[pskmail] Re: Sailing trip across Atlantic with PSKmail

  • From: John Douyere <vk2eta@xxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Tue, 24 Jan 2012 14:08:05 +1100

Hi Robert,

Great summary and thank you for taking the time to share that experience.

My thoughts and comments, reflecting on what you mentioned:

1. Yes I think there is a steep learning curve when using Pskmail. I think
the key areas are:

a) High range of features tend to confuse users as to what to use when and
how. how can we fix that one?

b) The number of settings we have opened to the user with Fldigi and
Pskmail requiring a fair amount of setup for a newcomer. This is what we
are trying to resolve with the version 2 where the modems are integrated
and therefore can be customized for the application rather than being
generic, limiting the amount of setup required.

Maybe like we see on many applications these days, a "simple mode" and an
"expert mode" in version 2 may make a difference.

c) others???

2. Yes HF is slow but we have be realistic about the laws of nature (or in
that case the Shannon theorem). No amount of mode development will allow us
to download a 1.5Mb picture over a 2.5Khz channel with 100watts at several
1000 KM of distance in 1 minute.

We may gain a factor of 2 or even maybe 4 compared to where we are now, but
that is the order of magnitude of the gains possible with what we have at
hand.

This is why the headers have the total size of the email listed on the
client, together with the from and subject information. So that these large
emails can be ignored during the Pskmail download (postponed until internet
is available).

Alternatively, if the beginning of a large email is of interest, set the
preferences to NOT use compressed email, start the download and stop it
with a STOP command (or worst case an ABORT command). The beginning of the
email will be in the terminal screen.

Plus your idea of adding a warning to the email at the server before
sending it is of interest. This would need to be user-selectable as in some
cases we do not want to add to the original email (like when we use
email-to-sms services for example).

The QSY function is powerful, but again it needs practice to ensure it
works as designed.

If your server is already scanning you don't need to do much (maybe check
the QSY frequency range limits). On the client it is easier to use the QSY
function with a rig control, so that may need a bit of setup.

Great work Robert, with a very useful and practical example.

Best regards,

John

On Tue, Jan 24, 2012 at 11:04 AM, Robert Krasowski <rkrasowski@xxxxxxxxx>wrote:

> Hello everyone.
> When I am writing these  words my friends is docking in Le Marin
> Martinique. Trip is over. They left Canary's Island  on 1/5/2012 and reach
> the destination today 1/23/2012. As a primary mode of communicating we use
> Ham radio. Backup Iridium sat phone was on board but we did not use it even
> once. We use PSKmail for emailing and to get weather information. we used
> PSK APRS for tracking.
>
> Here is equipment that they used:
> Icom 7200
> Antenna tuner : Icom AH4.
> Antenna : Isolated Wire - 33ft from top of the mast to stern.
> Computer : Refurbished Dell D512
> OS : Ubuntu 11.10 (with GNOME classic).
> PSKmail client : jPSKmail 1.5
>
> All equipment worked well, but I am disappointed with the quality of voice
> from Icom 7200. there is some issue with microphone. They have strong
> signal but sometimes I could not understand what they were saying. Sound is
> without high tones and muffed.
>
> There is a steep learning curve with PSKmail. So the advice is to PRACTICE
> before you go. On top of that people who will use it MUST understand the
> limitation of the system. It is SLOW ! We have twice email with 1.5Mb
> picture being send to us.
>
> Over the period of 18 days we exchanged close to 60 emails, total volume
> of about 800kB.
> Over 200 beacon were received by stations from Europe and Americas.
>
> Few problems and majority of this I understand is fixed with new 1.5.4
> version.
>
> What I would change to improve it:
> 1/ E-Mail that is sent from PSKmail station must have info telling not to
> do replay and not to send large files. Also would be nice to use Plain Text
> not a  Rich Text.
>
> 2/ Sometimes it takes long time to receive or send email so doing that
> exchange on "calling frequency" where we have few servers monitoring is not
> a good idea. From what I understand QSY and summon is for that. I need to
> read , understand  and implement it into my server.
>
> Overall I think that trip was a success and clearly showed that PSKmail is
> a great alternative to other way of exchanging emails while sailing.
> Thank to all who work so hard to developed this project.
>
> Best regards
> Robert
> KB2PNM
>
>

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