[digitalradio] TV Whitespace Testing
The FCC is doing testing for the use of broadband wireless in the space between TV channels. See http://www.pcmag.com/article2/0,2704,2250638,00.asp. The challenge is kind of like BPL: preventing interference with any adjacent digital channels. From my reading, it looks like they are trying to sense when adjacent channels are in use and not use that space. This makes sense for a commercial product since it would be a challenge to get users to configure systems to avoid active channels. I wonder if we could get some channels made available for hams? Possible propose using specific whitespaces on a regional basis. The proposal would determine two open channels in an area and use the whitespace between them. For example, channels 18 and 19 here in Houston are not used so they would be an available whitespace. (I am not sure how the digital channel assignments change availability of whitespace.) Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
Re: [digitalradio] TV Whitespace Testing
Hi Rud, Wasn't the white space used for Musak or some other broadcast use years ago, or was that on an FM subcarrier? I think it was also used for timing signals at one time. Seems that there used to be a way to pull down the top of the screen scan and see the information. Been a long, long, time and I don't remember exactly everything it was used for, but the idea is not new. 73, Skip KH6TY - Original Message - From: Rud Merriam [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 3:47 PM Subject: [digitalradio] TV Whitespace Testing The FCC is doing testing for the use of broadband wireless in the space between TV channels. See http://www.pcmag.com/article2/0,2704,2250638,00.asp. The challenge is kind of like BPL: preventing interference with any adjacent digital channels. From my reading, it looks like they are trying to sense when adjacent channels are in use and not use that space. This makes sense for a commercial product since it would be a challenge to get users to configure systems to avoid active channels. I wonder if we could get some channels made available for hams? Possible propose using specific whitespaces on a regional basis. The proposal would determine two open channels in an area and use the whitespace between them. For example, channels 18 and 19 here in Houston are not used so they would be an available whitespace. (I am not sure how the digital channel assignments change availability of whitespace.) Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.7/1233 - Release Date: 1/19/2008 6:37 PM
Re: [digitalradio] TV Whitespace Testing
On Sunday 20 January 2008 03:54:39 pm kh6ty wrote: I think it was also used for timing signals at one time. Seems that there used to be a way to pull down the top of the screen scan and see the information. That wasn't white space, that was the VITS. Vertical Interval Test Signal.
[digitalradio] FIR Filters
I have written my own code to design FIR filters using Parks-McClellan. Are there any programs I can use to test the filter by supplying my table of coefficients? This is part of some SSTV code, I wrote the software as I couldn't find what I needed out there on the web. Simon Brown, HB9DRV
Re: [digitalradio] Re: Redefining SSTV operations
Sholto, Patrick, I just assumed that a digital SSTV mode in 500Hz that could send a decent size picture in a reasonable amount of time was impossible. With a standard modulation and a standard compression scheme you are perfectly right, but, perhaps, with some modulation as the one used by Cesco for FDMDV and a very powerful compression scheme, it's perhaps possible. A big challenge in all cases. Then error correction could also be applied... Yes, it would be ideal. 73 Patrick - Original Message - From: Sholto Fisher To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 11:56 PM Subject: Re: [digitalradio] Re: Redefining SSTV operations Patrick, I just assumed that a digital SSTV mode in 500Hz that could send a decent size picture in a reasonable amount of time was impossible. Certainly if it is possible then it would make more sense to look at that approach. Then error correction could also be applied... 73, Sholto KE7HPV. - Original Message - From: Patrick Lindecker [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 2:50 PM Subject: Re: [digitalradio] Re: Redefining SSTV operations Hello Sholto, MFSK SSTV is an analogical SSTV mode with the originality that it is a narrow band SSTV mode (the same as MFSK) and the format of the picture is free (small or big as you want). It would be possible to put some RS prefix (with more bits available than for RS ID) to define the center frequency, format and color. But I'm not sure that the gain would be important as this type of SSTV is an old technology. Better would be a Digital SSTV within 500 Hz and as fast as standard SSTV. 73 Patrick
[digitalradio] Re: Redefining SSTV operations
a very powerful compression scheme, it's perhaps possible. The compression used is .jpg or .jp2 (jpeg-2000) For reasonybly sized pictures 10kb is minimum, 20kb is average size. The quality does deteriorate rapidly below 20kb/picture. The drm-modem (qam-16 mode b) has a raw troughput of 3600bps, 2400bps FEC'd. Means 66 sec for a 20kb picture. A 500hz wide FDM modem of 500hz BW would have 600bps raw, 400bps FEC'd, Means 6 minutes for a 20kb picture. I think this is not practical. btw you can test the quality/size tradeoff with irfanview.
Re: [digitalradio] Re: Redefining SSTV operations
Hello Sholto, MFSK SSTV is an analogical SSTV mode with the originality that it is a narrow band SSTV mode (the same as MFSK) and the format of the picture is free (small or big as you want). It would be possible to put some RS prefix (with more bits available than for RS ID) to define the center frequency, format and color. But I'm not sure that the gain would be important as this type of SSTV is an old technology. Better would be a Digital SSTV within 500 Hz and as fast as standard SSTV. 73 Patrick For information the specifications of SSTV in MFSK16 SSTV in MFSK16 Created by : Nick Fedoseev (UT2UZ) and Denis Nechitailov (UU9JDR) in 2003 Description : It is a SSTV mode without transmission of a synchronization ray, in color or in black and white mode, where the picture may be transmitted among MFSK16 text. The picture format is not fixed as in classical SSTV but variable (limited to small pictures). Multipsk proposes to use the standard 320x256 to take advantage of the SSTV workshop and the stored SSTV pictures. The band of frequencies used is 234,375 Hz (15 x 15,625 Hz), which is the width between extreme peaks of a MFSK16 transmission. The duration of a pixel is exactly 1 ms. In color mode, the colors are transmitted in the following order: Red, Green, Blue. In black and white mode, the black color corresponds to the lower frequency and the white color to the higher frequency. To be recognized, the picture must be MFSK16 prefixed by: * Pic:320x256C; for example for a color picture of 320x256 dimension whose transmission will last 320x256x3x0,001=246 sec, * Pic:320x256; for example for a black and white picture of 320x256 dimension whose transmission will last 320x256x1x0,001=82 sec. - Original Message - From: Sholto Fisher To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 4:45 AM Subject: Re: [digitalradio] Re: Redefining SSTV operations Yes I never quite understood why it only appeared as an MFSK thing. I guess it was because it shares a similar bandwidth with it. I think using a transmitted header (similar to Patrick's Reed Solomon sequence) at the start would be a better way to define picture size colors and it provides an automatic tuning reference - which will be important because unlike regular SSTV you don't really know in advance where the tones are going to be in the narrow digital areas of the bands. 73, Sholto KE7HPV. - Original Message - From: Leigh L Klotz, Jr. [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Saturday, January 19, 2008 7:37 PM Subject: Re: [digitalradio] Re: Redefining SSTV operations The MFSK picture mode isn't tied to MFSK in any logical way, only in the programs. It doesn't use MFSK modulation for the picture, for example. I think your plan is good and intend to put it into place, but others with production digimode programs are better situated to do it now. 73, Leigh/WA5ZNI On Sat, 19 Jan 2008 7:34 pm, Sholto Fisher wrote: Andy, I agree with you - it would be nice to have a general purpose narrow bandwidth image mode which could be used in a stand alone fashion. The problem with MFSK16 SSTV is that it is tied to MFSK16 and you can't receive it if you didn't catch the MFSK Pic: command. Perhaps one of the programmers who frequent this group could invent an analog 500Hz SSTV mode that allows someone listening to start receiving even if they missed the initial Pic: command plus some form of automatic header (like SSTV has now) or Patrick's RS-ID for easy tuning and correct submode selection? 73, Sholto KE7HPV. Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/sked DRCC contest info : http://www.obriensweb.com/drcc.htm Yahoo! Groups Links
Re: [digitalradio] Re: Redefining SSTV operations
Jens, Thanks for information. I had absolutely no idea there was already a narrow band SSTV mode in MMSSTV. Just shows no matter how long you've been a ham there is always something new to learn! I am guessing then that this mode would be legal now on 30m in FCC areas as well as Region 1? I will have to try it out soon! By the way Jens, I have the autospotters running with a higher squelch value which should cut down on some of the busted calls on my spot pages. At some point soon I will enable a filter to exclude autospots if you wish. 73, Sholto KE7HPV. - Original Message - From: Jens Petersen [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 6:19 AM Subject: Re: [digitalradio] Re: Redefining SSTV operations On Sat, 19 Jan 2008 19:33:54 -0800, you wrote: Andy, I agree with you - it would be nice to have a general purpose narrow bandwidth image mode which could be used in a stand alone fashion. The problem with MFSK16 SSTV is that it is tied to MFSK16 and you can't receive it if you didn't catch the MFSK Pic: command. Perhaps one of the programmers who frequent this group could invent an analog 500Hz SSTV mode that allows someone listening to start receiving even if they missed the initial Pic: command plus some form of automatic header (like SSTV has now) or Patrick's RS-ID for easy tuning and correct submode selection? In MMSSTV ver. 1.11G there is 6 narrow SSTV modes (ex. MP140-N), they works as fine as the wide modes, but takes longer time for the same quality. Let's use it on 7.038 (zone 1) and 10.140 -- OV1A Jens Solar Cycle 24 has arrived!
Re: [digitalradio] FIR Filters
An example of the filter design (ignore the numbers in the toolbar please): http://gallery.ham-radio.ch/main.php?g2_itemId=14198g2_imageViewsIndex=2 Simon Brown, HB9DRV - Original Message - From: Simon Brown I have written my own code to design FIR filters using Parks-McClellan. Are there any programs I can use to test the filter by supplying my table of coefficients?
Re: [digitalradio] Re: Redefining SSTV operations
Patrick, I just assumed that a digital SSTV mode in 500Hz that could send a decent size picture in a reasonable amount of time was impossible. Certainly if it is possible then it would make more sense to look at that approach. Then error correction could also be applied... 73, Sholto KE7HPV. - Original Message - From: Patrick Lindecker [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 2:50 PM Subject: Re: [digitalradio] Re: Redefining SSTV operations Hello Sholto, MFSK SSTV is an analogical SSTV mode with the originality that it is a narrow band SSTV mode (the same as MFSK) and the format of the picture is free (small or big as you want). It would be possible to put some RS prefix (with more bits available than for RS ID) to define the center frequency, format and color. But I'm not sure that the gain would be important as this type of SSTV is an old technology. Better would be a Digital SSTV within 500 Hz and as fast as standard SSTV. 73 Patrick
[digitalradio] Narrow SSTV legal in USA on 30M?
Regarding Sholto's idea about using narrow SSTV on 30M, is it legal in the USA. I am set to use MP73N . In a quick band plan check at the ARRL it says... General, Advanced, Amateur Extra classes: 10.100-10.150 MHz: CW, RTTY/Data Nothing about image . -- Andy K3UK www.obriensweb.com (QSL via N2RJ)
Re: [digitalradio] Narrow SSTV legal in USA on 30M?
The rule change that enabled MFSK16 SSTV did so by stating that image modes with a bandwidth less than 500 Hz could be used anywhere data modes were permitted. Search the archived posts around Nov/Dec 2006 for the actual text. So yes, it is completely legal. -Joe, N8FQ On Sun, 20 Jan 2008 19:10:57 -0500 Andrew O'Brien [EMAIL PROTECTED] wrote: Regarding Sholto's idea about using narrow SSTV on 30M, is it legal in the USA. I am set to use MP73N . In a quick band plan check at the ARRL it says... General, Advanced, Amateur Extra classes: 10.100-10.150 MHz: CW, RTTY/Data Nothing about image . -- Andy K3UK www.obriensweb.com (QSL via N2RJ)
Re: [digitalradio] Narrow SSTV legal in USA on 30M?
Great, then I am going to call CQ with MMSSTV MP73-N tonight on 30M On Jan 20, 2008 7:38 PM, Sholto Fisher [EMAIL PROTECTED] wrote: Hi Andy, Yes I am sure it is legal now. I am copying Rick's response to a question about MFSK16 SSTV posted in this group a while back: Rick said: Yes, thanks to Mark, N5RFX, who petitioned the FCC last year, the decision was made to allow any kind of image transmission (analog or digital) in text digital portions of the bands here in the U.S., provided that they are 500 Hz or less in bandwidth. The FCC redefined data to include image when under 500 Hz and can be found at: §97.3 Definitions. (c)(2) Data.Telemetry, telecommand and computer communications emissions having (i) designators with A, C, D, F, G, H, J or R as the first symbol, 1 as the second symbol, and D as the third symbol; (ii) emission J2D; and (iii) emissions A1C, F1C, F2C, J2C, and J3C having an occupied bandwidth of 500 Hz or less when transmitted on an amateur service frequency below 30 MHz. Only a digital code of a type specifically authorized in this part may be transmitted. Here are some interpretations of the ITU Emission Classifications: A1C = DSB AM digital FAX with no subcarrier F1C = FM FAX digital modulation with no subcarrier (MFSK) F2C = FM digital FAX with subcarrier J2C = digital SSB FAX with subcarrier J3C = analog SSB FAX 73, Rick, KV9U - Original Message - From: Andrew O'Brien [EMAIL PROTECTED] To: DIGITALRADIO digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 4:10 PM Subject: [digitalradio] Narrow SSTV legal in USA on 30M? Regarding Sholto's idea about using narrow SSTV on 30M, is it legal in the USA. I am set to use MP73N . In a quick band plan check at the ARRL it says... General, Advanced, Amateur Extra classes: 10.100-10.150 MHz: CW, RTTY/Data Nothing about image . -- Andy K3UK www.obriensweb.com (QSL via N2RJ) -- Andy K3UK www.obriensweb.com (QSL via N2RJ)
Re: [digitalradio] Narrow SSTV legal in USA on 30M?
Hi Andy, Yes I am sure it is legal now. I am copying Rick's response to a question about MFSK16 SSTV posted in this group a while back: Rick said: Yes, thanks to Mark, N5RFX, who petitioned the FCC last year, the decision was made to allow any kind of image transmission (analog or digital) in text digital portions of the bands here in the U.S., provided that they are 500 Hz or less in bandwidth. The FCC redefined data to include image when under 500 Hz and can be found at: §97.3 Definitions. (c)(2) Data.Telemetry, telecommand and computer communications emissions having (i) designators with A, C, D, F, G, H, J or R as the first symbol, 1 as the second symbol, and D as the third symbol; (ii) emission J2D; and (iii) emissions A1C, F1C, F2C, J2C, and J3C having an occupied bandwidth of 500 Hz or less when transmitted on an amateur service frequency below 30 MHz. Only a digital code of a type specifically authorized in this part may be transmitted. Here are some interpretations of the ITU Emission Classifications: A1C = DSB AM digital FAX with no subcarrier F1C = FM FAX digital modulation with no subcarrier (MFSK) F2C = FM digital FAX with subcarrier J2C = digital SSB FAX with subcarrier J3C = analog SSB FAX 73, Rick, KV9U - Original Message - From: Andrew O'Brien [EMAIL PROTECTED] To: DIGITALRADIO digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 4:10 PM Subject: [digitalradio] Narrow SSTV legal in USA on 30M? Regarding Sholto's idea about using narrow SSTV on 30M, is it legal in the USA. I am set to use MP73N . In a quick band plan check at the ARRL it says... General, Advanced, Amateur Extra classes: 10.100-10.150 MHz: CW, RTTY/Data Nothing about image . -- Andy K3UK www.obriensweb.com (QSL via N2RJ)
[digitalradio] CQ narrow SSTV 10134 tonight
I will CQ periodically tonight on 10134 USB running MMSSTV MP73-N narrow mode. Until 04 UTC, probably at 15, 30, 45 and 00 minutes. Andy K3UK
[digitalradio] RFI Identification
All, I have an RFI problem that I'm trying to identify. It's a continuous pulse noise that pops on every 1/2 second. The timing between each pulse is perfect (about 0.533 seconds) and doesn't seem to change. The noise is spread accross all HF bands and on some days it seems to creep up into the 100MHz range; it's also stronger on the lower frequencies. The signal is directional and goes from almost nothing to S-8 with the antennas pointed south. The noise appeard suddenly in December and has not stopped. I have a recording and would appreciate any suggestions. Thanks, Tony -K2MO
Re: [digitalradio] RFI Identification
Hello Tony,
I use a portable shortwave broadcast radio to find noise sources. I just walk
around to where it gets stronger, then fades. I have found leaky insulators on
power poles, etc. Good Luck.
Howard K5HB
- Original Message
From: Tony [EMAIL PROTECTED]
To: digitalradio@yahoogroups.com
Sent: Sunday, January 20, 2008 6:59:02 PM
Subject: [digitalradio] RFI Identification
All,
I have an RFI problem that I'm trying to identify. It's a continuous
pulse noise that pops on every 1/2 second. The timing between each pulse
is perfect (about 0.533 seconds) and doesn't seem to change.
The noise is spread accross all HF bands and on some days it seems to
creep up into the 100MHz range; it's also stronger on the lower
frequencies. The signal is directional and goes from almost nothing to
S-8 with the antennas pointed south.
The noise appeard suddenly in December and has not stopped. I have a
recording and would appreciate any suggestions.
Thanks,
Tony -K2MO
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[digitalradio] Re: RFI Identification
Tony, a long shot butI did a search on 0.533 second pulses and found a reference to motion detectors with 0.533 second dwell time. Did someone get a new motion detector for Christmas ? Andy K3UK I did a search on --- In digitalradio@yahoogroups.com, Tony [EMAIL PROTECTED] wrote: All, I have an RFI problem that I'm trying to identify. It's a continuous pulse noise that pops on every 1/2 second. The timing between each pulse is perfect (about 0.533 seconds) and doesn't seem to change. The noise is spread accross all HF bands and on some days it seems to creep up into the 100MHz range; it's also stronger on the lower frequencies. The signal is directional and goes from almost nothing to S-8 with the antennas pointed south. The noise appeard suddenly in December and has not stopped. I have a recording and would appreciate any suggestions. Thanks, Tony -K2MO
Re: [digitalradio] Re: Redefining SSTV operations
Patrick, The advantage of the MFSK analog picture mode is that it is already widely implemented, and almost all implementors of MFSK have it. Your RSID is now available in open source C++ pocketdigi so I suspect it will be incorporated into more programs as well. Put the two together and the mode will be widely available fairly soon. 73, Leigh/WA5ZNU On Sun, 20 Jan 2008 3:14 pm, Patrick Lindecker wrote: Sholto, Patrick, I just assumed that a digital SSTV mode in 500Hz that could send a decent size picture in a reasonable amount of time was impossible. With a standard modulation and a standard compression scheme you are perfectly right, but, perhaps, with some modulation as the one used by Cesco for FDMDV and a very powerful compression scheme, it's perhaps possible. A big challenge in all cases. Then error correction could also be applied... Yes, it would be ideal. 73 Patrick - Original Message - From: Sholto Fisher To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 11:56 PM Subject: Re: [digitalradio] Re: Redefining SSTV operations Patrick, I just assumed that a digital SSTV mode in 500Hz that could send a decent size picture in a reasonable amount of time was impossible. Certainly if it is possible then it would make more sense to look at that approach. Then error correction could also be applied... 73, Sholto KE7HPV. - Original Message - From: Patrick Lindecker [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Sunday, January 20, 2008 2:50 PM Subject: Re: [digitalradio] Re: Redefining SSTV operations Hello Sholto, MFSK SSTV is an analogical SSTV mode with the originality that it is a narrow band SSTV mode (the same as MFSK) and the format of the picture is free (small or big as you want). It would be possible to put some RS prefix (with more bits available than for RS ID) to define the center frequency, format and color. But I'm not sure that the gain would be important as this type of SSTV is an old technology. Better would be a Digital SSTV within 500 Hz and as fast as standard SSTV. 73 Patrick
[digitalradio] Re: RFI Identification
If this turns out to be the motion detector, or anything that you identify, please send me a screenshot or the sound file so I can put it up on our radio interference Yahoo forum. Check out QRZ.COM to get my email address. Thank you! Frank, K2NCC http://groups.yahoo.com/group/radiointerference/
Re: [digitalradio] FIR Filters
Simon, Check this out: http://www.dspguru.com/sw/tools/filtdsn.htm I have tried ScopeFIR so far. Regards, Sergio, EA3DU Mensaje original De: [EMAIL PROTECTED] Recibido: 20/01/2008 23:15 Para: Asunto: [digitalradio] FIR Filters I have written my own code to design FIR filters using Parks- McClellan. Are there any programs I can use to test the filter by supplying my table of coefficients? This is part of some SSTV code, I wrote the software as I couldn't find what I needed out there on the web. Simon Brown, HB9DRV
