pa0r

It is done. The next release of the PSKmail client will offer the possibility to use Evolution (or PINE, or Mutt, Mailx etc.) as a mail integrator. PSkmail has a menu item 'send mail to mbox',  and when you click on 'get mail' in Evolution the emails you just downloaded with PSkmail are integrated in the mail client. You can do this off-line, PSKmail does not have to run to do this.

The mail send facility works even easier. You write your email in Evolution (reply, forward, address book, all the bells and whistles) and push the send button, as if you are connected to the internet. Evolution will hand the mail over to Postfix, which is the send mail client in most Linux distro's. As your machine is not connected to the net, Postfix will put the mail into the 'deferred' queue.

A cron job (running as root) which runs every 5 minutes picks up the stuff in the outgoing mail queue, reformats (simplifies) it for pskmail and delivers it to the pskmail send queue... All but the necessary (To:, Subject:) headers are stripped, to adapt the format to the 70wpm pskmail data stream. The headers are added back by the pskmail server, which has the necessary data in its user database.

Now you just connect to the pskmail server, push the send button, and off you go... After receiving the "Message sent" from the server the email is deleted from the queue (after adding a copy to the 'Sent' file).

This adds quite a bit of comfort. Of course "There Is More Than One Way To Do It" in pskmail. There is still the 'NEW' routine to write a fast email message without starting Evolution, or you could simply send a single line APRS email message ("We have a new cat")  from the command line....

The next release is due when I get back from our sunny spot in Spain, until then I will be the only one to enjoy this :)

EA/PA0R/P

Since yesterday I can read my PSK mail using Evolution, or with the standard UNIX 'Mail' client (and of course with all mail readers that use the mbox file standard. Here is a pic...

There is a heated debate going on over which is the best digital mode. This debate gets fuzzier and louder every time a new mode is introduced. Those new modes always have more carriers, larger bandwidth and doubtful increases in performance.

This increase in performance is argued to be the very thin line between copy and no copy. The differences are measured in dB with reference to the noise floor, and for some the throughput speed of the system is the main cryterion. Meanwhile, the appliance operators (is your MixW version up to date?) cannot wait to apply the new mode and whine about not being able to tell them apart in their waterfall anymore. Yes, we are now turning the waterfall into some sort of TV where the 90% clueless can actually read with their own eyes that this is a PSK31 signal! I am amost certain I will witness the day when voice output will be added ("You are looking at a PSK31 signal, courtesy of the Microsoft Company"). (Sorry for that one, but I had to...)

Now you could argue about what is copy, and what not. And when have you last heard the noise floor in the digital portion of the band? In person-to-person communication we are used to signals with holes in them because of QSB or QRM. That's why we have learnt to repeat the most important information ("My name is Xilantriugharius, I spell X, i, l, ...). This has been practise since the advent of ham radio, and at least my generation thinks this is perfectly normal.

As soon as the machines (RTTY, TOR) took over the generation of the signal stream, and the operator did not get tired anymore when a long message had to be sent, as his brain did not have to do the de'coding', some clever people though that it might be advantageous to send everything twice, as a preventive measure. This marked the birth of FEC. FEC was used in one-tx-to-many-rx messages, the so-called bulletins. In station-to-station communication, however, not FEC was used but ARQ.

The difference between ARQ and FEC is simple. FEC allows to reduce the number of errors generated at the receiving end, and ARQ allows to kill them completely. For bulletins ARQ is not possible because you need 2 concrete entities for it, and bulletins have many receivers which would create chaos. The interesting thing about it is that when ARQ is used in a clever way it  has a lot less overhead than FEC, and wastes less power per symbol. Which is a nice contribution to ecology.

In other words, FEC is just a stop-gap which should be used in situations where ARQ is not possible.

Now, why is it that all these new fancy, qrm generating bandwidth eating modes are conceived? I think it is an outcome of the primitive way the male brain works. If more developers were women, you would have more emphasis on intelligent solutions than on 'wider, bigger, stronger', in other words the brute force method. I know that a lot of people are very much in favour of the bulldozer approach, but could we plase do it outside of ham radio?

OFDM modes work after the principle of: 'when you qrm one of my frequencies, I will transmit simultaneously on two frequencies'.  And 'when you qrm 8 of my frequencies' I will transmit on 8 more frequencies. 'And moreover, I will make sure I  transmit everything twice, 4 times or whatever I need to get the message through'. All this sounds very much like war to me. And frankly, some days I have the feeling I am already in the middle of one.

Now, as the free lunch (TM) is still 'pie in the sky', all these simultaneous carriers and send-twice-with-a-time-gap need lots of power (the larger the bandwidth and the length of the message, the more power), and all the unnecessary redundancy produces a lot of qrm on our crowded bands.

ARQ, however works more like the radio operator every large ship or airplane used to have - when they could still afford them. If some part of the message does not come through, it can ask for repeat of just that part... If my single carrier is knocked out for 10 seconds because of qsb, it will repeat just the part which was missing. And if my single carrier is suddenly disappearing because a bloating OFDM signal comes on top of me the ARQ system can wait until the brag tape is sent, and pick it up from there...

And now an easy puzzle: If it takes 20 Watts to produce an S9 signal with 1 carrier, how much power do you need for 16 carriers? Or 64?

Now let's see... if I am 5 carriers above the noise floor...

One of the things you can do with pskmail is search Google. Just open the webpage interface and enter:

http://www.google.com/search?q=searchphrase

where 'searchphrase'is anything you had always wanted to know', but never dared to ask....

Tnx Per, SM0RWO for this info!!

I am sure this will get us into the "Guinness Book Of Records" for supplying the slowest Google interface without using an internet connection.

Congratulations to Per, SM0RWO who decoded the callsign of the pregnant sea cow which has been haunting the 30 meters frequency where we carry out our pskmail and aprs experiments. It turned out to be one of the gateways on the APRS net on 30 meters...

Per, the beer (a famous Belgian Brand) is yours!!

Now, the transport problem...

I have just discovered the time leak effect. After the gas leak, the fresh water leak, the oil pipeline leak and the famous memory leak (what?? you still program in C++?) the time leak is one of the the biggest nuisances you can come across.  We have to fight it on a daily basis  here (we are still in Spain, and the sun is rewarding us for it every day now).

When I still had to work for someone else there was no such thing. You had your diary and your local time on the Palm, and except for the days when you were 'completely interrupt driven', you followed the path your secretary had written into your machine, and in the end your boss was happy, you were happy and your xyl was reasonably happy. Especially when you were away for a contest weekend. And you had the feeling time did not exist,it was just a figure (8 divided by 15) on the front page of your Palm (TM).

Now that I do my own planning there seems to be a constant lack of time. The xyl is of the opinion that my planning skills are not on par with what I try to achieve, but it must be something else. When we drove down to the South of Europe I had a todo list for tlf and for PSKmail. I also wanted to write a database program (in PERL of course) for the locations we can park the camper for a free overnight stay, so I can feed them into gpsdrive. It was a waste of time. The planning that is...

Until now I have spent all my time on testing pskmail. Writing additions and changing stuff so it works even better. This camp ground is an excellent test bed for the program. I am 2200 km from the server and the internet facility (4 old desktop computers with W98 of which 3 are constantly out of service because some virus has to be removed) is in use all the time. At least at the occasions when you could fit in into your planning.

The pskmail link to Stockholm works all day. From 8:00 UTC (no use getting out of bed early because the bread shop is not open before that time) until sometimes 22:00 UTC. During mail sessions I use 80 Watts and in between my APRS beacon roars along with 20 Watts input. If the computer is not in use for something else :)

Then we have to go shopping. There are 3 supermarkets in walking distance, so we tend to buy a lot of stuff which I have to carry back to the camper (a bottle of good wine weighs just short of 1 kilogram). Then we have to go walk on the fantastic beach, and watch the sand castle artist rebuild his castle which has been ruined by the dogs during the previous evening. Then we've got to have lunch, mostly sitting outside in the sun. With a glass of good cheap wine. After that we have to do the spanish lessons. We have 3 different courses on CD, DVD and accompanying books.

Then the weather is so fine that it would be a shame to go sit inside to write some software, so we sit outside in the sun and I do some reading in my favourite books (Programming PERL and PERL Cookbook). After that it is time for a drink and some nice food, and we go to the beach again. When we come back it is time to download the second email batch and start preparing dinner.

Somehow I have the feeling something is missing. The 4th dimension strikes back. Time has leaked away without any positive effect on mankind. Or has it?

I noticed this time leak thing has a positive effect on creativity. It tends to make your todo lists longer, thereby creating the need for more time. Which is not a circular reference; I am afraid it is a recursive function without a return condition...

One positive outcome has been a so-called crapmail filter for pskmail, which filters out all references to MIME stuff and advertizing and please unsubscribe this and that and our ADSL service is faster than yours...

This has already saved lots of time downloading the mail...

On special request I present a screen shot of our faithful visitor on 10.148 MHz, we call it the pregnant sea cow because of the characteristic sound. This screen shot was taken this morning while getting the mail from SM0RWO. The whitest bits are S7, and this time pskmail won the battle...
The signal is a distortion product from an active packet forwarding station about 1200 Hz up. The FT897 RX has AGC off, and DSP on the most narrow position (1000 Hz for both Low pass and high pass).
This sick signal has been here for months now, and I think the operator (?) of this station is deaf, dumb and blind.

I will donate a free beer at the next hamradio exhitbition in Friedrichshafen for the person who is the first to tell me what station I am talking about!! Maybe we can persuade him to stop this pollution (if he knows what that is).

The packet center frequency is around 10.149 MHz, and you cannot miss him.... he has been 3 kHz wide since I started monitoring this frequency!!

I came across a splendid idea the other day. One contest group has now installed a receiving antenna in a remote location. The connection to the station (K2 of course) is not via a coax cable, but via a broadband internet connection. Antenna direction switching and RX frequency setting can be done via the internet link (Tlf has been doing it for years), and a web cam makes sure you know immediately if the cows damage the antenna. The argumentation was: "we have too much noise at our contest location".

This set my mind off, and when that is the case there is no stopping...

I have seen a lot of nice, noise free locations on our various trips, one of my favourites being in the middle of the "Waddensea". You can hear the grass growing on Mars in that location (electro-magnetically spoken).

What if I hired one of those fancy satellite internet installations during a major contest, and auctioned the spot on EBAY!! Think about it. You are somewhere in California and you have tried to win the CQWW-SSB for the last 10 years but these darned guys in Aruba, HC8 or CT3 always win the pot....

This is your chance!!! You rent my antenna installation for the duration of the contest and you are the only one who can hear those thousands of low power and qrpp basterds in Europe who do not even bother to put up a decent antenna for the contest!! You can not imagine the pile up...

Now of course there is this rule that your antenna must be no further away from your main location than 500 meters, unless you own the property?

The solution is very simple. On the 1st of April I will offer you the opportunity to become co-owner of a small piece of land in the middle of Europe. I will auction ownership certificates on Ebay, and the bidding will start at $1000 per station per contest.

I will undertake to put an antenna on the piece of land, and facilitate a 1 MB/sec TCP socket to connect your station to. Stations in California will get 10% rebate as they are in a disadvantage anyway.

Of course we could strike a deal beforehand... If you don't want your competitor to grab this fantastic offer you can email me via pskmail...

Now how could I make this work for a M/M station? Could I organize an antenna for the Europeans which is located in Japan? Let's see. I would need to build 6 K2's, the satellite connection would cost Euro 90 for a month, .... And what about auctioning the roof of the camper including the fishing rod and the wire, that would make... There is a lot of mileage in this idea.

The financial aspects of my next vacation are settled!!!

This morning I had only one email waiting on pskmail, a 7k masterpiece from the crew of PI4TUE who were preparing for the PACC contest this weekend. The server at SM0RWO was a stable S7, as always in the late morning hours (we don't get out of bed very early here). So this was to be a piece of cake again.

And indeed, the first bit came in without problems and I enjoyed watching the block size of pskmail going up to 64 characters per block. If you are used to PSK31 or RTTY, that is quite fast, and the protocol overhead is only 6% in this case. But this was sunday morning, and it could not be true. There was an RTTY contest going on HF, and all non-contesters would be on 30 meters?

You bet.... The first intermezzo was a PSK63 signal, S9+20, that came smack on frequency and started to send

"rrrrrrrrrrrrrrrrrrrrrrrrrrrr" on top of the server. Pskmail got a hicup, but went on as if the rx had been dead during the intervention. 60 seconds later, probably the same station (did not send a call, so must be an unlis...) came back, this time with a lot more creativity: äskdjhnjklssjhhssssrrrrrrrrrrrrsjk,,fffmmklajdshjiwioinbnamjdbnj".

Interesting. The burper was actually communicating!!!

Pskmail went on, now with a block size of 16 chars/block, which makes the text slightly worse to read for an outsider.

Again a few minutes later: '"QRZ QRZ QRZ? What means 2615?""

As the email got really stuck now, and was not ready, I could not answer this interesting question. Meanwhile the number of repeats had triggered PSKmail to reduce the block size further to 8 characters/block, but it was still pushing the text through. The jammer gave up.

5 minutes later, a PSK31 signal came on our channel, exactly zero beat with our frequency, and started calling CQ I guess,at least I cannot imagine that he was in qso, as the SM0RWO server was still pushing text with an S7 signal.

PSkmail could get 1 block through out of 8 during the times the caller was silent.He gave up after another 5 minutes.

After this we only got disturbed by the "pregnant sea cow" living 1.5 kHz higher, supposedly passing packet radio trraffic. This guy (or girl for that matter) is so overmodulated that his signal is 3 kHz wide, and knocks our PSK63 signal out when he vomits on our channel. This normally knocks out only 1  block out of a sequence of 8, but the speed is going down dramatically because of the automatic block length adjustment.

I have made some pictures during this session (yes, this was one 40-minute session!)

This was not all. During the rest of the qso (1 email !) I was jammed by 2 SSB stations (this was 30 meters!!) who started a qso right on top of us, (PSKmail worked during the listening period of the loudest station), and 4 pactor stations, who just switched their burpers on without listening. Some of them started off-frequency, but completely blanketed the signal as soon as they switched to higher bandwidth. At one time I had an SSB qso with a pactor signal on top on our channel!!

But in 40 minutes time I managed to get the email through!!!

What I have learned during this interesting qso?

• Don't think any of the digital operators will listen on frequency before transmitting.
• Don't think an SSB station will give a damn if he ruins your digital qso
• Don't think any pactor 2/3 operator has a clue what he is doing
• Don't think he cares a damn about you losing your qso, he doesn't know who you are anyway
• When you use a different mode from the other guy you are an ALIEN, which must be shown he is not welcome here.
• Don't think ham spirit still exists in the digital sub bands

And this was 30 meters.... outside the WARC bands the RTTY contest was spreading anarchy.