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Re: AMTOR?
hI,
I am happy to make amtor connections if anyone is interested. I put out calls occasionally on 20m around 14082 and 14107.5 but i haven't had any connections. Regards Dave VK2NA SECAL VKNA
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AUTEX test results ,further test meetings, weekly net.
Andrew O'Brien
I participated in a three-way QSO last night testing the mode "Autex" that is part of Multipsk . A ham in South Africa mentioned he feels it is a better mode/concept than JS8call or FSQcall, so we tried it. It worked quite well between Long Island, Buffalo and Wisconsin on 40M. A few Europeans are interested so I will be on the air and setting up a "meeting" at 2200 UTC tonight and tomorrow (Tuesday and Wednesday( . It worked quite well between Long Island, Buffalo and Wisconsin on 40M. 7080 USB Also, Mike WB9EZB will be holding a weekly AUTEX net on 7080 on Mondays at 6. 30PM CENTRAL USA time. Andy
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Re: Autex mode + EM mode ("conference" modes)
#autex
Patrick Lindecker
Hello Andy,
As you are speaking of Autex, here is a small presentation of the two modes on Multipsk (freeware part), to work on “conference” between several hams.
· The most simple is the “Extended message“. The number of Hams is limited by the AF bandwidth. The mode is sensitive but it is not controlled: there is no guarantee that the others Hams have received your message. So the meeting can be local or not. · Most complete is the Autex mode. There is a guarantee that the other Hams have received your message. So beyond 2 Hams, it can only be local, because the risk would be that one Ham blocks the others if his/her conditions are poor.
73 Patrick
1) The "Extended Message" pseudo-mode The EM (Extended Message) is a “pseudo-mode” because it can be used in parallel of any mode (BPSK31...). Its main use is to give the possibility to have simultaneous QSO (at standard speed) with different Hams, as messages are displayed on the waterfall. So everyone can see these messages and possibly answer.
This system can be used for a small meeting. The number of participants is limited only by the bandwidth.
The sensitivity is -14 dB comparable to Olivia or MFSK16, at 47 wpm. It is a free error transmission. Example of an EM « CQ » message displayed on the waterfall.
However there is no control about the reception of your message by the other Hams (it’s a one way system not an ARQ sytem).
2) Autex It is an ARQ system extended to several persons. AUTEX The AUTEX modes permits to organize a meeting between 2, 4, 7 or 13 people. Text messages can be transmitted from any person to any other person participating to the meeting, in pseudo full duplex (protocol one, not physical one), each person being sure that his messages will be read by the other participants. So, each one will be sure to read all the texts sending by the other participants to the meeting. It is a mode without errors (if en error is detected, the frame is re-transmitted until complete reception). So, it can be considered as an extended ARQ mode. AUTEX is composed of 4 different modes (for 2, 4, 7 and 13 people), each one with a different RS ID. General description of the AUTEX4 mode, for 4 people Baud rate : 250 bauds for the "Master” (the one who initiates the meeting) and 83.33 bauds for the 3 "Slaves" (users) Rough speed : 500 bits/s at 250 bauds and 166.6 bits/s at 83.33 bauds or 625 wpm at 250 bauds and 208 wpm at 83.33 bauds User speed : the maximum, in the best conditions, for each participant, is about 42 wpm (same order as PSK31) Modulation : QPSK (2 bits per symbol) Reception mode: only one side (USB or LSB), USB is recommended Character set : ASCII +ANSI characters (8 bits compressed or not) Shape of pulse : square root of elevated cosine (index=1) Bandwidth : 500 Hz in 250 bauds and 167 Hz in 83.33 bauds Demodulation : coherent, Synchronization: symbol by using the signal, the phase ambiguity of 90° being solved by using a prefix Coding: Reed Solomon Interleaving : no Scrambling : yes Memory ARQ: yes, soft one on each I/Q levels Pmean/Ppeak: 0.5 Lowest S/N (250 bauds): -3 dB Before each frame, it is transmitted a (symbol) synchronization sequence, followed by a specific prefix to solve the phase ambiguity and to transmit the way to interpret the frame which follows. The frame contains a preamble for control data, then the message (possibly compressed) and, finally the text which appears in the secondary channel which contains the callsign and various information (sent two characters by two characters in a rotating way). A Reed-Solomon code checks the frame and can fix up to 8 errors. Other AUTEX modes The "Slave" baud rate is always the same for all AUTEX modes: 83,33 bauds In AUTEX for 2 people, the baud rate of the "Master" is equal to 83.33 bauds, so the bandwidth is equal to 167 Hz.
-----Message d'origine-----
I took a look again at Autex in Multipsk this morning. I think I remember using it in the past , but not much . I note that Patrick’s documentation suggests using 7080 and 14080 among other QRG. 14080 carries a lot of FT4 traffic these days . So I have moved up to 14082 and will listen there today for any AUTEX activity . As darkness arrives here in the north eastern New York I will listen 7080 . Bradley , when you have used it from South African , who are your partners ? Other ZS hams ? I note that this mode has a “start a meeting “ button . Perhaps the ham radio version of Zoom :)
Andy K3UK
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Autex mode
Andrew O'Brien
I took a look again at Autex in Multipsk this morning. I think I remember using it in the past , but not much . I note that Patrick’s documentation suggests using 7080 and 14080 among other QRG. 14080 carries a lot of FT4 traffic these days . So I have moved up to 14082 and will listen there today for any AUTEX activity . As darkness arrives here in the north eastern New York I will listen 7080 . Bradley , when you have used it from South African , who are your partners ? Other ZS hams ?
I note that this mode has a “start a meeting “ button . Perhaps the ham radio version of Zoom :) Andy K3UK
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Re: digital modes on 2m 70cm
Bruce
Hi Graham
You brought back a memory of when I was
working for the County as a radio tech. I was troubleshooting a
pesky problem with a speed radar gun used by the Sheriff. The
needle would hang up about half scale instead of falling to zero.
Out of desperation I installed a headphone jack in the Doppler
Radar audio path. I found the switching power supply was
introducing a whine which was seen as a "signal." After I repaired
the power supply, I took it on a test run. With the headphones I
could hear the Doppler shift as I panned the dish antenna. Pan the
signals up a stairway and I could hear the steps. I could tell
where walls were. (Note: this could be developed into a useful
tool for the blind) If I aimed it at a vehicle that was using a
stick shift I could hear the shift points. Hmmm I thought what
would it do with Military aircraft landing at a nearby Navy base?
We drove to a frontage road that crossed the landing pattern,
stopped and waited. Sure enough, a "Tom Cat F16 was landing. There
are no "sights" on the gun to aim the marrow beam - but I was able
to get a return and the audio tone went thru a screaming 8-10 KHz
and the meter pegged hard well above 100 MPH!! I did not stick
around for the MP's to show up! I wonder if the F16 IFF alarm went
off?!
73 Bruce WA6DNT
On 10/21/2020 1:34 PM, Graham wrote:
Bruce
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Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)
Sergei Podstrigailo
Hello All,
HF Pager for Windows 2.90 is released: http://www.dxsoft.com/hfpagerw.zip HF Pager versions history 2.90 Baud rate of 23.44 Bd was added. The signal bandwidth in this mode is about 500 Hz. The center frequency of the audio signal at this speed is about 1711 Hz and cannot be changed by the user. The "Setup/Beacon & APRS/Reset beacon timer on a message sending" option was made. Any COM-port of COM1...COM99 can be used for PTT control or GPS-receiver connection. Minor improvements of the program interface were made. 2.88 Some minor bugs were fixed. 2.87 The "Carrier detector" was radically redesigned. A symbol sync was slightly improved Bugs in the Error Rate calculation were fixed. 2.86t The test version - carrier detector is disabled. 2.85 The signal quality indicator (Error Rate) is been writing into the text of the received message. Baud rate of 46.88 Bd was added. The signal bandwidth in this mode is about one kilohertz, so use it in those parts of the bands in which wide band digital modes are allowed. The center frequency of the audio signal at this speed is about 1711 Hz and cannot be changed by the user. To reduce the load on the processor, you can reduce the number of simultanious decoding baud rates (Setup / RX Speeds). [...] -- Best regards, Sergei mailto:amx2@dxsoft.com Windows HAM radio software at http://www.dxsoft.com
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Graham
5 Mhz / 3.5 / 1.8
Out of interest in the week, using one of the kikwi web sdr's , and the last version of ros-hf-4 , using 50 watts and 40 ft vertical , with Rx just in daylight ..I tried 3 band test over the 'pond' ,which highlighted the path was open, even down to 160 , with the 40 ft vertical The modes are self synching , but , must be slight loss due to the sdr&www being in the circuit , may be 2 db , as ros 4 should decode past -20 73-Graham g0nbd  Quite good results , first on 80 meters dropped a few characters of the 'quick brown fox' test message at 50 watts . increase to 75 watts , 100% copy ros screen  Test on 160, same ae , 100 watts ,ros failed , no lock Changed to opera op4 as set for 160 , produced a spot at -28 db , 7 or 8 db lower than the ros-hf-4 limit , with 50 watts opera beacon is a week signal mode , 2020-10-18 21:50:53 G0NBD IO83LK G8FZKSDR FN54LE 4.760Km 1.836 -28 Op4_||_~28dB final check on 5 ...opera 1-4-1 has a 15 chr plain text mode , with the RX now in darkness , power of 10 watts Moved to 5 MHz , same 40 ft vertical , qso mode is fixed at 60 seconds 3 tx recovered 100% 
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Re: digital modes on 2m 70cm
Graham
Bruce
Interesting point on the military aircraft , popular rumer had/has it , that one of the local police , out on traffic speed duty , close to a scottish air base , out of curiosity , pointed his hand held 'speed gun' at one of the aircraft coming into land , which lit up the counter measures suite , end of career .. Its more to re-radiation , most of the aircraft to day are composite hulls , [one of the reasons for the 11 meter ww2 radar , was aircraft wing was round 35 feet , so it gave a good return signal] so the signals are not as good as in the past , polarisation , probably Horizontal , I would expect the return signal to be modified , dopper plays a part as well , so the decoder needs to have a wide acceptance bandwidth , I think the doppler shift is up to x2 if the target is advancing , first shift tx> a/c then a/c >> rx , at 600 mph , that's round +150 Hz on 2 meter's ? Ive found this write up by two spanish stations using a plotting/ prediction software package to give the expected angles / range , google translate makes a good job of converting to english , just noticed it was back in 2014 , when the decoder was re-worked during the eme testing http://hamlincs.blogspot.com/2014/04/aircraftscatter-144mhz-con-opera.html?fbclid=IwAR3KXz9kxfm9-ePVvANjWkI4iOAfG0JtbV76Jps3TC4TXv3gQZUbTHYgJ5Y This was a scatter spot , from a French 10 watt 70 cm beacon, using a halo round Ae to south of france to paris 704 Kmt , confirmed by the keeper 19:56 432418 F5ZAS de F1RJ Op05 -19 dB F:2% in JN18AT 1390,6 Hz >> Foxsix Htj Yes, Aircraft Scatter, big airplane above Clermont Ferrand (matching with AirScout software).
73-Graham g0nbd
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Re: digital modes on 2m 70cm
Tony
Bruce:
toggle quoted messageShow quoted text
Commercial and military aircraft fly through a sea of RF including megawatt radars that track satellites in space without incident. If there was any risk, big-gun 2 meter EME stations would be outlawed : ) Aircraft scatter is probably not what you imagined - we don't point our antennas at the aircraft. The mode relies on an aircraft crossing the path between stations; when the geometry is right, signal reflecting from the aircraft rises above the noise so the contact can be made. The reflection weakens as the aircraft continues along it's path so the signal doesn't last very long. Range is limited to 400 miles or so. I produced a demo video that shows what A/C scatter looks like on a spectrogram. See: https://www.youtube.com/watch?v=vYkaSuJkYrM Tony -K2MO
On 10/21/2020 12:00 AM, Bruce wrote:
Hi Tony
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Re: digital modes on 2m 70cm
KD7JYK DM09 <kd7jyk@...>
but I did see a video latest week showing the drift briefly caused by a plane when using WSPRDoppler shift of the signal bouncing off the craft, or sudden uncontrolled skewing of the crafts flight path when passing through one of a billion RF carriers? As for RF drift, yes, the basis of "radar". The earliest I've heard noted was the 1920's, when craft, and broadcasts, were becoming more common, although it was noted that RF signals bounced off of metal objects in the late 1880's, with increasing experimentation until the creation of functional radar in the mid-30's. Kurt
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Re: digital modes on 2m 70cm
Andrew O'Brien
but I did see a video latest week showing the drift briefly caused by a plane when using WSPR Andy K3UK
On Wed, Oct 21, 2020 at 12:11 AM KD7JYK DM09 <kd7jyk@...> wrote: "Bouncing signals off of aircraft could that interfere with electronic --
Andy
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Re: digital modes on 2m 70cm
KD7JYK DM09 <kd7jyk@...>
"Bouncing signals off of aircraft could that interfere with electronic systems or communications in the aircraft?"
No, for many reasons. But, in short, think of the amount of RF spew in a radio septic tank such as Los Angeles, and that there are no problems... They fly around in a cloud of GigaWatts, from "DC to Daylight", all signals bouncing off of them, all the time, without issue. Kurt
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Re: digital modes on 2m 70cm
Bruce
Hi Tony
toggle quoted messageShow quoted text
Interesting subject on Airplane scatter on 2 meters. Bouncing signals off of aircraft could that interfere with electronic systems or communications in the aircraft? If you bounced signals off of military aircraft, could that be tracked and bring a visit by MP's? Also what antenna polarization works best for the path ? Do both stations need to be using the same polarization? How do you find stations and frequencies being used and arrange a contact? Thanks for the education. Bruce WA6DNT@juno.com
On 10/18/2020 7:24 PM, Tony wrote:
Andy:
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Re: digital modes on 2m 70cm
Andrew OBrien
Thanks Tony . I have done quite a bit of MS on 6 but nothing on 2M . I’ll try FT8
toggle quoted messageShow quoted text
Andy
On Oct 18, 2020, at 10:24 PM, Tony <73GUDDX@gmail.com> wrote:
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Re: digital modes on 2m 70cm
Tony
Andy:
The most popular VHF modes are FT8 for terrestrial propagation and MSK144 for meteor scatter. You can get an idea what the activity is like by checking out PSK Reporter with the 2 meter filter on. If you're used to 6 meters, you'll find that Sporadic-E and other long distance propagation modes typically happen less frequently on 2 meters and a lot less on 432 so it pays to get email alerts to let you know when the openings occur. If you're looking for daily propagation on 2m and 70cm, aircraft scatter is the most consistent mode out to a few hundred miles. It's easily recognizable by the Doppler shifted signals which FT8 usually handles well. I've attached a PSK Reporter screenshot that shows the distances you might see on 2 meter A/C scatter. The other screenshot will give you an idea what the A/C Doppler is like on 2 meters. There are several amateur satellites that you can try as well. Tony -K2MO
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Re: digital modes on 2m 70cm
Graham
FT8 -(
73-G
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Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)
Sergei Podstrigailo
Hello All,
Android HFpager V3.19 is published: http://www.dxsoft.com/hfpagerdemo.apk https://play.google.com/store/apps/details?id=ru.radial.demo.hfpager https://play.google.com/store/apps/details?id=ru.radial.full.hfpager Decoder was improved. 23.44 Bd and 46.88 Bd speeds were added. Support for x86 and x86_64 Android devices was made To sent message by HFpager from another application, you can "share with it by text" (not by text file). Wednesday, October 14, 2020, 6:26:22 PM, I wrote: SP> AprsGate 0.98 was published: SP> http://www.dxsoft.com/aprsgate.zip SP> AprsGate versions history SP> V0.98 SP> Baud rate of 23.44 Bd was added. The signal bandwidth in this mode SP> is about 500 Hz. SP> The center frequency of the audio signal at this speed is about SP> 1711 Hz and cannot be changed by the user. SP> English help-file was made. SP> V0.97 SP> Baud rate of 46.88 Bd was added. The signal bandwidth in this mode is about one SP> kilohertz. SP> The center frequency of the audio signal at this speed is about SP> 1711 Hz and cannot be changed by the user. SP> To reduce the load on the processor, you can reduce the number of simultanious SP> decoding baud rates (Settings / RX Speeds). SP> The Error Rate of messages containing uncorrectable errors is calculated more accurately now. SP> This version will work till 31 January 2021. SP> [...] -- Best regards, Sergei mailto:amx2@dxsoft.com Windows HAM radio software at http://www.dxsoft.com
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digital modes on 2m 70cm
Andrew OBrien
Ok digital mode folks, now that I have an all mode transceiver that includes 2 mètres and 70cm , where/when is the action ? Is there much action outside of contests ?
Andy K3UK
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Re: QRP success with Opera 2
Graham
Looking back - 8 years Was it really that long ago !
O db , thats round +25 db over the op2 limit 15 mW carrier power would of decoded Be interesting to make the comparison to day ? 73-Graham g0nbd
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Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)
Sergei Podstrigailo
Hello Chiefsfan2,
Monday, September 28, 2020, 8:36:05 AM, you wrote: C> And can u give a little more info C> about aprs gate. Does it have a English help file. AprsGate 0.98 was published: http://www.dxsoft.com/aprsgate.zip AprsGate versions history V0.98 Baud rate of 23.44 Bd was added. The signal bandwidth in this mode is about 500 Hz. The center frequency of the audio signal at this speed is about 1711 Hz and cannot be changed by the user. English help-file was made. V0.97 Baud rate of 46.88 Bd was added. The signal bandwidth in this mode is about one kilohertz. The center frequency of the audio signal at this speed is about 1711 Hz and cannot be changed by the user. To reduce the load on the processor, you can reduce the number of simultanious decoding baud rates (Settings / RX Speeds). The Error Rate of messages containing uncorrectable errors is calculated more accurately now. This version will work till 31 January 2021. [...] -- Best regards, Sergei mailto:amx2@dxsoft.com Windows HAM radio software at http://www.dxsoft.com
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