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Re: Collision avoidance?

 

开云体育

Using G8BPQ software, not uncommon, at 1200 baud AX.25 with NETROM over top of it, the typical 1200 baud throughput is 15 to 25 bytes of payload per second, plus callsigns and flags and whatnot, and that is assuming that PPERSIST is set to some high number, like 200.?

The interesting thing, to me, is what happens when four stations are on the same frequency, attempting two different 1 on 1 conversations, each pair thinking they are alone on the channel. ?

KR3RAL <—> KW1BRB <—> K1DT <—> KE1AST?

KW1BRB in the west suburbs is talking to?KR3RAL, a few miles further out. ? ?
Then later K1DT, in downtown, is talking to KE1AST in the East suburbs.

And then KW1BRB and?KR3RAL?resume. ?But where?K1DT?can hear KW1BRB and KE1AST, the only station KE1AST can hear is?K1DT. ? So?KE1AST?is pinging away trying to get?K1DT?to answer, and?K1DT?is waiting for?KW1BRB to become silent before?K1DT?can transmit. ?Once in a while K1DT sees the channel quiet enough and goes and sends a frame to KE1AST, trashing the frame?KR3RAL?was sending. ? That’s what happens using AX.25. ? What does VARA FM do in this scenario?

The 1200 baud packet exercise, with this scenario, would be massacred pretty badly by bit-errors, plus when a station goes to transmit, it would usually end up waiting until the other stations it can hear are all un-keyed. ?It’s very dynamic. ?If 1200 baud AX.25 is set up with PPERSIST set to a low value on all stations, they’d be really slow in the first place, but the collisions may not be as horrific. ? It’s fun to watch, if one doesn’t take it too personally. ??

The much worse case is when there are a couple of conversations and the stations are using on-channel relays, perhaps more than one relay. ?That’s very common in AX.25 1200 packet. ? The throughput goes from intolerably slow to dropped call.?

I’m a big fan of self-coordinated dedicated point to point link frequencies for VHF or UHF FM data links, where the frequency WIKI has enough channels for people to not be on the same channel as another link within range. ? But this is only useful (in an automated real-time network) if there are more than a couple of radios+modems at each site to cross link the channels. ?See the maps on the ncpacket.net webpage. ?

VARA FM sounds great and I’d love to have something like it that we can build a real-time network out of. ?I wonder how long it will be before one could get a licensed copy in a device that costs under $200 or so, in order that one could build a bunch of multi-port network stations. ?This would put AX.25 to bed finally, maybe? ? ?The $40 NinoTNC on a FM voice radio is good for 2400bits per second, around 40 bytes per second on G8BPQ with PPERSIST=200 and with NETROM taking up time. ?That’s pretty slow compared to what Mark was talking about. ?But a half dozen NinoTNCs can be attached to a G8BPQ network node with half a dozen radios, if one was so motivated. ?In our local network, ncpacket, we have a large percentage of 4800 and 9600 baud capable radios, when matched with a $40 NinoTNC. ?So we’re getting 60 bytes per second to 110 bytes per second on many links. ?But the network stack does not make bit-rate or processing adjustments to compensate for fading links. ?So it gets pretty bad when we have multi-path phasing. ?

We need a network protocol that is more efficient than NETROM, more forgiving of fading links than NETROM, and compatible with VARA FM. ?

I’m partial to the Raspberry PI as a computing platform, but we’ll see how the market for VARA FM compatible embedded solutions develops. ?Using a set of Intel NUCs doesn’t seem completely ridiculous, and getting less and less ridiculous as time goes on? Maybe there is already a better deal than Intel NUC for a single port VARA FM instance of a multi-port node. ??

Tadd KA2DEW in NC. ?https://qrz.com/db/ka2dew ? ? https://ncpacket.net

?

On Jul 27, 2023, at 4:18 PM, Mark Davis <markad7ef@...> wrote:

Orb;

The simple answer is that VARA FM doesn’t do any collision avoidance.

However, when there is an active VARA FM session between two station, any additional stations attempting to connect on the same channel will not see a response from either of the connected stations. Data communications between the connected stations will probably be impaired until the interfering station exhausts its connection retries, but the session normally resumes at that time.

Also, VARA FM supports the busy-channel detection that is implemented in the Winlink Express VARA FM session… if there’s traffic on the channel, the operator trying to connect must click the “Connect Anyway” button.

Keep in mind that the actual best-case?throughput for a single 1200bps connection is on the order of 500bps… under optimal signal conditions. Typical throughput on mildly impaired radio circuits is on the order of 300bps. The per-user throughput is a fraction of that best-case value when multiple users share a channel. This difference between the 1200bps raw data rate and 300-500bps throughput is primarily due to the overhead imposed by the AX.25 protocol.

In contrast, unlicensed VARA FM NARROW throughput is 5Kbps over moderately impaired radio channels where 1200bps packet connections are not even practical. Licensed VARA FM NARROW throughput is at least twice the unlicensed value under similar conditions. Double those numbers again for licensed and unlicensed VARA FM WIDE operation.

Realistically, minimum VARA FM NARROW throughput, for unlicensed use, is 10-15 times higher than single connection 1200bps packet… and 40-60 times higher for licensed VARA FM WIDE operation.

I believe that, compared to 1200bps packet operation, the throughput advantage of VARA FM (WIDE or NARROW), even for unlicensed use, more than makes up the lack of a collision detection.

Mark - AD7EF
Re: Collision avoidance?

 

开云体育

Great info, Mark - thanks!

Orv W6BI

On 7/27/23 13:18, Mark Davis wrote:

Orb;

The simple answer is that VARA FM doesn’t do any collision avoidance.

However, when there is an active VARA FM session between two station, any additional stations attempting to connect on the same channel will not see a response from either of the connected stations. Data communications between the connected stations will probably be impaired until the interfering station exhausts its connection retries, but the session normally resumes at that time.

Also, VARA FM supports the busy-channel detection that is implemented in the Winlink Express VARA FM session… if there’s traffic on the channel, the operator trying to connect must click the “Connect Anyway” button.

Keep in mind that the actual best-case?throughput for a single 1200bps connection is on the order of 500bps… under optimal signal conditions. Typical throughput on mildly impaired radio circuits is on the order of 300bps. The per-user throughput is a fraction of that best-case value when multiple users share a channel. This difference between the 1200bps raw data rate and 300-500bps throughput is primarily due to the overhead imposed by the AX.25 protocol.

In contrast, unlicensed VARA FM NARROW throughput is 5Kbps over moderately impaired radio channels where 1200bps packet connections are not even practical. Licensed VARA FM NARROW throughput is at least twice the unlicensed value under similar conditions. Double those numbers again for licensed and unlicensed VARA FM WIDE operation.

Realistically, minimum VARA FM NARROW throughput, for unlicensed use, is 10-15 times higher than single connection 1200bps packet… and 40-60 times higher for licensed VARA FM WIDE operation.

I believe that, compared to 1200bps packet operation, the throughput advantage of VARA FM (WIDE or NARROW), even for unlicensed use, more than makes up the lack of a collision detection.

Mark - AD7EF
Re: Collision avoidance?

 

Orb;

The simple answer is that VARA FM doesn’t do any collision avoidance.

However, when there is an active VARA FM session between two station, any additional stations attempting to connect on the same channel will not see a response from either of the connected stations. Data communications between the connected stations will probably be impaired until the interfering station exhausts its connection retries, but the session normally resumes at that time.

Also, VARA FM supports the busy-channel detection that is implemented in the Winlink Express VARA FM session… if there’s traffic on the channel, the operator trying to connect must click the “Connect Anyway” button.

Keep in mind that the actual best-case?throughput for a single 1200bps connection is on the order of 500bps… under optimal signal conditions. Typical throughput on mildly impaired radio circuits is on the order of 300bps. The per-user throughput is a fraction of that best-case value when multiple users share a channel. This difference between the 1200bps raw data rate and 300-500bps throughput is primarily due to the overhead imposed by the AX.25 protocol.

In contrast, unlicensed VARA FM NARROW throughput is 5Kbps over moderately impaired radio channels where 1200bps packet connections are not even practical. Licensed VARA FM NARROW throughput is at least twice the unlicensed value under similar conditions. Double those numbers again for licensed and unlicensed VARA FM WIDE operation.

Realistically, minimum VARA FM NARROW throughput, for unlicensed use, is 10-15 times higher than single connection 1200bps packet… and 40-60 times higher for licensed VARA FM WIDE operation.

I believe that, compared to 1200bps packet operation, the throughput advantage of VARA FM (WIDE or NARROW), even for unlicensed use, more than makes up the lack of a collision detection.

Mark - AD7EF
Re: recommendation for HF rig

 

Exactly Mark.

An IC-7000 and a DigiRig can do all of that. (or something like that).

73
Danny, K5CG
HH 550-000-0609
SKCC 14257

From: "Mark Davis" <markad7ef@...>
To: "VARA-MODEM" <[email protected]>
Sent: Thursday, July 27, 2023 2:20:12 PM
Subject: Re: [VARA-MODEM] recommendation for HF rig

While this topic started with a discussion of good radios for VARA HF, several posters commented on the advantages of “all band” (HF + 6M + VHF/UHF) rigs, being able to do VARA FM on VHF/UHF bands.

That’s certainly true, but be aware that the built-in USB Sound-Card system on any of the all-band radios is limited to a 3KHz audio bandwidth. Consequently, when using the built-in USB Sound-Card system, the radio can fully support full-throughput for the VARA FM ‘NARROW’ mode, but you won’t see any better throughput if you switch to ‘WIDE’ mode.

Full throughput VARA FM WIDE operation requires approximately 5KHz audio bandwidth, and a flat frequency-response over that range.

If the all-band radio has a mini-DIN6 “DATA” connector, it’s usually possible to achieve full-throughput VARA FM WIDE connection when using a suitable external USB Sound-Card rig-interface device. The Yaesu FT-991A transceiver is a special case in this regard… that radio has slightly different wiring on the mini-DIN6 connector than what is common practice on almost every VHF/UHF transceiver, and almost every other all-band radio.

Mark - AD7EF

Re: recommendation for HF rig

 

While this topic started with a discussion of good radios for VARA HF, several posters commented on the advantages of “all band” (HF + 6M + VHF/UHF) rigs, being able to do VARA FM on VHF/UHF bands.

That’s certainly true, but be aware that the built-in USB Sound-Card system on any of the all-band radios is limited to a 3KHz audio bandwidth. Consequently, when using the built-in USB Sound-Card system, the radio can fully support full-throughput for the VARA FM ‘NARROW’ mode, but you won’t see any better throughput if you switch to ‘WIDE’ mode.

Full throughput VARA FM WIDE operation requires approximately 5KHz audio bandwidth, and a flat frequency-response over that range.

If the all-band radio has a mini-DIN6 “DATA” connector, it’s usually possible to achieve full-throughput VARA FM WIDE connection when using a suitable external USB Sound-Card rig-interface device. The Yaesu FT-991A transceiver is a special case in this regard… that radio has slightly different wiring on the mini-DIN6 connector than what is common practice on almost every VHF/UHF transceiver, and almost every other all-band radio.

Mark - AD7EF
Re: Collision avoidance?

 

It does not. AX.25 allows for multiple users, Vara is one at a time as far as I know.

KE8GRY

On Thu, Jul 27, 2023, 2:38 PM Orv Beach <orv.beach@...> wrote:
I know how packet radio deals with collision avoidance: poorly. How does
VARA (specifically FM) deal with it?

Orv W6BI
Collision avoidance?

 

I know how packet radio deals with collision avoidance: poorly. How does VARA (specifically FM) deal with it?

Orv W6BI
Re: VARA on M1 Mac

 
Edited

Hello Bill,

I have been running Vara HF on Windows 10 on an i9 macbook pro with 16Mb RAM and now on a Macbook pro M1 10 cores and 16Mb of RAM. All on Parallel with the hypervisor in default config and Windows 11. First of all it works.
Then I can say that it works much better as the i9 was running all fans out with LOG4OM, SDRuno, VaraHF with Winlink or VaraAC and now with the M1 the mac is at 60 - 70 degres and I cannot ear the fans.
I have completed a QSO with Vara AC and Vara HF but not the last version at the time of Vara AC which was not working for me - I have not tried yet the 8.0.6. Will try it soon.
This was in May, I have been travelling then and Windows 11, Parallel and VaraAC have issued new releases since then. At the time VaraAC or HF was freezing when unattended. I have disabled the Parallel Travel mode, but it was still doing it. You could run a QSO but not leave the programs unattended. This is I think a temporary bug which may have been fixed. I will try soon with all the updated versions. There seems to be some power savings kicking in and freezing things. I am also running Cafeine on the Mac to avoid it to go to sleep.
Re: Frustrated, can't get WinLink Vara to talk to IC 7300

 

Thanks,
I do have that driver installed.
Dick

On Thu, Jul 27, 2023 at 7:54?AM WA8LMF via <wa8lmf3=[email protected]> wrote:
On 7/27/2023 9:33 AM, Brian - W7OWO wrote:
Dick,


The 7300 requires a special Serial Port driver. Hopefully you have already installed it before plugging the radio's USB cable to the computer, as Windows will load a driver that won't work for you? If not you will need to down load it from ICOM's website ()?and follow the installation instructions they provide

?

There is nothing "special" about this driver!?

It is a six-year-old version of the standard driver for the Silicon Labs (a,k.a. "Silabs") CP-210x? chip used in many USB<-->serial "dongles". ? It is widely used by all three major Japanese radio mfrs (Kenwood, Yaesu and Icom) for serial-over-USB memory programming, CAT controls and sound card PTT keying.


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

"Studio B" Ham Shack on Wheels
??

APRS over FLdigi Modes? --
??

60-Meter APRS!?? HF NVIS APRS Igate Now Operating
??

Flying Digipeater!
??



Re: Frustrated, can't get WinLink Vara to talk to IC 7300

 

Thank you.
I have installed the Icom driver for ports.
Also, I discovered Windows 11 Sound Settings has a line "More settings". When you click that it takes you to the familiar settings for the CODEC stuff.

That said, I still can't get to the Radio settings to tell it I have an IC 7300. I know that it should show up right after I click Open Session. It doesn't. It does open the Vara screen with the round gauges, which is sitting down on the task bar.

Dick

On Thu, Jul 27, 2023 at 6:33?AM Brian - W7OWO <W7OWO@...> wrote:
Dick,

The Radio Configuration is a menu under the Settings?menu of the VARA HF WInlink Session Window, the VARA HF window only manages the Sound Card.

The 7300 requires a special Serial Port driver. Hopefully you have already installed it before plugging the radio's USB cable to the computer, as Windows will load a driver that won't work for you? If not you will need to down load it from ICOM's website ()?and follow the installation instructions they provide? ().? I have found them to be rather thorough.? The first steps you will need to follow is the part about uninstalling the driver that Windows loaded.??

Brian - W7OWO

Re: VARA on M1 Mac

 

On Thu, Jul 27, 2023 at 06:03 AM, N3CNO - Nick wrote:
Do you know if anyone is working on VARA HF or VARA FM modem programs that will run natively on Macs?
Nick;

The VARA HF and VARA FM radio-modem software is proprietary. It is entirely up to the developer, Jose Alberto Nieto Ros EA5HVK, whether to develop versions that run natively under operating systems other than Windows.?

If Jose did decide to produce versions of these programs that ran natively on Apple Mac computers, he'd probably have to seriously consider rewriting the signal-processing code using ARM development tools, so that these vital functions would run with maximum efficiency on the M1 processors.

While the VARA programs are, essentially, "radio-modems", and are of limited use by themselves, they are essential for the operation of higher level radio-email and radio-chat programs, the most popular of which are Winlink Express and VARAC.

Unfortunately, Winlink Express and VARAC are currently Windows-only programs.

It's a "chicken and egg" situation... until there's a reasonable base of MacOS native radio-email and radio-chat programs, there's little impetus for Jose to develop native Mac VARA programs, and until Jose develops native Mac VARA programs, there's little impetus for the developers of radio-email and radio-chat programs to produce native Mac versions of those programs.

Mark - AD7EF
Re: recommendation for HF rig

 

I have a lot of rigs. Receive audio is really important to me and a characteristic of the best radios. My IC-7300 is easy to use, but its?receive audio is inferior to nearly every rig in my shack. My Kenwood TS-690s is an old rig, but the receive audio is great.?

If you want a rig with digital capabilities built-in, then the 7300 is a relatively inexpensive option - but maybe wait and see if there are other recommendations regarding audio quality.

Good luck 73
Mark 4x1ks

On Thu, Jul 27, 2023 at 6:15?PM WA8LMF via <wa8lmf3=[email protected]> wrote:
On 7/27/2023 10:43 AM, Phil Cornell w7plc@... wrote:
I use a FT-991A.? The IC-7300 is a great radio but I like the 991A for it's coverage.? The 7300 is HF+6, the 991A is HF+6+VHF+UHF.? This means that I can run a VARA HF session and with just a few menu changes, I can be running VARA FM in minutes.? This is a great EMCOMM radio, one power source, one radio, 2 antennas.

Re: recommendation for HF rig

 

开云体育

On 7/27/2023 10:43 AM, Phil Cornell w7plc@... wrote:
I use a FT-991A.? The IC-7300 is a great radio but I like the 991A for it's coverage.? The 7300 is HF+6, the 991A is HF+6+VHF+UHF.? This means that I can run a VARA HF session and with just a few menu changes, I can be running VARA FM in minutes.? This is a great EMCOMM radio, one power source, one radio, 2 antennas.
_._,_._,_


A couple of comments about the FT-991...

1)?? I almost choose an FT-991 for my ham shack on wheels a.k.a. "Studio B" (see link in sig line below) for it's multi-band? multi-mode? flexibility and USB-connected internal "sound card". ?? I was then put off by it's high DC power drain -? almost 3 amps at 12 VDC on RECEIVE! . This is (to me) a major issue for battery/solar power systems in the field.? I finally went with my venerable Yaesu FT-857 that draws only 750mA on receive and covers the same bands with the same two antenna ports.?

The FT-857 with the optional 500 Hz CW mechanical filter enabled in the USB or HF DATA mode is an excellent performer on VARA HF narrow mode. ??


2)?? The built-in sound card of the FT-991 does not have enough audio bandwidth to pass VARA-FM FAST mode.? You have to use an external sound card / interface like a Masters DRA, DigiRIG, etc connected to the FT-991's 6-pin mini-DIN data port for VARA FM FAST.


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

"Studio B" Ham Shack/micro-EOC on Wheels
??

-- APRS over FLdigi Modes? --
??

60-Meter APRS!?? HF NVIS APRS Igate Now Operating
??

Flying Digipeater!
??


?
Re: Frustrated, can't get WinLink Vara to talk to IC 7300

 

开云体育

On 7/27/2023 9:33 AM, Brian - W7OWO wrote:
Dick,


The 7300 requires a special Serial Port driver. Hopefully you have already installed it before plugging the radio's USB cable to the computer, as Windows will load a driver that won't work for you? If not you will need to down load it from ICOM's website ()?and follow the installation instructions they provide

?

There is nothing "special" about this driver!?

It is a six-year-old version of the standard driver for the Silicon Labs (a,k.a. "Silabs") CP-210x? chip used in many USB<-->serial "dongles". ? It is widely used by all three major Japanese radio mfrs (Kenwood, Yaesu and Icom) for serial-over-USB memory programming, CAT controls and sound card PTT keying.


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

"Studio B" Ham Shack on Wheels
??

APRS over FLdigi Modes? --
??

60-Meter APRS!?? HF NVIS APRS Igate Now Operating
??

Flying Digipeater!
??



Re: recommendation for HF rig

 

I use a FT-991A.? The IC-7300 is a great radio but I like the 991A for it's coverage.? The 7300 is HF+6, the 991A is HF+6+VHF+UHF.? This means that I can run a VARA HF session and with just a few menu changes, I can be running VARA FM in minutes.? This is a great EMCOMM radio, one power source, one radio, 2 antennas.
Re: Frustrated, can't get WinLink Vara to talk to IC 7300

 

Dick,

The Radio Configuration is a menu under the Settings?menu of the VARA HF WInlink Session Window, the VARA HF window only manages the Sound Card.

The 7300 requires a special Serial Port driver. Hopefully you have already installed it before plugging the radio's USB cable to the computer, as Windows will load a driver that won't work for you? If not you will need to down load it from ICOM's website ()?and follow the installation instructions they provide? ().? I have found them to be rather thorough.? The first steps you will need to follow is the part about uninstalling the driver that Windows loaded.??

Brian - W7OWO
Re: Frustrated, can't get WinLink Vara to talk to IC 7300

 

Check your sound card settings.? For me WIN11 removed all my sound card settings.? I even think i had to reload the Icom drivers.? Steve N4RAF
Re: VARA on M1 Mac

 

Mark,

Do you know if anyone is working on VARA HF or VARA FM modem programs that will run natively on Macs? ?This will be a huge game changer for Apple users. ?Many ham radio applications are now being built for Macs and iOS. ?It would be great if VARA caught up.

73,
Nick N3CNO
Re: VARA on M1 Mac

 

Thanks Mark. This helps clear things up.?


73
Bill
Re: recommendation for HF rig

Steve Fox KA4FOX
 

Find a nice used 7100. VARA FM and VARA HF in one easy to use box.

Steve
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