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There has been considerable discussion of the
relative merits of APRS-over-VARA on 30 meters vs 40 meters
recently on several mailing lists.???
On February 8th, I will be traveling from my
home QTH in central Michigan (Meridian Twp east of East Lansing)
to Traverse City, MI for the annual Cherryland Amateur Radio
Club? Swap-N-Shop. This is about a two-hundred mile (360 Km)
drive.
I plan to conduct a test of 30M vs 40M
APRS-over-VARA on this trip. I have TWO HF rigs in the car with
separate antennas. One is a Yaesu FT-891 with a mono-band
hamstick on a fender split-ball mount, dedicated full-time to
30M HF APRS. The other is a Yaesu FT-857 with an ATAS-120A
screwdriver antenna? hard-mounted to the trunk lid is used for
general operating on bands other than 30M -- usually for my
"Mobile SSTV LiveCAM" on 15 or 10 meters. ?
For this trip, I will put the 857 and ATAS-120
on 40 meters APRS.? I will run two instances of UIview, two
instances of the VARA-HF modem, and two interfaces on the mobile
laptop, one for 30 meters and one for 40 meters side-by-side.?
The Panasonic Toughbook CF-53 quad-core computer with 16GB RAM
has no trouble running all this,? along with a third instance of
UIview for two-meter packet APRS on my Kenwood TM-D700.
The departure to the ham fest will be in
darkness around 3:00 AM local (Eastern) time, so as to arrive at
the venue by 7:30 AM (around sunrise) in time to setup.? The
return trip will be in full daylight, problably starting around
1:30 PM local.??
As in previous packet vs VARA tests, I will be
using different SSIDs for the 30 and 40 meter beacons --
WA8LMF-2 for 30 meters and WA8LMF-3 for 40 meters so one will
able to generate different tracks on APRS-fi for the two bands.?
WA8LMF (no SSID) is always my two-meters FM + internet beacons.
This trip will probably be in the skip zone
for my own igate in central MI (once I get out of town) on 30
meters, and probably also on 40. I will be depending on other's
igates on both bands to reach the Internet on HF.?
Any thoughts about this before I set out next
month??
I'm already planning to do this also on next
summer's annual road trip to Evergreen Colorado for the
Evergreen Jazz Festival always the last weekend? of July. This
will involve full-summer long-days HF propagation on both
bands.?
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
??
-
?
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I'm certainly excited about this! I love seeing this kind of stuff!
I would say based on your specific location the results will be uniquely balanced in some ways... Here's my guess, assuming no sun explosions, and assuming you'll host your own IGates, which wasn't fully clarified.
40M Night: Given a good antenna and ground plane, at night, I would expect you'd get out well on 40M to the western US where most of us with permanent stations are located. So I figure that track will be quite nice with the large number of IGates out our way. If you have your own IGate on 40M at home, you'll be in the skip zone, too close to use it, or any other that might be within close proximity of your region
40M Day:?I would expect that during the day hours, if you have your own IGate at home, that the track would be perfect if within the NVIS zone. Which is typically 0-500 miles. Since there's no skip zone during the day, this makes it most ideal and predictable. Given you have a good ground place and this IGate, it'll be perfect. Especially if other IGates are within range.
30M Night: I'm thinking the night tracking will be less than favorable, as propagation is very unpredictable this high in frequency during the night time. There is also a lot of skip.
?
30M Day:?Propagation on 30M during the day is certainly more predictable. I expect that your home station *may* receive you for part of the trip, but 30M has a skip zone and very little NVIS. So you'll probably rely more on the distant IGates than your own. But you'll see a nice balance between the 2 is my guess.
I expect that 40M will have a near perfect track day and night, and given you have your own IGate for the day trip because the east coast lacks ham operators it seems. 30M will give a reasonable track during the day, but the night is what I question the most! I don't expect the night track to be good once you pull out of the home coverage after some miles.?
How did I base my data??
On the west coast and midwest, we've had a number of stations do day and night mobile tracks. They were always perfect given they had a good antenna. As well as given they have a day station within 500 miles of them, and a night station greater than 500 miles from them. The west and part of the midwest has all of those stations.
I have done tests on 40m multiple times around the clock at all hours driving for full days and full nights. Those were always the results. Based on tracking others stations, the same results are achieved. As seen by all of our IGate and RF stations as well.
As for 30M. When RF stations or IGates are seen on 30M, we see good conditions during the day that are pretty predictable. At night, it seems more often than not, that most stations are not gated, because the skip is unpredictable and not favorable.?
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On 1/3/2025 6:59 PM, Michael - NA7Q via
groups.io wrote:
I'm certainly excited about this! I love seeing this kind of
stuff!
I would say based on your specific location the results will be
uniquely balanced in some ways... Here's my guess, assuming no
sun explosions, and assuming you'll host your own IGates, which
wasn't fully clarified.
?
I expect that 40M will have a near perfect track day and night,
and given you have your own IGate for the day trip because the
east coast lacks ham operators it seems. 30M will give a
reasonable track during the day, but the night is what I
question the most! I don't expect the night track to be good
once you pull out of the home coverage after some miles.
My experience with my home igate/beacons located at 42 44.54
NORTH is that 30 meters almost always has a minimum skip zone in
this part of the world of 250-300 miles (400-480 Km) day or
night.? When I head out in my own mobile, I normally don't start
seeing my home station (70 watts into homebrew magloop) until I
get to Chicago, Cincinnati, or Toronto. Normally during my APRS
demos at Dayton from my radio trailer, I normally don't see my
home station on 30M at all. ? This was with conventional packet
APRS.? On a recent trip to my sister's farm in Kalamazoo (about 80
mi (130 Km) south-west of here, I was surprised that I WAS hearing
my home station on 30m APRS-over-VARA.?? I suspect the approx 15
dB advantage of VARA over AX.25 packet was allowing me to hear
very weak backscatter propagatiion on 30 meters.
This is why I have been experimenting with APRS on 60-meters,
where you have guaranteed? 0-300 mile NVIS propagation nearly
24/7.
I haven't really checked out the purported NVIS? 0-300 range on
40 meters. At night here in central Michigan, the nearest stations
I normally hear on SSB and SSTV are in the upper South (Tennessee,
Virginia, and North Carolina). ?
I've been monitoring 40M APRS-over-VARA on 7083.5 USB for the
last several days, since the 40M APRS discussion erupted on this
list.? I'm using a Yaesu FT-818 porta-luggie with a 500 Hz Collins
IF filter into my G5RV.? ? So far I am hearing far fewer stations
than on the newly-established 30M APRS-over-VARA frequency of
10.148.200 MHz USB.? But then we just got hit with another solar
storm (Northern lights visible at my latitude.) I start seeing the
west coast stations about 2200-2230 local Eastern time (0300-0330
UTC).?? I won't really get a sense for what 40M can do, until I
give it a week or so to see what happens.
By the way, I do have igates running 24/7 on 30 meters, both for
300-baud AX.25 and for VARA. ? I will run an igate with the FT-818
on 40 meters for the road trip test.? (Or what we call "drive
tests" in land-mobile and cellular systems engineering.)
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
??
-
?
How did I base my data??
On the west coast and midwest, we've had a number of
stations do day and night mobile tracks. They were always
perfect given they had a good antenna. As well as given they
have a day station within 500 miles of them, and a night station
greater than 500 miles from them. The west and part of the
midwest has all of those stations.
I have done tests on 40m multiple times around the clock at all
hours driving for full days and full nights. Those were always
the results. Based on tracking others stations, the same results
are achieved. As seen by all of our IGate and RF stations as
well.
As for 30M. When RF stations or IGates are seen on 30M, we see
good conditions during the day that are pretty predictable. At
night, it seems more often than not, that most stations are not
gated, because the skip is unpredictable and not favorable.?
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Let's wait to see real data rather than broadcasting one operator's confirmation bias.
73 de K3FZT / Steve --
Steve Davidson K3FZT | GMRS: WRVS468Winlink Gateway K3FZT-10@...?direct or via W3EOC-3 Supporting VARA FM Wide/1200bd Packet WIRES-X Room #85218 "MARC-DARBY" 444.050 mHz
On Fri, Jan 3, 2025 at 6:59?PM Michael - NA7Q via <mike.ph4= [email protected]> wrote: I'm certainly excited about this! I love seeing this kind of stuff!
I would say based on your specific location the results will be uniquely balanced in some ways... Here's my guess, assuming no sun explosions, and assuming you'll host your own IGates, which wasn't fully clarified.
40M Night: Given a good antenna and ground plane, at night, I would expect you'd get out well on 40M to the western US where most of us with permanent stations are located. So I figure that track will be quite nice with the large number of IGates out our way. If you have your own IGate on 40M at home, you'll be in the skip zone, too close to use it, or any other that might be within close proximity of your region
40M Day:?I would expect that during the day hours, if you have your own IGate at home, that the track would be perfect if within the NVIS zone. Which is typically 0-500 miles. Since there's no skip zone during the day, this makes it most ideal and predictable. Given you have a good ground place and this IGate, it'll be perfect. Especially if other IGates are within range.
30M Night: I'm thinking the night tracking will be less than favorable, as propagation is very unpredictable this high in frequency during the night time. There is also a lot of skip.
?
30M Day:?Propagation on 30M during the day is certainly more predictable. I expect that your home station *may* receive you for part of the trip, but 30M has a skip zone and very little NVIS. So you'll probably rely more on the distant IGates than your own. But you'll see a nice balance between the 2 is my guess.
I expect that 40M will have a near perfect track day and night, and given you have your own IGate for the day trip because the east coast lacks ham operators it seems. 30M will give a reasonable track during the day, but the night is what I question the most! I don't expect the night track to be good once you pull out of the home coverage after some miles.?
How did I base my data??
On the west coast and midwest, we've had a number of stations do day and night mobile tracks. They were always perfect given they had a good antenna. As well as given they have a day station within 500 miles of them, and a night station greater than 500 miles from them. The west and part of the midwest has all of those stations.
I have done tests on 40m multiple times around the clock at all hours driving for full days and full nights. Those were always the results. Based on tracking others stations, the same results are achieved. As seen by all of our IGate and RF stations as well.
As for 30M. When RF stations or IGates are seen on 30M, we see good conditions during the day that are pretty predictable. At night, it seems more often than not, that most stations are not gated, because the skip is unpredictable and not favorable.?
--
73 de K3FZT / Steve
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Hi Steve, there's no bias per say. It's all based on over a year of testing and experimenting. We started testing around October of 2023 on every band day and night. By December of 2023 we had a fully established network on 40m, as nothing else compared to the reliability and coverage.
?
We didn't establish our network to DX, we did it to be able to communicate and operate as we do on VHF APRS. What a success it has been! Our data doesn't lie, and it definitely isn't biased, because it's data...
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Here's 1200 miles of track. I'd call this data, not bias. I have plenty more of this where that came from.
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I'm not a hot shot scientist, but I've authored peer-reviewed science and read and taught plenty of it for 40+ years.
There's always bias as science and even quality evaluation are human endeavors.
I'm not questioning your data.
I want to see Stephen's WA8LMF's data as do you.
However, by writing what you did--what you expect to see in his yet to be collected data--you have shared not only your own likely confirmation bias, but you have set the stage for every reader of your message to bring your bias to their individual interpretation of the data when it's presented along with results and conclusions derived therefrom.
Better data scientists and authoritative scientific journal editors than I have demonstrated this to be the case.
I have no problem with you celebrating your results.?
Predicting another's results based on your results sets the stage for confirmation bias among viewers and interpreters of the subsequent results and is generally avoided unless explicitly part of the null hypothesis statement of a randomized trial--not what is happening here.
Regards to you, Michael, and the list.
73 de K3FZT / Steve --
Steve Davidson K3FZT | GMRS: WRVS468Winlink Gateway K3FZT-10@...?direct or via W3EOC-3 Supporting VARA FM Wide/1200bd Packet WIRES-X Room #85218 "MARC-DARBY" 444.050 mHz
On Sat, Jan 4, 2025 at 10:21?AM Michael - NA7Q via <mike.ph4= [email protected]> wrote: Hi Steve, there's no bias per say. It's all based on over a year of testing and experimenting. We started testing around October of 2023 on every band day and night. By December of 2023 we had a fully established network on 40m, as nothing else compared to the reliability and coverage.
?
We didn't establish our network to DX, we did it to be able to communicate and operate as we do on VHF APRS. What a success it has been! Our data doesn't lie, and it definitely isn't biased, because it's data...
--
73 de K3FZT / Steve
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It's not exclusively MY results. It's the results of around 30 people in 2 months time when we first started VARA APRS, AND the tests of 40M within over a years time.
Which also includes random tests outside of 40M within that years time by our group. We've even taken the last week to try 30M with nothing but results closer to 0% success.
Sounds to me like you're over analyzing the statements and making assumptions. This is all about performance, not bias.
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Stay well 'cause life is beautiful.
73 de K3FZT / Steve --
Steve Davidson K3FZT | GMRS: WRVS468Winlink Gateway K3FZT-10@...?direct or via W3EOC-3 Supporting VARA FM Wide/1200bd Packet WIRES-X Room #85218 "MARC-DARBY" 444.050 mHz
On Sat, Jan 4, 2025 at 2:20?PM Michael - NA7Q via <mike.ph4= [email protected]> wrote: It's not exclusively MY results. It's the results of around 30 people in 2 months time when we first started VARA APRS, AND the tests of 40M within over a years time.
Which also includes random tests outside of 40M within that years time by our group. We've even taken the last week to try 30M with nothing but results closer to 0% success.
Sounds to me like you're over analyzing the statements and making assumptions. This is all about performance, not bias.
--
73 de K3FZT / Steve
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I gotta say, today is the first time in a long time I've had 30m working! NVIS is working a little bit too with it. Even within a short distance! There's a lot of fluctuation though. As much as 14db of it. Only one station heard so far. Hearing quite a few on 40 though.
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I have to agree with Steve K3FZT on his confirmation bias point. ?When you enter an experiment to test a hypothesis, regardless of how much prior study evidence has preceded that experiment, any researcher bias usually enters into the experiment which can go so far as to influence the construction of the testing method all the way to the analysis of the resulting evidence.? For the researcher to express that bias from the outset poisons the results in the minds hearing/reading it to some degree.? And goes against the grain of science philosophy.? How can we now trust that this test is now constructed properly, then conducted properly, and then results accurately/completely reported? ? I personally have not yet setup VARA APRS HF, but am strongly interested in it.? Therefore, OBJECTIVE research evidence is of great interest to me before I plunk down the initial $$ and time/effort to pursue it.? My bet is that there are many others here on this list who feel the same.? I could be wrong, tho, as I have run into some hams who don’t care about $$, their time, and hold their own prejudices about many topics.? Now I’m hoping testers (can there be more than one, please?) of this comparison can do a good job of putting aside prejudice and concentrate on making a test methodology that provides a fair comparison and an accurate/complete reporting of test results. ? Stephen W9SK (from WA, now in NC) ?
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From: [email protected] < [email protected]> On Behalf Of Michael - NA7Q via groups.io Sent: Saturday, January 04, 2025 2:20 PM To: [email protected]Subject: Re: [VARA-MODEM] 30-meters vs 40-meters APRS-over-VARA Shootout Coming ? It's not exclusively MY results. It's the results of around 30 people in 2 months time when we first started VARA APRS, AND the tests of 40M within over a years time.
Which also includes random tests outside of 40M within that years time by our group. We've even taken the last week to try 30M with nothing but results closer to 0% success.
Sounds to me like you're over analyzing the statements and making assumptions. This is all about performance, not bias.
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You guys are quite funny honestly. This is ham radio, not some "science" experiment based on your feelings. Take or leave it. We're out here having fun either way with our big group.
After a few hours on 30m, I heard a few folks, but could only get a message to one of them. Big gun WA7GMX. He's always got a big signal on 40m at <100 miles away. 30m with him is usually a challenge to work, but not today. The band is doing interesting things today, so he's anywhere between -1 and +14.?
The other stations I heard I had no luck reaching with a "ping" message.?
Speaking of ping, if you ever see my home station NA7Q-1, you can send me a message of "ping", and it will return a message with your S/N report from VARA. Very handy tool to see what your signal is compared to what you heard from a station.
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Steve K3FZT
Stephen W9SK