Date   

Re: digital modes on 2m 70cm

Tony
 

Bruce:

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
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:

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











Re: digital modes on 2m 70cm

KD7JYK DM09
 

but I did see a video latest week showing the drift briefly caused by a plane when using WSPR
Doppler 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


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
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








--
Andy


Re: digital modes on 2m 70cm

KD7JYK DM09
 

"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


Re: digital modes on 2m 70cm

Bruce
 

Hi Tony
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:

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








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

Andy

On Oct 18, 2020, at 10:24 PM, Tony <73GUDDX@gmail.com> wrote:

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









<2M FT8.jpg>
<ACS.jpg>


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


Re: digital modes on 2m 70cm

Graham
 

FT8  -(

73-G


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


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


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 


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


Re: 2 New Modes in Release Candidate: WSJT-X 2.3.0-rc1

Steinar LA5VNA
 

60 sek


LA5VNA Steinar

On 13.10.2020 21:15, Steinar LA5VNA via groups.io wrote:
RX 7038.6 (dial) USB + 2000 Hz this evening (19:15 UTC)
LA5VNA Steinar
On 13.10.2020 10:07, Andrew O'Brien wrote:
What freqs are you using Steinar ?

Andy K3UK





--
Steinar LA5VNA


Re: 2 New Modes in Release Candidate: WSJT-X 2.3.0-rc1

Steinar LA5VNA
 

RX 7038.6 (dial) USB + 2000 Hz this evening (19:15 UTC)

LA5VNA Steinar

On 13.10.2020 10:07, Andrew O'Brien wrote:
What freqs are you using Steinar ?
Andy K3UK


Re: 2 New Modes in Release Candidate: WSJT-X 2.3.0-rc1

Andrew O'Brien
 

What freqs are you using Steinar ?  

Andy K3UK


FST4 on 40M , a success !

Andrew O'Brien
 

Just "because it is there" , Phil W1ZOT and I tested FST4 on 40M tonight and it performed well . 1200 mile path  New York to Texas path. . W1ZOT using 5 watts and me using 3-4 watts with battery pack in the IC-705.  A little tough at 30 seconds but easy at 60 seconds, decoding down to -24 SNR .  Both using homemade antennae (sloper and vertical).   Some of you may recall that this group (when on Yahoo) started the JT65A utilization on HF way back when.  In that same spirit of adventure, Phil and I thought we would give FST4 a whirl.  We have not tried the 120 second variant yet   Joe Taylor intends this mode for LF MW work but it could be useful for HF.  

Andy K3UK


Re: "RTTY and Data" band plans ?

Cliff Fox (KU4GW) <cliffku4gw@...>
 

Hey Andy!
                Below are the ARRL and IARU Region 2 Band plans for the 20 Meter Band. Source of info is on the images below. I just got the one from the ARRL website, but have had the IARU band plan dated October 16, 2016 in a PDF file I downloaded and saved on May 5, 2019. It shows RTTY starting at 14.070 and the IARU region 2 band plan shows DM (Digital Modes) starting at 14.070 also.The bottom image shows both the currency and proposed ARRL band plans with the latter not having been accepted by the FCC yet. The proposed band plan shows 14.105 to 14.150 for RTTY, Narrow and Wide bandwidth data and all ACDS stations. 

ARRL_20_Meter_Bandplan_Oct_09_2020.jpg

IARU_Region_2_20M_Bandplan_Oct_14_2016.jpg


ARRL Current and Proposed 20 Meter Band Plans.jpg

Very 73 de Cliff, KU4GW
Proud Member of the ARRL A-1 Operator Club (*Elected to Full Membership April 11, 2012
DMC # 6362
FT8-DMC #07470
FELD HELL # 0062  
"It's not the class of license that the Amateur holds that matters, it's the class of the Amateur who holds the license!" 



Re: "RTTY and Data" band plans ?

Andrew O'Brien
 

Thanks Tom and Ralph.  Yes, I agree I would need to make sure I am not out of band with my signal.  I don't intend to drop that far down.  However, it has occurred to me that I might sneak below 14065 to operate some digital modes including FT8  IF I had a 'sked" with someone, just to get away from the maddening crowd.  Just for a few minutes. Never on a weekend unless on a WARC band. 
Andy K3UK 

On Thu, Oct 8, 2020 at 12:08 PM Tom W7SUA <tom@...> wrote:
Sure but just no one does unless perhaps a sked. Especially if being
polite and using narrow modes. Would think random CQs down there would
not bear much fruit. Per the FCC regs it is after all the "data subband."

73, tom w7sua



On 10/8/2020 6:24 AM, Andrew O'Brien wrote:
>
> I'm forgetting some of the band plans for digital modes .  In looking at
> the ARRL's band plans  it lists wide swaths of bandwidth simply as "CW,
> RTTY/Data ".  For example 14.000 to 14150 . I never hear any digital
> modes from the USA below 14066.  Can any digital modes (attended)
> operate as low as 14.003?
> --
> Andy K3UK







--
Andy


Re: "RTTY and Data" band plans ?

 

Sure but just no one does unless perhaps a sked. Especially if being polite and using narrow modes. Would think random CQs down there would not bear much fruit. Per the FCC regs it is after all the "data subband."

73, tom w7sua

On 10/8/2020 6:24 AM, Andrew O'Brien wrote:
I'm forgetting some of the band plans for digital modes .  In looking at the ARRL's band plans  it lists wide swaths of bandwidth simply as "CW, RTTY/Data ".  For example 14.000 to 14150 . I never hear any digital modes from the USA below 14066.  Can any digital modes (attended) operate as low as 14.003?
--
Andy K3UK


Re: "RTTY and Data" band plans ?

Ralph Mowery
 

As long as the signal and sidebands are still above 14.000 you can legally  operate there.  14.003 may be pushing it, but around 14.005 to 14.010 should be ok .  Again you have to be careful and not talk about the dial frequency , but what is actually coming out of the transmitter.

Lets say your dial is at 14.003.  Using some modes and tones and side band selection, you could push the signal below 14.000, but using the other sideband  would be fine as the signal would start at 14.003 and shift higher.

I would not really want to operate anything but CW that low to keep the  CW operators happy.

Ralph ku4pt


On Thursday, October 8, 2020, 09:27:09 AM EDT, Andrew O'Brien <andrewobrie@...> wrote:



I'm forgetting some of the band plans for digital modes .  In looking at the ARRL's band plans  it lists wide swaths of bandwidth simply as "CW, RTTY/Data ".  For example 14.000 to 14150 . I never hear any digital modes from the USA below 14066.  Can any digital modes (attended) operate as low as 14.003?
--
Andy K3UK
_.

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