baud limit made sense, of course, even if it was not adopted by FCC.
I even asked the guys at ARRL what the max BW of digital signals could we use for NBEMS EMCOMM nets and they said "same as SSB phone". NO one said 500 Hz or 1000 Hz.
So who is missing what? The modes we are using (sound card generated) are NOT a RTTY shift. We have no "shift" on OFDM modes of frequency.
Do you think we (NBEMS) are doing something illegal now if we use a BW of more than 1 kHz on an 80m SSB net on 3583 kHz?
I agree that the optimum BW is well under 2 kHz on a busy 80m band, But we at least know that THOR 100 and MFSK128 do work and are reliable on 80m NVIS paths.
What is your recommendation for what the NBEMS nets should do about modes? The new OFDM F modes are going to be well below 1 kHz and I like the 500F mode (make good neighbors). There is no reason to go wider than 1 kHz on 80m, unless there was a real emergency and we absolutely needed MFSK128.
So what is the bottom line?
Barry
Begin forwarded message:
Barry et al.,
In November of 2013 the ARRL requested that the FCC remove the 300
baud symbol rate and replace it with a 2.8 kHz bandwidth limitation,
the FCC agreed to removing the baud symbol rate but did not grant
the 2.8 kHz bandwidth request.
------------------------------------------------------
ARRL Renews Request for
FCC to Replace Symbol Rate with Bandwidth Limit
09/18/2019
In ex parte comments filed
on September 17 in WT Docket 16-239, ARRL renewed its request
that the FCC delete symbol-rate limits for data transmissions in
the Amateur Service rules. As it did in its initial filing, ARRL
asked the FCC to couple the removal of the symbol rate limits
with the adoption of a 2.8 kHz bandwidth limit. In response to a
2013 ARRL Petition
for Rulemaking (RM-11708), the
FCC proposed deleting the symbol-rate limits but declined to
replace them with the 2.8 kHz bandwidth that ARRL wanted.
-----------------------------------------------------
Currently, this means the maximum bandwidth for digital data can be
no greater than 1 kHz per 47 CFR § 97.307(f)(3) - Emission
standards.
In January of 2020 the ARRL proposed a new Band Plan with the
following recommended changes to the 80 meter band:
RTTY and NB data 3.500 to 3.600 MHz
RTTY, NB data and WB data 3.600 to 3.650 MHz
Narrow Data < 500 Hz
Wide Data < 2800 Hz
I have included the proposed ARRL Band Plan as attachments to this
email.
Duane
N6RVA
On 3/1/21 6:44 PM, Barry Feierman
wrote:
Hi guys
For the 80m NBEMS weekend nets,
what is the "WIDEST" bandpass we should be using to pass
traffic (drill or in a real emergency)?
If there is a BW "limit" for US hams
when operating a station on the HF bands, it is not clear (to
me) what that limit is, in Hz.
And the opinion of some of the best
digi guys at ARRL. I asked them.
Forget the baud limit (300). We are
not talking baud.
What is the BW limit for HF digi
modes below 29 MHz?
My belief is that it is essentially
the same as what KL4YDF responded:
"No wider than a phone signal" ...
or 2.8 kHz for an SSB digi mode.
I am not speaking about an auto
Winlink unattended station...... that is 500 Hz.
Here is the response I got from one
of the guys who writes the software for FLDIGI digital modes,
John KL4YFD.
I think we should all stay to a
reasonable BW unless we are in a real crisis. For me, that is
about 1 kHz. And 500 Hz seems prudent.
So when we use MFSK32 we are being
prudent.
When we jump to MFSK64 or THOR50x1
(under 1 kHz) it is only for brief testing purposes, to see if
it works faster. It does.
But I would not want to run MFSK128
on an 80m band in the morning hours.... that is asking for
trouble. MFSK128 works great on an FM 2m repeater.
Barry
On Mar 1, 2021, at 4:37 PM, John Phelps < kl4yfd@...>
wrote:
I did read an email by someone saying 500Hz is the
limit, but that is not the case for FCC rules the USA.
Possibly for European or Canadian hams though.
People use Pactor3 at 2.4Khz width routinely for
WinLink, without issue.
In addition to the 300-baud rule, we only have this
in the USA:
(2) No non-phone
emission shall exceed the bandwidth of a
communications quality phone emission
of the same modulation type
So, basically, no wider than SSB voice at about
2.7Khz.
The other rule only pertains to
fully-automated stations (unattended, on a timer).
NBEMS is control-operator-present though manually
clicking send, so does not apply.
(2) No transmission
from the automatically controlled station occupies a
bandwidth of more than 500
Hz.
So there are 500Hz bandwidth rules, but only if
unattended and fully automated.
If operator is present, and controlling, then
2.7Khz to "not be wider than phone"
John
KL4YFD
yes .. I did try some quick OFDK750F for a
minute.
No results yet. We concentrated on the 500F gear.
We could live with a 750 Hz BW data signal on busy
80m NBEMS net, but that's about the BW limit we are
comfortable using.
I have had TWO requests: where in the FCC
rules does it state a BW limit on HF ?
I can't find any BW limit, only a 300 baud limit
(useless).
But a K2 station claims there is a 1 kHz limit for
the SHIFT of a RTTY signal.
That must be going back 30+ years when I heard shifts
of 850 Hz (selectivity must have been crude back
then)
Barry
On 3/1/2021 12:28 PM, John Phelps wrote:
Hi Barry,
OFDM-500F was great decode most of the time
for me on SDR.
Thought I saw a 750F transmission for a
second, but missed pressing record in-time.
Did anyone else get a decode of the
OFDM-750F? I've only tested it here in
simulations so far.
Todays testing means I need to make the
interleaver longer in the OFDM code longer to
handle the fades.
Its about 0.5 to 1 second too short at the
moment. NVIS is a noisy-beast of a channel.
Good to hear you have about 200W going
out on 80m.
Was looking into some used RM-Italy HF amps
if they were needed for testing, but you
already have more power than that (and better
quality).
Thanks again for all the help and tests,
John
KL4YFD
Hi John KL4YFD
I just responded earlier.
We are in GREAT shape so far with OFDK500F.
Yes, my Icom 7610 and Heathkit SB220 was
about 200W.
I can run up to 700 W with that amp on
80m.
No ALC, and clean on a Tek oscilloscope
monitoring my Tx output.
The other ops were all running about 30-50 W
on TUNE, less on OFDM of course.
I think there is a SDR web in Milford Pa.
Ron NY3J has some experience with the SDR
sites since his local QTH is very noisy.
Barry
cc NY3J
On 3/1/2021 11:46 AM, John Phelps wrote:
Hi Barry,
Thank you for the testing!
I was able to receive the OFDM test
transmissions on 3580Khz using this
web-sdr:
I think at 145 miles away this puts
me out of groundwave but in
NVIS-range.
I received the FLAMP
80m_propagation.213 message
successfully.
Recordings of the session are here:
The OFDM results were mixed for me.
Sometimes great, sometimes 50%
The NVIS channel was fading about
8-10 db periodically, for a minute or
two, then recovering.
Do you have an HF amplifier?
Boosting Tx power by 8dB would
overcome most fades and only be
150watts (assuming 25watts without
amp).
The THOR and MFSK modes were
nearly-perfect copy, maybe 1-2 errors
total.
For the future OFDM tests, could
you enable Tx-RSID?
I haven't figured-out how to
auto-enable it in code... but the OFDM
modes use RSID as the header and AFC
mechanism both. There isn't actually a
modem-header/preamble without it.
73's and thank you again,
John Phelps
KL4YFD
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