Email the? help? line?

73-G

Hello VARA,

So I finally got my Extra-Class Vanity callsign.

But when I bought VARA I used my former, KD7YZ. So how do I fix the
problem of not being registered with VARA now?


--
Best regards,
Bob NR4U

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Graham,

I'm not sure you are following or fully understand the benefits and costs of ODFM (multiple orthogonal carriers).

Positives:? OFDM Lowers the baud rate which does two things: 1) More energy per bit (power x time) = Joules)

? ...But 2) This? energy must be spread over ALL the active carriers so the Energy per bit decreases with # of carriers.

Negatives:? OFDM creates a higher crest factor(Peak to average value)? of the combined multicarrier waveform.....Higher crest factor means a transmitter of a given PEP rating will not pump out as much (undistorted RF Power).? A pure sine wave has the lowest crest factor.

Ultimately the channel capacity (proposed in 1948 by Claude Shannon and now universally accepted) is defined by the Energy per bit/ Noise bandwidth? (Eb/No).? So the most efficient mode for a PEP limited transmitter is really a single carrier....BUT (part of the no free lunch theorem!) this is not very good at fast data rates (high baud rates) because of multipath distortion (Very common on HF, less on VHF/UHF). (modes like Pactor 4 (HF) use channel compensation/equalization to improve this in poor multipath but it is tricky,more? expensive, and very CPU intensive.)

All hams should strive for a better understanding of these fundamental modes and limits of transmission of data over radio.

73,

Rick Muething, KN6KB

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Thanks. Still want to have you do a presentation for the EOC Comm team & ARES at some point.?

I've had many requests for a specific group in support of DRA Sound Cards, so I created one here at IO.? If you're interested in joining, follow the link (below) or search for "DRA Sound Cards" at IO.

/g/DRA

Kevin W3KKC
Owner

If I may barrow a quote from Star Trek... "Sokath, his eyes open!" I finally understand the relationship. I have seen that chart but could not put 1 and 1 to get 2. Interesting to see 4PSK when I am used to seeing QPSK. Cool,

Thanks guys. I withdraw my request for S/N from the other side. LOL

Thanks
Brian D
KF6BL

Ok Brian,

Depends on which? bandwidth you using , the? modem makes the? best of what's? available?
The number on the? bottom line , indicates which? LEVEL? the? algorithm's have? decided fits the? conditions?
-see the? chart-? Level = Rate?

In terms of robustness , the? more carriers the? better, as the? B/W? increases ,? more? are packed in?
take level 1? ,? 500 Hz / 11 carriers ,? 2300 32 carriers and 2750 40 carriers , note the? RATE stays?
at 18 Bps , so the modem is adding layers of? say??''protection''?

In simplicity , Protection could be Cutting? edge, the? sharper the? knife the? better it? will? cut? [ through the? noise]
so each TX is received? , less chance of? re-tries = maximum transfer rate?

The whole game is? transferring? data from? one side to the? other , with? minimum power and? minimum time?
the? s/n is? only? part of the? jigsaw ,

EG using? chat? with? 500 Hz b/w ,? minimum reported? s/n? looks to be? round?
-22 dB s/n? , that's well? below the noise, but again that's? average value , Im making? qso's with?
USA east coast <> Liverpool on 7 MHz with? 25 watts + vertical Ae , seeing level 1 , 2 , 3 sometimes 4?

73-Graham.

The first part of this is where I try to connect and the last part is when the station connects to me. Using the VARA HF log.
I am using BPQ32 with VARA HF.

Thanks, Graham. I have seen that TX level indicator (as you have ID'd it) but did not understand what it meant. I recognize the data rate but the number in the parenthesis "(x)" was meaningless. Just a number. I have tried to find information about that number and how it relates to signal quality, but have gotten no where. But at least I now know the higher the number the better the link.

Thanks again
Brian D
KF6BL

Brian

The RED graph? shows the? history of the? transfer from your? side of the? link, the? Y axis
is the? Level? / Rate of sending , X axis , shows the? time line?

The in-use TX level is? shown by the number , bottom line of the? App , with the? BPS rate for that? level?

That gives the? sending? station a? visualisation , of the live link , HF qsb? will? cause the? TX Level? to change to? track the??
changing? s/n at the? RX side of the? link , in poor conditions or? low power, the? level will? be in the? low numbers
and the? plot will? display gaps, where the system is attempting to deliver the? last 'frame' or packet?

The s/n is the? average? of the? frame, so the? actual? s/n at any point? along the? time line , may be??
more or less than? the indicated value , not really much use except for? indication ,?

The wanted measurement is the? data? flow rate , as plotted by the? graph?

73-Graham
g0nbd

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Somnetimes wrong command has to do with not being in the same type

P2P is one example.

Some times it is wide and narrow setting.

Check to see if either of these needs to be changed.

I am getting this error and when I connect to a station it connects fine but that is as far as it goes and
disconnects when I look at the log this is what I see any help?

2022-03-29 15:57:14? ? Connecting to W7VQ... 1/15

2022-03-29 15:57:17? ? Connecting to W7VQ... 2/15

2022-03-29 15:57:20? ? Connecting to W7VQ... 3/15

2022-03-29 15:57:23? ? Connecting to W7VQ... 4/15

2022-03-29 15:57:26? ? Connecting to W7VQ... 5/15

2022-03-29 15:57:33? ? Connected to W7VQ? VARA HF v4.6.1

2022-03-29 15:58:42? ? DISCONNECT command received

2022-03-29 15:58:47? ? Disconnected? ? ? TX: 0 Bytes (Max: 0 bps)? ?RX: 0 Bytes (Max: 0 bps)? ?Session Time: 01:14

?

2022-03-29 16:09:56? ? Wrong command: CAPTURE IC7610 (2- USB AUDIO CODEC)

?

2022-03-29 16:09:56? ? Wrong command: PLAYBACK IC7610 (2- USB AUDIO CODEC)

?

2022-03-29 16:12:14? ? Connecting to W7VQ... 1/15

2022-03-29 16:12:17? ? Connecting to W7VQ... 2/15

2022-03-29 16:12:20? ? Connecting to W7VQ... 3/15

2022-03-29 16:12:22? ? Connecting to W7VQ... 4/15

2022-03-29 16:12:25? ? Connecting to W7VQ... 5/15

2022-03-29 16:12:33? ? Connected to W7VQ? VARA HF v4.6.1

2022-03-29 16:14:05? ? QRT Received

2022-03-29 16:14:10? ? Disconnected? ? ? TX: 0 Bytes (Max: 0 bps)? ?RX: 0 Bytes (Max: 0 bps)? ?Session Time: 01:37

?

?

I am getting this error and when I connect to a station it connects fine but that is as far as it goes and
disconnects when I look at the log this is what I see any help?

For Vara FM, you can also "ping" the gateway, and it will respond with the S/N on both ends of the link.



-Scott, NS7C

Thanks, Graham. I'll keep digging into looking for those numbers you are talking about. Appreciate all the help you have offered.

Thanks
Brian D
KF6BL

On Mon, Mar 28, 2022 at 01:43 AM, Brian Donaldson wrote:

VARA with WinLink

Ok Brian

Watch your? Vara app? when? connected ,? the? app? shows the? speed / level its? sending? each frame at? and? the? red plot shows the? sent? data , the? gaps are? re-trys .. so you? have the? info ,?

low? level numbers? and? gaps in the? red plot = poor? s/n / conditions at the? RX?
high level numbers? and? the odd? gaps =? good? ?s/n? at? RX side?

If your? connected? , turn the? power down during? transfer [ up load]? your will? see your? TX level? drop, link slow down? ?and the? number of missed? frames? increase .. too? low and the? modem will? stall , the? RX side will? continue to? request? repeats? till? times? out?

The other side? will? have the? reverse? information

The s/n reported by? VARA is the? 'Average? of the? frame'? ..... the? display? of? dots and lines? , is [in simplicity]? indicating the? % capture of the? frame .??

73-Graham?

Not sure I am following, Graham. I am using VARA with WinLink,not in any other context. The only thing I see is the S/N level on the far right of the program. I have never ventured far from that operation of VARA.

Brian D
KF6BL

On Sun, Mar 27, 2022 at 09:17 PM, Brian Donaldson wrote:

"other" station could report back

Brian?

Its right in front of you -)

The modem selects your? TX? level from the? s/n at the? other side? , that coupled with the? number of? Re-tries you are seeing on your? Tx? gives the over view of the? RX conditions?

So if your seeing your? TX at? level 1? and? multiple re-tries , as plotted by the? RED bar chart , then your? signal is? right down at the? system limit ,
On the other side if your? tx level number is? high and the? Bar plot is? 100%? no? gaps, then your well? inside the? minimum limit
basically the? more power you? run, the? faster the? link will? run , until? you? reach the? maximum TX level and zero re-tries?

The link can be? asymmetric, if your? downloading files, then the? server needs to have? good? s/n ,? you? only need? enough power to? provide the? ack frame?
up-loading, you need? run enough power to minimise connect? time?

In chat ,? other over heads are? exchanged , in a two way? exchange, which are dependant on the? tx/rx levels?

73-Graham?

Ah... so it is not so much VARA that is doing this, but WINLINK. Interesting. That is my primary use, WINLINK EXPRESS. Thanks, Irad, for that info.