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Great info, Mark - thanks!

Orv W6BI

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

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

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

Orv W6BI

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.

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

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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!
??

?

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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!
??

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.

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

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

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

Thanks Mark. This helps clear things up.?

73
Bill

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

Steve

I've used VARA (Winlink, VarAC) on the IC-7300, the IC-7100, the IC-7200, the FT-991A and the FT-891. By far the easiest rig to configure and run with VARA is the IC-7300. The IC-7100 is a close second, but it's no longer in production (a shame, because it really is a great radio). The 7300 is the easiest of all these rigs to configure, it runs cool, the built-in tuner can handle most (but not all) 'mostly resonant' antennas, and the front panel display provides a lot of useful information and access to key options. The radio is such a good fit for digital modes that I own two - one for the shack and one for portable use.

W8BYH