Re: [digitalradio] HFLINK Comments to ARRL on Development of New HF Digital Comm Protocols
OK so what we have here is a failure to communicate ? --- expeditionradio <[EMAIL PROTECTED]> wrote: > Please click here to read the HFLINK recommendation > comments: > http://www.hflink.com/arrl/ > > Background > On 22 Feb 2007, the ARRL announced that it seeks > comments from > amateurs concerning development of an open-source, > non-proprietary, > data communications protocol suitable for use by > radio amateurs over > HF fading paths. > > ARRL's announcement was discussed at length in the > HFLINK Forum > and via private correspondence. > > On 15 May 2007, HFLINK respectfully submitted > comments in response > to ARRL's announcement. > > Read on the web: > http://www.hflink.com/arrl/ > > Regards, > Bonnie Crystal KQ6XA > HFLINK Founder > > Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get online. http://smallbusiness.yahoo.com/webhosting
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
At 01:36 AM 5/17/2007, you wrote: >It has been long usual to define the frequency of an RTTY signal as the >RF frequency of the mark tone. And so on. Really ? In my 37 years I have always seen it given as dial frequency. Reason: RTTY has fixed tones - never changes. Therefore if you give the dial frequency there is no math to be done just tune and go. You will be right on.
Re: [digitalradio] Re: 30 meter PSK
I was on 30 meters last night up in the automatic subband just above 10.140 (dial frequency 10.140 to 10.141 USB + audio), and I did hear a number of stations, particularly K3MQ. I did copy KB9UMT but was difficult to get the entire call for sure, due to quite a few hits, but based on reading his comments on the reflector, I am sure it was his station. Have you 30 meter operators really found PSK31 to be a good choice of digital mode for this band? I found many hits from QRN as PSK31 has never worked well for me on noisy bands compared to some other more robust modes. I tried calling on DEX11/FEC using the RSID and the waterfall video ID, but no luck. Summer QRN is not quite as bad as 40 meters, but it is still quite severe compared to the relative quiet of 20 meters. The other problem is what I expected, where Pactor stations will suddenly come up on frequency and completely wipe out the area from 10.140 and up and there would be no copy at all for a while on the PSK stations that were covered up. At one point three stations were blocked at my location. Any particular reason why the 10.140 automatic subband was selected for keyboard contacts? The area from 10.130 to 10.140 seems like the very best location for digital keyboard modes because you are not required to be in the automatic subbands and what else is in that part of the band except for the VE3TO beacon? Maybe other regions have different beacons? Most CW operation tends to be below the commercial RTTY station and typically stay below 10.125. This morning I hear at least at least 4 CW stations below 10.125 and two are at least S9. Then there is the VE3TO beacon on 10.132 and that is coming in at S9 as well. Then it is quiet up to 10.140 where there is a Pactor 3 station that is S9 + 10 dB and takes up quite a bit of the area above 10.141 dial frequency and would completely block any possibility of PSK31 or any other keyboard digital mode in that part of the band here in the northern midwest U.S. Have any of you tried modes other than PSK31 on 30 meters? If so, which ones do you find work the best and can still maintain 40 + wpm speeds like PSK31? Any interest in operation outside of the automatic subband? 73, Rick, KV9U
Re: [digitalradio] Re: 30 meter PSK
At 08:45 AM 5/17/2007, you wrote: >Have any of you tried modes other than PSK31 on 30 meters? If so, which >ones do you find work the best and can still maintain 40 + wpm speeds >like PSK31? I have been doing a bit of Amtor and Pactor when I feel up to it. Still not 100% since having 1/2 a lung removed.
Re: [digitalradio] Re: 30 meter PSK
Plain ole RTTY works well, and just about the only digital I hear there most of the time. 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: "John Becker" <[EMAIL PROTECTED]> To: Sent: Thursday, May 17, 2007 10:01 AM Subject: Re: [digitalradio] Re: 30 meter PSK > At 08:45 AM 5/17/2007, you wrote: > > >Have any of you tried modes other than PSK31 on 30 meters? If so, which > >ones do you find work the best and can still maintain 40 + wpm speeds > >like PSK31? > > I have been doing a bit of Amtor and Pactor when I feel up to it. > Still not 100% since having 1/2 a lung removed. > > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/drsked/drsked.php > > Yahoo! Groups Links > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.467 / Virus Database: 269.7.1/805 - Release Date: 5/15/2007 10:47 AM > >
[digitalradio] Meteor Scatter Basics
Andy: Congratulations on the 6 meter MS contacts. Since it is primarily a digital mode, I thought I'd arrange a few general theory notes and tips on meteor scatter to help those that may be new to the mode. Let me know what you think - it's unedited... Tony KT2Q __ Why Meteor Scatter? Meteor scatter can be used to make VHF contacts when there are no other propagation modes available. The earth's atmosphere is constantly being bombarded by a low-level meteor shower and some of these particles produce ionized trails that reflect radio waves out to 1300 miles. Time of Day: Hourly meteor rates vary with the time of day due to the earths rotation into and away from it's orbital direction around the sun. In the morning, the forward-facing earth runs a collision course with meteors increasing the number reaching the atmosphere and intensifying the ionized trails left behind due to the combined speed of the two bodies. In the evening, the meteors reaching earth are those with enough speed to overtake it; the maximum meteor rate occurs at 6am and the minimum at 6pm. Generally speaking, it's best to operate a few hours either side of the 6am peak; expect diminished conditions when operating near the 6pm lull. Seasonal Changes There is a noticible change in raido meteor activity during the year. Seasonal changes in meteor rates are said to be caused by the non-uniform density of space debris along the earth's orbit. Peak activity occurs in June and July; a lull occurs in February. Signal Characteristics: It's easy to distinquish the short bursts of underdense radio meteors from other types of propagation. Signals 'pop' out of the noise and usually last a second or less. Doppler shift can occur due to the motion of the meteor and the drifting motion of the inoized trail. Overdense meteor reflections (big rock) can sometimes last for a minute or more and mimic a sudden Es opening. These are far and few between though and are more common during major showers. If you'd like to hear what they sound like, I have a few radio meteor recordings and videos at http://tim-tom1.magix.net/ . The MS effect on frequency Radio meteor signal strength and duration vary exponentially with frequency. The higher the frequency the weaker the signals, the shorter the 'ping'. This is why it's easier to make contacts on 6 meters than it is on 2 meters and above. The hourly meteor rate is effected by frequency as well. MS on HF? Radio meteors happen on HF all the time. As long as the HF frequency is below the MUF and the station is within meteor scatter range (1200 miles) it should be possible to use meteor scatter to work that station. This is a great way to make use of a "dead" 10 meter band at night! QSO Time A meteor scatter QSO can take as little as 2 or 3 minutes, but it's not uncommon to wait 30 minutes or more to complete a contact. Meteor rates can suddenly change for the worse one hour only to pick up the next so persistence is key. Which WSJT Mode? The 441 mode is less sensitive than JT6M, but can decode very short pings. This makes it more suitable for meteor scatter on 2 meters and above. Radio meteor reflections tend to last longer on 6 meters so the JT6M mode is more suitable. Mode choice depends on conditons at the time. If pings happen to be longer than usual, use JT6M to take advantage of the sensitivity (JT65 is not suitable for MS). Power / Antennas There are quite a few stations running 100 watts and a dipole on 6 meters with good results. Of course a gain antenna will increase your success rate, but it does show how little it takes to get on the air. The antenna / power 'issue' is more of a factor on 2 meters and 432 so a good size beam (or two) and a bit of power will do nicely. Skeds / Callng frequencies Random meteor scatter QSO's take place all the time, but the majority of contacts are made by sked. The internet meeting place is Ping Jockey http://www.pingjockey.net/cgi-bin/pingtalk . The 6 meter calling frequency is 50260 and 144140 on 2 meters. Tony KT2Q
[digitalradio] Meteor Scatter Basics
Andy: Congratulations on the 6 meter MS contacts. Since it is primarily a digital mode, I thought I'd arrange a few general theory notes and tips on meteor scatter to help those that may be new to the mode. Let me know what you think - it's unedited... Tony KT2Q __ Why Meteor Scatter? Meteor scatter can be used to make VHF contacts when there are no other propagation modes available. The earth's atmosphere is constantly being bombarded by a low-level meteor shower and some of these particles produce ionized trails that reflect radio waves out to 1300 miles. Time of Day: Hourly meteor rates vary with the time of day due to the earths rotation into and away from it's orbital direction around the sun. In the morning, the forward-facing earth runs a collision course with meteors increasing the number reaching the atmosphere and intensifying the ionized trails left behind due to the combined speed of the two bodies. In the evening, the meteors reaching earth are those with enough speed to overtake it; the maximum meteor rate occurs at 6am and the minimum at 6pm. Generally speaking, it's best to operate a few hours either side of the 6am peak; expect diminished conditions when operating near the 6pm lull. Seasonal Changes There is a noticible change in raido meteor activity during the year. Seasonal changes in meteor rates are said to be caused by the non-uniform density of space debris along the earth's orbit. Peak activity occurs in June and July; a lull occurs in February. Signal Characteristics: It's easy to distinquish the short bursts of underdense radio meteors from other types of propagation. Signals 'pop' out of the noise and usually last a second or less. Doppler shift can occur due to the motion of the meteor and the drifting motion of the inoized trail. Overdense meteor reflections (big rock) can sometimes last for a minute or more and mimic a sudden Es opening. These are far and few between though and are more common during major showers. If you'd like to hear what they sound like, I have a few radio meteor recordings and videos at http://tim-tom1.magix.net/ . The MS effect on frequency Radio meteor signal strength and duration vary exponentially with frequency. The higher the frequency the weaker the signals, the shorter the 'ping'. This is why it's easier to make contacts on 6 meters than it is on 2 meters and above. The hourly meteor rate is effected by frequency as well. MS on HF? Radio meteors happen on HF all the time. As long as the HF frequency is below the MUF and the station is within meteor scatter range (1200 miles) it should be possible to use meteor scatter to work that station. This is a great way to make use of a "dead" 10 meter band at night! QSO Time A meteor scatter QSO can take as little as 2 or 3 minutes, but it's not uncommon to wait 30 minutes or more to complete a contact. Meteor rates can suddenly change for the worse one hour only to pick up the next so persistence is key. Which WSJT Mode? The 441 mode is less sensitive than JT6M, but can decode very short pings. This makes it more suitable for meteor scatter on 2 meters and above. Radio meteor reflections tend to last longer on 6 meters so the JT6M mode is more suitable. Mode choice depends on conditons at the time. If pings happen to be longer than usual, use JT6M to take advantage of the sensitivity (JT65 is not suitable for MS). Power / Antennas There are quite a few stations running 100 watts and a dipole on 6 meters with good results. Of course a gain antenna will increase your success rate, but it does show how little it takes to get on the air. The antenna / power 'issue' is more of a factor on 2 meters and 432 so a good size beam (or two) and a bit of power will do nicely. Skeds / Callng frequencies Random meteor scatter QSO's take place all the time, but the majority of contacts are made by sked. The internet meeting place is Ping Jockey http://www.pingjockey.net/cgi-bin/pingtalk . The 6 meter calling frequency is 50260 and 144140 on 2 meters. Tony KT2Q
Re: [digitalradio] Meteor Scatter Basics
Tony, Thank you for the basics tutorial. I would like to comment that those who downloaded the WSJT example audio files may use them to experiment what is heard. I used Audacity, a free audio editor, which plays the files and lets you see simultaneously the wave stream. It is interesting to hear the sounds and see the amplitude envelope simultaneously. I used that method when playing the FSK441 and JT6M examples, and I found it quite enlightening to compare what WSJT shows with what Audacity plays and displays. I could not play both simultaneously, but found interesting to relate the envelope with the display in WSJT 5.9.7 73, Jose, CO2JA __ V Conferencia Internacional de Energía Renovable, Ahorro de Energía y Educación Energética. 22 al 25 de mayo de 2007 Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.cujae.edu.cu/eventos/cier Participe en Universidad 2008. 11 al 15 de febrero del 2008. Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.universidad2008.cu
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
Danny Douglas is correct with his information. With RTTY, most of the frequencies have been mark tone, not carrier frequency since most serious RTTY operators used on FSK and not AFSK. Since there is over 2000 Hz difference between the carrier and the tone, if using AFSK high tones of 2125/2295 with 170 Hz shift, and over 1000 Hz with AFSK low tones, you would have widely different spotting frequencies depending upon whether you were using FSK or AFSK. Some rigs will read the FSK mark frequency as a direct readout on the display. There were some rigs that read the space frequency instead of the mark, but the normal convention was to read the mark frequency and the 170 Hz difference would not be as difficult to find compared with a discrepancy of over 2000 Hz. If you have a rig that is designed for RTTY FSK operation, you might try tuning in a steady carrier in RTTY mode and set it at 2210 Hz which is a convenient number averaging the standard high tones of 2125/2295 for 170 Hz shift on a waterfall and read the dial frequency. Then switch to USB and record the new dial frequency when the waterfall shows 2210 Hz. Finally, switch to LSB mode and record the dial frequency. They will be VERY different dial frequencies, right? As an experiment with my ICOM 756 Pro 2, here are my rough results to the nearest 10 Hz: RTTY 28233770 Hz USB 28231460 Hz (difference of 2310 Hz from RTTY mode) LSB28235900 Hz (difference of 2130 Hz from RTTY mode) note also that the difference of 2310 and 2130 is 180 Hz which if I did this more exactly, would likely be 170 Hz, which is the shift between mark and space. If someone gave you the FSK mark frequency, and you were using AFSK and turned your dial to the mark frequency, you would be placing your carrier frequency more than 2000 Hz off from where you are expecting to tune in the signal. It just will not be there. Remember, when you are operating in SSB mode, your display is reading out the carrier frequency. Of course there is almost no carrier since it is suppressed many dB down. That is why when you toggle between USB and LSB, your dial frequency remains the same. You are just showing the carrier center frequency which does not change. What has complicated things is the proliferation of new modes, most of which are being operated with sound cards as AFSK. Some of these modes are extremely wide, as much as 2 kHz wide at this time. So we don't really think of a mark and space with PSK and OFDM, etc. We just have some wide band signals with various tones within a range of frequencies. It is easier to just specify the dial frequency if they have a fixed relationship to the carrier as an AFSK mode. This could be true of 141A or MT-63. With narrow modes, such as PSK31, the signal could be well up the band assuming USB is being used which is SOP these days. 73, Rick, KV9U John Becker wrote: > In my 37 years I have always seen it given as dial frequency. > Reason: RTTY has fixed tones - never changes. Therefore > if you give the dial frequency there is no math to be done > just tune and go. You will be right on. > > > >
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
Hello John, Technology is changing this concept. I was recently "re-educated" on this topic after returning from a ham radio hiatus. Like you, I grew up on the principle you mentioned in your message, the transmit dial frequency is the Mark frequency. This statement is no longer true or false! The answer to what your dial is displaying is... "it depends"! In the old days, you would log and spot a RTTY station using the dial frequency. This was because FSK was generated by switching a small capacitance in and out of parallel with the main VFO capacitor. The Drake equipment (T4X, TR4, and RV4) had a solder tab sticking out the side of the VFO "can" for this connection. Your dial frequency WAS your Mark frequency and you shifted 850 Hz or 170 Hz lower when the external capacitance was switched into the circuit. Today, the modern transceiver dial frequency may indicate the suppressed carrier frequency, the Space frequency, the Mark frequency, or whatever you want (in some cases). There doesn't seem to be any consistency among the manufacturers, and in some cases within the same manufacturer. For a particular transceiver, you may be able to determine what the dial frequency is from reading the operations manual, but sometimes not! You can determine what a transceiver is doing by dialing in 28.100 MHz and transmit in RTTY. Using an external frequency counter or receiver, you can then find your FSK Mark carrier. It may be the same as the dial or not. It's a crap-shoot! Here are some examples why the newer technology has become a quagmire... My Kenwood TS-450 transceiver dial frequency IS the Mark frequency. This is described on Page 38 in the operations manual. The dial displays the Mark frequency, independent of the shift width or polarity. Likewise, the Ten Tec Orion II displays the Mark frequency when operating in FSK mode. But there are a variety of other systems... My Kenwood TS-950S (and TS-950SDX) transceiver dial frequency displays the SPACE frequency. This is described on Page 32 (Page 36) in the operations manual. It shows the Space frequency independent of the shift width or polarity. The dial frequency will be off by 170 Hz, hardly noticeable by most operators. I also have an Icom 756 Pro III. The operations manual is vague regarding the relationship between dial frequency and Mark frequency in this transceiver. I can't find a specific statement in the book, but from experience it appears the dial frequency is the suppressed carrier frequency. The Yaesu FT-920 throws yet another layer of configuration possibilities. This transceiver allows you to program the dial frequency to display Mark, Space, or the Center frequency! See Page 56 in the FT-920 manual which describes Menu Item U-45. Likewise, the FT-1000MP provides menu 6-3 which allows the user to set the transceiver displayed frequency to their choice. The default setting is to display the Mark frequency. See Page 54 of the operations manual. With the introduction of computer soundcards being used to generate RTTY tones, transceivers without FSK capabilities can now be used for digital communications. In this case, the dial frequency is the suppressed carrier frequency. The transceiver has no clue what tones are being broadcast through its audio chain! The contesting (N1MM) and logging (DXKeeper) software I use in my station have provisions to adjust to any method of FSK or AFSK frequency logging. Once you know what your specific transceiver dial is telling you, you can adjust these software so it logs and spots the exact Mark frequency. Welcome to the digital revolution! 73 de Bob - KØRC in MN - Original Message - From: John Becker To: digitalradio@yahoogroups.com Sent: Thursday, May 17, 2007 8:14 AM Subject: Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency At 01:36 AM 5/17/2007, you wrote: >It has been long usual to define the frequency of an RTTY signal as the >RF frequency of the mark tone. And so on. Really ? In my 37 years I have always seen it given as dial frequency. Reason: RTTY has fixed tones - never changes. Therefore if you give the dial frequency there is no math to be done just tune and go. You will be right on.
[digitalradio] Re: VFO Dial Frequency, Audio Frequency, Centre Frequency
The confusing use of 4 different methods of calling out channel frequency for RTTY and FSK, is not a problem unique to ham radio. The entire communication industry, regulatory entities, and standard organisations of the world, have all been using a variety of methods to describe channel frequency for various types of signals, for various reasons. In some situations for commercial or governmental communications, the confusion between the different channel frequency methods has led to significant problems. The seriousness of this problem may not really be quite so intense in ham radio for HF digital, and sometimes it can be humorous. I had to laugh at the irony of the complaint from one operator who was very angry, because a "DX spot" he had obtained from the cluster for a RTTY DX station wasn't exactly on the frequency when he tuned it! On the other hand, digital HF networks used by hams for data communications rely upon vary accurate frequency netting. It is advantageous for the members of those nets to understand the standard method for describing channel frequency used by that net. Bonnie KQ6XA
