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Re: New LOCAL Winlink CMS Gateway for VARA RM on 145.060 #VARAFM,#CMS Gateway

 

Location?
Hope you find some ham activity there.? :)


New LOCAL Winlink CMS Gateway for VARA RM on 145.060 #VARAFM,#CMS Gateway

 
Edited

Hello,
I have just setup a temporary CMS Gateway on 145.060, Simplex, 1200 Baud ( Narrow) for the local area.
It is located in the RV Park at 4313 FM 2004, La Marque, TX? 77568 and the antenna is mounted at about 12 ft above Ground Level (AGL)
So the range is unknown.
This is a temporary setup while we are in the local area.? Since I join the 2 PM ragchew and use the same radio Winlink will
not be available from 14:00-15:30.
Please let me know via email if you have problems connecting and I will try to assist.
73? NB5C


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

Understood.? Most of the successful implementations is to have VARA run on a windows PC on the same network as the Linux machine and connect the apps via the network instead of trying to use a virtual machine.? I don't currently have a test rig for this, so will defer to others.
--
Roy Dugger, KD6R


Re: Questions on Running 40m VARA APRS mobile

 

If you want the most availability of the band. Stop sending DX status beacons. Stop double beaconing. Meaning don't send statuses, grid position, or other beacons types. Avoid excessively long comments even. There are lots of things that can be done at the base stations to allow more air time, which can help provide more time for mobile users, or messaging users, of which I think should have priority.
?
There are a lot of things to consider. But most importantly, use the freaking network! Don't let it sit there going to waste. This isn't some nonsense ARES RACES net that's completely worthless. I'm sure someone will love that comment.

Also have contact info on QRZ. In case there is an issue, or some reason someone might want to contact you. Community efforts are the key here.

Get out there, have fun, enjoy the bands, and use APRS!?


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

Auto Tune does not connect, and Ping only works if there is a connection... Ron


Re: Questions on Running 40m VARA APRS mobile

 

Here's my 2 cents...

NO!!! ? You can't do that kind of rate on HF! ? ?
1) ? The transmission time is much longer on VARA than on the usual 1200-baud 2M VHF. ?A simple beacon, especially if it is not in a compressed format like Mic-E, ?can take 20-30 seconds. ? At a two-minute repetition rate, you are occupying 1/5 th to 1/4 of the total capacity of the channel.?
Note that on a random-access channel with no coordinated timing of the users, that if the channel is occupied more than 18-20% of the time, the probability of data collisions between stations goes up sharply. (The so-called Aloha" limit.)

Let's start with this. Not all beacons are alike. Data saving measures are hidden within VARA modems code. Uncompressed beacons are actually compressed within VARA, which is why the math doesn't add up when you look at the data sizes. VARA uses tricks to reduce the tocall, digi paths, acks, and other things. It balances the slowest speed possible with data length, and the compressed tricks it has hidden within. This is why an uncompressed beacon is more data, but uses a slower speed. It was designed this way to allow the most robust signal and lowest speed with a simple beacon.

  • An uncompressed beacon (no speed or alt) takes 2 VARA packets at speed 1. (~12 seconds)
  • Mic-E beacon with no speed or alt takes 1 VARA packet at speed 2. (speed 1 isn't possible with Mic-E, ~6 seconds)
  • Mic-E with speed and alt is 2 VARA packet at speed 2. (~12 seconds).
  • Compressed with no speed or alt is 1 VARA packet at speed 2 (speed 1 isn't possible with compressed, ~6 seconds)
  • Compressed with speed and alt is 1-2 VARA packets (~6-12 seconds)
  • Some uncompressed beacons WITH comments OR speed and altitude can use speed 1 with 3 VARA packets (~18 seconds)
Every user is different, so how they operate their beacons will greatly vary. So the above should help determine what's best for you speed and time wise, and the air time consideration. Whether you utilize the 1/4 or 1/5 of the air time definitely matters.... but only if the airwaves are actually being used.?

I've been using 30m for 3 weeks 5 days a week or more in the mornings and evenings. I've been the only one mobile during that entire time that I've seen or heard. So what's best practice for my usage and consideration of the network? Easily 2 minute +/- intervals using smart beaconing. There's no problem doing such either. Even if we had a couple other stations, it still wouldn't be a problem. We've tested multiple stations in our 1 year of operations on 40m. It's rare you'll see more than 1 mobile station at any given time.

With that, you are now pointing out a crucial flaw of 30m. The band skips across too much of an area, meaning it could see congestion much quicker. Though unlikely, as basically no one seems to go mobile on the band.

As you said,
"On HF, a reasonable beacon rate is around 15-20 minutes for a mobile, if the channel is being used with multiple users."
I find that just ridiculous unless the band is congested or heavily used. Which is never. So 2-4 minute smart beaconing intervals are perfectly sufficient. Whether on 30m or 40m.

I'm more concerned with the base stations spewing out all the crap "DX" beacons every 30 seconds. Or those who push out the "grid position". Or stations who's messaging is off, but they beacon every 2 minutes with their base station.?

"I think there needs to be some consensus on beacon intervals. I would propose a base station I-Gate beacon on RF at no more than 20 munities intervals. Mobile stations on short trips no more than 4 minutes and long road trips no more than 8 minutes.
?

"As far as the beacon length, I started out with PinPoint with a length of about 20 seconds. I understand PinPoint is not compressed. This may change with a new release. Today I changed to APRSIS32 and the beacon length, which is compressed, is about 10 seconds. I will give this some time to see how this works out."
One problem you're missing here is how VARA works. Compressed or not, it's about the speed when using uncompressed, not the time or length like other packet types. This is why VARA uses speed 1 with uncompressed, because it's specifically designed to use the lowest speed for uncompressed packets. If it didn't, it would use speed 2 exactly like compressed or Mic-E due to the length of data.

So with that, 2-3 minutes and smart beaconing is an acceptable interval WHEN the band isn't being heavily used. Which seems to be never. We adjust as we go, not based on something that isn't happening or never happens.

When stationary (as a mobile), 15-30 minutes is acceptable and best practice. When a base only, 30 is best.

Pinpoint doesn't support smart beaconing, so this requires being a little more diligent with operations and changing it based on how you are travelling.
?


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

On Mon, Jan 20, 2025 at 03:01 PM, Ron Schwartz K2RAS wrote:

I can hear my transmission and the other station's response on a separate HT when running Winlink on the Windows PC. When using the Ubuntu laptop I hear my transmission but the other station simply never responds. Ron

Good to know.? Have you tried Ping and Auto Tune in VARA FM?? My experience is that folks tend to send their audio a little hot which does not help and makes it difficult for the receiving station to decode.
?
Roy Dugger, KD6R


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

That was a really interesting idea, thanks. I can occasionally get a contact through the speakers, but usually not (it seems random, one time it will connect, and the next time not). Very occasionally the sound will cut off for part of a sequence and then continue again. I expect there is still some problem with the sound subsystem in the Ubuntu/WINE installation.

The tones sound identical from each computer. Is there anyone who has successfully gotten VARA FM to work using Ubuntu 24.04 and WINE? Thanks, Ron


Re: Questions on Running 40m VARA APRS mobile

 

Stephen WA8LMF wrote,
"On HF, a reasonable beacon rate is around 15-20 minutes for a mobile, if the channel is being used with multiple users."
?
Hay Stephen on your road trip in October your beacon rate for Vara was about three minutes.
?
I do understand that was a test comparing Vara to AX-25. I am seeing 8 to 15 stations on the 30M Vara channel every day with varying beacon intervals. In addition, the length of the beacon also varies from 10 to over 20 seconds.?
?
I think there needs to be some consensus on beacon intervals. I would propose a base station I-Gate beacon on RF at no more than 20 munities intervals. Mobile stations on short trips no more than 4 minutes and long road trips no more than 8 minutes.
?
As far as the beacon length, I started out with PinPoint with a length of about 20 seconds. I understand PinPoint is not compressed. This may change with a new release. Today I changed to APRSIS32 and the beacon length, which is compressed, is about 10 seconds. I will give this some time to see how this works out.
73
Wayne
WA5LUY
?
?


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

I'm not much of a computer guy so forgive me in advance.
Is it possible that your Ubuntu output has a delay in it before actual audio comes out?
?
Since you have two different machines you could probably test this without transmitting. Instead of running audio through cable, change to you native speakers and mic and put the two machines near each other. One should pick up the others comms and you may begin to notice unique tones missing at the start of each machines chirping. You'll also be able to determine if your problematic machine has an audio-in issue too.
?
Good luck
g


Re: 40M VARA APRS Rocks! (7.083.50 USB)

 

¿ªÔÆÌåÓý

On 1/21/2025 2:12 AM, Bryan KF6NYM via groups.io wrote:
WA8LMF,?Thanks for the great explanation!!?
?
66pacific.com has a mag loop calculator. Looks like a 40M mag loop requires twice the capacitance (121 pF) of a 30M mag loop (59 pF), given the same 20 foot circumference conductor. So, would substituting a 9.06 foot center conductor + dielectric of RG-8 coax make your design resonant on 40M - can you change bands by using a longer center conductor + dielectric of RG-8 coax? Or are other modifications to the antenna necessary?
?
?

?

Yes...? You can tune the loop to any frequency by varying the capacitor value.??? Just note that as you go down in frequency, the capacitance value,?RF voltage and RF current will increase with the inverse square of the frequency if the loop size remains the same.? At the same time, the efficiency of the loop will decrease as the loop becomes a smaller and smaller percent of the natural wavelength.?

Your calculation sounds about right. My values were determined with the "KI6GD Loop Calculator" which used to have it's own website - "magneticloop.com". The site is long gone, but the calculator has been archived on many other sites including here:
???

I have also included the tool?? KI6GD-MagLoopCalc-1.6.exe? in my "Ham Software MegaPak" collection that I sell on 32GB flashdrives at ham fests and radio club meetings.??



Stephen H. Smith??? wa8lmf (at) aol.com
Skype:??????? WA8LMF
EchoLink:? Node #? 14400? [Think bottom of the 2-meter band]
Home Page:?????????

New? 30 Meter?? APRS-over VARA? Frequency
As of 1 Jan 2025.?? Details Here:
????

- APRS over VARA? --
??

"Studio B" Ham Shack on Wheels
??

-
?



Re: 40M VARA APRS Rocks! (7.083.50 USB)

 

WA8LMF,?Thanks for the great explanation!!?
?
66pacific.com has a mag loop calculator. Looks like a 40M mag loop requires twice the capacitance (121 pF) of a 30M mag loop (59 pF), given the same 20 foot circumference conductor. So, would substituting a 9.06 foot center conductor + dielectric of RG-8 coax make your design resonant on 40M - can you change bands by using a longer center conductor + dielectric of RG-8 coax? Or are other modifications to the antenna necessary?
?
?
On Mon, Jan 20, 2025 at 07:59 PM, WA8LMF wrote:

A mag loop is a resonant tuned circuit -- the tubing forms a one-turn coil resonated by a capacitor connected across the open gap.? ?? Normally the capacitor is an external one, often a variable one remotely controlled by a motor. A smaller loop, usually about? 1/5th the diameter of the main loop,? forms the primary winding of an RF transformer to couple RF from the transmitter into the main loop. The main loop is the secondary of the transformer.? The construction of a mag loop is complicated by the immense RF voltages (multiple kilovolts) across the capacitor, and the huge RF currents (10s of RF amps) circulating in the loop at anything above QRP power levels.

In my effort to create the absolutely simplest mag loop for a single frequency, I did away with the external capacitor completely.? The coax+dielectric inserted into the tubing forms one plate of a capacitor. ? The inside surface of the tubing itself forms the other plate of the capacitor.? It just so happened that the inside diameter of 3/8th refrigeration tubing was a perfect fit for the center conductor + dielectric of RG-8 coax.? [Don't use foam dielectric coax like LMR400 or RG-214 - the dielectric which is part polyethylene and part air has a different dielectric constant that causes the capacitance per foot to be different.]

Initially, I inserted enough coax+dielectric into only one side of the loop and soldered the end of the coax conductor to the tubing on the opposite side of the gap.? It worked perfectly to resonate the loop on the first try --BUT-- the immense RF voltage that appears across the capacitor? (3-4 KV at 100 watts) exceeded the breakdown voltage of the dielectric.? The dielectric arced over, melted and scorched with a full 100 watts TX power for more than about 20-30 seconds!? ? (The loop worked perfectly for a QRP FT-817 at 5 watts out, but was useless for a full-power 100-watt HF rig.)

My second pass involved inserting coax into BOTH sides of the tubing, essentially creating two capacitors in series (one on each side of the opening), doubling the breakdown voltage. But two caps in series have half the value of a single cap of the same value.? I worked around this by making each cap twice as large by making the coax section on each side twice as long.??

This modified design (documented in the PDF)? worked successfully and has been on-the-air on 30-meters at 100 watts TX for nearly a decade now. ?

A side benefit is that the 2nd-gen loop is more efficient. ? In a small loop like this, the radiation resistance is a tiny fraction of an ohm, yielding an RF current flow of many 10s of RF amps at the 100-watt power level.?? It is a struggle to get the resistance of any joints in the RF conductor path down to the tiny fraction of an ohm required. ?? It's like high-current 12 VDC power wiring - even a tiny fraction of an ohm of resistance in ring terminal crimps, hose clamps, soldered pipe elbows, etc can lose 1/2 or 2/3rds of the transmitted power.? You wind up heating the joints instead of radiating RF!? I cringe when I see the commercial mag loops made from LMR cable with PL-259 plugs crimped to each end. ?

In my design, there ARE NO joints!? Just a single length of copper conductor with the capacitor inside it. ? Note that to prevent RF arc-over the gap between the two ends of the loop needs to be around a half-inch or greater. ?

?


Stephen H. Smith??? wa8lmf (at) aol.com
Skype:??????? WA8LMF
EchoLink:? Node #? 14400? [Think bottom of the 2-meter band]
Home Page:?????????

New? 30 Meter?? APRS-over VARA? Frequency
As of 1 Jan 2025.?? Details Here:
????

- APRS over VARA? --
??

"Studio B" Ham Shack on Wheels
??

-
?

?


Re: 40M VARA APRS Rocks! (7.083.50 USB)

 

¿ªÔÆÌåÓý

On 1/20/2025 9:57 PM, Bryan KF6NYM via groups.io wrote:
On Wed, Jan 1, 2025 at 06:12 PM, WA8LMF wrote:
WA8LMF, I am going to try building your 30M mag loop antenna. On your website the design is a bit different; the RG-8 center conductor + dielectric is soldered to the copper tubing. It appears the design posted here, the RG-8 center conductor + dielectric is NOT soldered to the copper tubing. I don't understand antenna design well enough to determine how this tuning capacitor is working in each design, would you please explain this aspect of each design? Just want to be sure that I build it correctly. How much capacitance is needed for the design posted here? Thanks!
_

?

A mag loop is a resonant tuned circuit -- the tubing forms a one-turn coil resonated by a capacitor connected across the open gap.? ?? Normally the capacitor is an external one, often a variable one remotely controlled by a motor. A smaller loop, usually about? 1/5th the diameter of the main loop,? forms the primary winding of an RF transformer to couple RF from the transmitter into the main loop. The main loop is the secondary of the transformer.? The construction of a mag loop is complicated by the immense RF voltages (multiple kilovolts) across the capacitor, and the huge RF currents (10s of RF amps) circulating in the loop at anything above QRP power levels.

In my effort to create the absolutely simplest mag loop for a single frequency, I did away with the external capacitor completely.? The coax+dielectric inserted into the tubing forms one plate of a capacitor. ? The inside surface of the tubing itself forms the other plate of the capacitor.? It just so happened that the inside diameter of 3/8th refrigeration tubing was a perfect fit for the center conductor + dielectric of RG-8 coax.? [Don't use foam dielectric coax like LMR400 or RG-214 - the dielectric which is part polyethylene and part air has a different dielectric constant that causes the capacitance per foot to be different.]

Initially, I inserted enough coax+dielectric into only one side of the loop and soldered the end of the coax conductor to the tubing on the opposite side of the gap.? It worked perfectly to resonate the loop on the first try --BUT-- the immense RF voltage that appears across the capacitor? (3-4 KV at 100 watts) exceeded the breakdown voltage of the dielectric.? The dielectric arced over, melted and scorched with a full 100 watts TX power for more than about 20-30 seconds!? ? (The loop worked perfectly for a QRP FT-817 at 5 watts out, but was useless for a full-power 100-watt HF rig.)

My second pass involved inserting coax into BOTH sides of the tubing, essentially creating two capacitors in series (one on each side of the opening), doubling the breakdown voltage. But two caps in series have half the value of a single cap of the same value.? I worked around this by making each cap twice as large by making the coax section on each side twice as long.??

This modified design (documented in the PDF)? worked successfully and has been on-the-air on 30-meters at 100 watts TX for nearly a decade now. ?

A side benefit is that the 2nd-gen loop is more efficient. ? In a small loop like this, the radiation resistance is a tiny fraction of an ohm, yielding an RF current flow of many 10s of RF amps at the 100-watt power level.?? It is a struggle to get the resistance of any joints in the RF conductor path down to the tiny fraction of an ohm required. ?? It's like high-current 12 VDC power wiring - even a tiny fraction of an ohm of resistance in ring terminal crimps, hose clamps, soldered pipe elbows, etc can lose 1/2 or 2/3rds of the transmitted power.? You wind up heating the joints instead of radiating RF!? I cringe when I see the commercial mag loops made from LMR cable with PL-259 plugs crimped to each end. ?

In my design, there ARE NO joints!? Just a single length of copper conductor with the capacitor inside it. ? Note that to prevent RF arc-over the gap between the two ends of the loop needs to be around a half-inch or greater. ?



Stephen H. Smith??? wa8lmf (at) aol.com
Skype:??????? WA8LMF
EchoLink:? Node #? 14400? [Think bottom of the 2-meter band]
Home Page:?????????

New? 30 Meter?? APRS-over VARA? Frequency
As of 1 Jan 2025.?? Details Here:
????

- APRS over VARA? --
??

"Studio B" Ham Shack on Wheels
??

-
?



Re: 40M VARA APRS Rocks! (7.083.50 USB)

 

On Wed, Jan 1, 2025 at 06:12 PM, WA8LMF wrote:
WA8LMF, I am going to try building your 30M mag loop antenna. On your website the design is a bit different; the RG-8 center conductor + dielectric is soldered to the copper tubing. It appears the design posted here, the RG-8 center conductor + dielectric is NOT soldered to the copper tubing. I don't understand antenna design well enough to determine how this tuning capacitor is working in each design, would you please explain this aspect of each design? Just want to be sure that I build it correctly. How much capacitance is needed for the design posted here? Thanks!


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

I did misspeak, the waterfall is on VARA HF (which is working fine). The fact remains, I can hear my transmission and the other station's response on a separate HT when running Winlink and VARA FM on the Windows PC. When using the Ubuntu laptop I hear my transmission but the other station simply never responds. Ron


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

I can hear my transmission and the other station's response on a separate HT when running Winlink on the Windows PC. When using the Ubuntu laptop I hear my transmission but the other station simply never responds. Ron


Re: Questions on Running 40m VARA APRS mobile

 

¿ªÔÆÌåÓý

On 1/20/2025 2:08 PM, Devan Banman via groups.io wrote:
Nice, you could prob go down to 2 min intervals. I do this on my mobile with smart beaconing with varadroid by Mike na7q. Works awesome with the trusdx 4 watts 40m!?
?
?
_.

?

NO!!!?? You can't do that kind of rate on HF!????

1)?? The transmission time is much longer on VARA than on the usual 1200-baud 2M VHF.? A simple beacon, especially if it is not in a compressed format like Mic-E,? can take 20-30 seconds.?? At a two-minute repetition rate, you are occupying 1/5 th to 1/4 of the total capacity of the channel.?

Note that on a random-access channel with no coordinated timing of the users, that if the channel is occupied more than 18-20% of the time, the probability of data collisions between stations goes up sharply. (The so-called Aloha" limit.)


2)?? On two meters, you are occupying the channel over a city or county-sized area. Many users around even a single state can be using the channel at the same time.??

One HF, you are occupying the channel over ONE-THIRD of North America or more.


On HF, a reasonable beacon rate is around 15-20 minutes for a mobile, if the channel is being used with multiple users.



Stephen H. Smith??? wa8lmf (at) aol.com
Skype:??????? WA8LMF
EchoLink:? Node #? 14400? [Think bottom of the 2-meter band]
Home Page:?????????

New? 30 Meter?? APRS-over VARA? Frequency
As of 1 Jan 2025.?? Details Here:
????

- APRS over VARA? --
??

"Studio B" Ham Shack on Wheels
??

-
?



Re: Questions on Running 40m VARA APRS mobile

 

Nice, you could prob go down to 2 min intervals. I do this on my mobile with smart beaconing with varadroid by Mike na7q. Works awesome with the trusdx 4 watts 40m!?
?
?


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

"VARA FM shows signals on the waterfall, "
?
It may have been a mis-written phrase, but VARA FM has no waterfall.? Only the gauges and the constellation diagram.? ? Check to see if you are running VARA FM not VARA HF.
?
Brian - W7OWO??


Re: Transmit Problem on VARA FM Modem Using Ubuntu and WINE

 

Have you monitored the output with a handheld or scanner??
?
Can you hear the response from the other station?
--
Roy Dugger, KD6R