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Archive for the ‘Digital Modes’ Category

WINLINK2000 Packet info

2011/05/07 1 comment

Winlink free links:
http://www.winlink.org/

Download free user software: RMSExpress or Paclink
ftp://autoupdate.winlink.org/User%20Programs/

Mendo folks can contact me for help and tips setting up APRS or Winlink. Alan n6vud Ukiah alan@spamcop.net

Other great sites and software:

The best internet APRS site
http://aprs.fi/

OpenAPRS hosted by a ham in Napa. You can send APRS messages to other hams from this site.
http://www.openaprs.net/

The best APRS home software APRSIS32
http://aprsisce.wikidot.com/

Checkout my APRS links from last years APRS presentation:

https://mendoradio.wordpress.com/2010/08/24/aprs-web-links/

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ZZ Wave Net, an Interesting Antenna

Yesterday, I finally got on 40M PSK31. That happened because on Saturday I finally tuned my 40/80M dipole down to the lower end of those bands (removed the tuner, yeah)… and also because Len, WA6KLK, was so kind to offer me a Rigblaster (for a decent price.) So, I no longer had to fiddle around with 600 ohm transformers and resisters to balance out the AC hum creeping into my various digi modes. Optical isolation is so much cleaner.

Anyway, one of my first contacts was Mike, VE6VIS, in Glenevis, Alberta Canada.  We got to talking about antennas, and he told me about his ZZ Wave Net, quite an interesting antenna design.  It’s a loop antenna with a cool geometry. It looks like something that might take off and fly. Mike says it puts out a good signal (which I can confirm that from the solid PSK QSO that lasted much longer than I thought in fluttery/fading band conditions.)

As you know (or may not) some of us have been discussing what kind of antenna to build next. I mentioned the TTFD and K9AY in my earlier blogs, and I’ve also been looking closely at the double extended zepp recently proposed by Steve, Ki6EIF. (And if it hadn’t been for the sudden appearance of the rigblaster yesterday and difficulty in measuring the capacitance of a 2 inch piece of coax, I would now have one on the air for 10M.)

But, Mike’s ZZ Wave Net loop definitely looks like a fun antenna to try out. He told me he was originally inspired by those bow-tie UHF TV antennas which are very boad-banded (see further down his page for the ZZ BowTie which is 1:1 across the 20M band.) And, it just so happens I’ve been thinking about building one of those for some of the higher ham bands… mainly due to the ease of construction, low cost, and wide bandpass.

So many antennas… so little time.

Categories: Antennas, Digital Modes Tags: , ,

Addicted to PSK31?

Some folks told me PSK31 can get addictive… and now I’m beginning to believe that.

It’s kind of like CW, without the code, times 10. Why? Because often, on 20M (14070), you’ll hear 10 or more stations all within the 2.8KHz passband of your receiver.

Most of the QSO’s are short and to the point, just like CW. RST, QTH, name, and maybe a bit about the rig, power, and antenna. Of course, you can rag chew if you want.

Plus, many of the stations are great DX at low power. Using 30 watts, I’ve worked QSOs across the USA, but also in Russia, Italy, various pacific islands… and I’m still really new to it.

If you’re interested in this mode, I encourage you to give it a try.  My main advice is to remind you to keep the power down… because strong stations kick in everyone’s AGC, making it difficult to copy weak stations in the same passband of the receiver.

I hope to see you on PSK31. 73 -Carl KB6ZST

Categories: Digital Modes, Operation Tags:

Diving into PSK31

2010/08/26 2 comments

Last night I heard a CQ at 14,073 using the Olivia 8/250 digital mode. It’s not that common… sort of sounds like a cat doing somersaults on an electric piano. After quite a while the station finally gave up… having made no contacts.

I wanted to make that QSO so badly… just because he was a solid 599, but I didn’t have the transmitter hooked up!

The event motivated me to figure something out. Although not the cleanest connection, I wired the audio output of the computer directly to the HF radio’s patch input. Then, because my computer has no serial port, I used the VOX rather than the PTT input to trigger the transmitter. Of course the audio was a tad hot, but by dropping the mic gain low and adjusting the computer’s audio output level, managed to get a clean signal with no obvious distortion.

At this point, with the CQer long gone, how could I figure out if the rig was getting out? Decided to dive into the pool with PSK31 on 14.070. My first contact was N8MJK, Erik, in Cabrillio, CA. He gave me a good report, as well as quite a few useful hints on how to work PSK31. (He’s also an old Amiga Computer user, so that was cool.) Managed to make a few more contacts, and each presented interesting challenges.

Well… I learned a lot, and I can tell you that PSK31 is a blast. It’s sort of like CW in a way, because you’re juggling copy with trying to figure out the content of your next transmission at the same time… all at about 31 baud.

Anyway, it’s easy to get started. Give it a try. Dive in.

And yes, I’ll wire up a better computer-to-transmitter connection… maybe via a pot or transformer.

Weak Signal Modes on HF?

Have you ever tuned around 20M when the band is totally dead and not a station can be heard… but you hear this odd sound, like a kid playing songs on a cheap synthesizer? You might think, “Hey, what’s that kid doing on the ham bands!?!”

Well, it’s no kid and no kidding around. It’s actually a digital mode for extremely weak signals, and it’s quite interesting because you can use it to communicate even with signals that are 10db below your human audio perception level!

Introducing WSJT

The program that does this is called WSJT, and it was created by Nobel Prize winning Princeton professor, Joe Taylor, K1JT. Its purpose is to send and receive various weak signal modes for meteor and ionospheric scatter as well as EME (moonbounce) on VHF and UHF bands. And, it’s both free and well supported. (WSJT Summary Page)

But, did you know WSJT is great for HF skywave propagation too? You can sometimes hear it on 20M around 14.090 +/- 10 Khz, and it sounds like a poorly written song.

Songs on HF?

Why a song? Well, here’s my 2 cent theory on it: When you hear a song, you may not now precisely the next note, but you sure do know what notes you’re not going to hear. In other words, you correlate what’s going to be heard next. You don’t know the exact note, but you statistically know what the “scale is” so you’ve actually gained some information. In fact, you’ve added true gain to your actual signal detection, just like you would with a better antenna. Cool, eh?

I first heard of this method called auto-correlation back in the early 1980’s when building an ionosonde receiver for NSF. Back then this mode was used for microwave-band tropospheric backscatter detection (using a 3 megawatt ERP beam). But now, any ham can use similar techniques just by connecting the audio channels of your computer to your HF, VHF, or UHF radios, and you can do it using just QRP, not megawatts.

Using WSJT

I discovered how to use WSJT by accident. A couple weeks ago I was tuning around the 20M band during a solar flare and meteor shower trying to decode whatever digital mode I could find. I came across a signal that sounded almost identical to MFSK (multiple frequency shift keying, the name for using a fixed set of tones at different frequencies, and when sent via SSB, it’s actually a very crude low bandwidth digital form of audio-based FM.)

Anyway, I spent two hours trying to decode the MFSK signals but could not. That’s when I remembered Len, WA6KLK, telling me about WSJT and weak signal EME modes. On a whim, I tried the program, and it worked! (You know you’ve got an interesting program when part of its window is showing you the azimuth and elevation of the moon updating in real-time.)

The first station I decoded was a UA0LOQ in Vladivostok, Russia, running 60W. But, here’s the cool part, the band was otherwise dead… and his signal here in Ukiah was 19 db below the noise floor!

It’s not a difficult program to download and run. You can get it operational for reception in just a few minutes, assuming that your computer’s input audio is connected to your rig. Just spot a signal on HF in SSB mode (around 14.090 +- 10Khz) select from the mode menu JT65A (F8 key), hit the Monitor button, and wait a few minutes for messages to appear. Each message is very short, just a few characters, so hams tend to use a lot of abbreviations, similar to CW.

If you can’t hear a signal, go to the WSPRnet Map to check propagation. WSPR stands for weak signal propagation report. It’s a ham network of QRP stations probing the skies for current conditions. The WSPR Database page will show you activity spots.

Of course, the WSJT program has many other features and modes, most of which are still a mystery to me, but the success of using it on HF motivates me to learn more.

So, I encourage you to check it out. It costs nothing to try, and it offers some amazing “gain” for weak signals… and I’m hoping that some of us in Mendocino county might get together and do a moonbounce project of some kind. Fun stuff.

APRS Web Links (Updated 05/07/2011)

2010/08/24 2 comments

Some good APRS sites

Best web site to look at objects: http://aprs.fi/

APRS info: http://aprs.org/fix14439.html

Best windows home or I-gate Free APRS software APRSIS32

http://aprsisce.wikidot.com/   To download your free copy, join the APRSISCE  Yahoo Group at http://groups.yahoo.com/group/APRSISCE/

To download your free copy, join the APRSISCE Yahoo Group at http://groups.yahoo.com/group/APRSISCE/

Windows Home station programs & I-gate: www.ui-view.org/

Linux Station program: www.xastir.org/

Lots of programs: http://www.agwtracker.com/

Free Sound card AGWPE Packet decode program: http://www.sv2agw.com/downloads/agwpe.zip

TinyTrack4 and others, and interface cables to your HT or Mobile: http://byonics.com/

APRS HOGS: http://www.norcalaprs.net/usagex.html

APRS Symbols: http://wa8lmf.net/aprs/APRS_symbols.htm

NORCAL APRS Group: http://groups.yahoo.com/group/ca_aprs/

NORCAL latest settings: http://info.aprs.net/index.php?title=NorCal_APRS_Regional_Info

OpenTracker2 (OT2M + Nuvi-350) Also interface cables for your HT, or Mobile: https://www.argentdata.com/products/tracker2.html

Setup audio TX: http://www.febo.com/packet/layer-one/transmit.html

Setup audio RX: http://www.febo.com/packet/layer-one/receive.html

UiView Help Page: http://www.mcminnarc.com/aprs/aprs.html

Kenwood APRS Mobile: http://www.kenwoodusa.com/Communications/Amateur_Radio/Mobiles/TM-D710A

AVMAP-G5 Hooked to Kenwood Video: http://www.youtube.com/watch?v=IPH4mwn4uko Yaesu FTM-350R

Hand helds: VX-8r Closeout, VX-8DR, and cheaper VX-8GR: http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=111&ProdID=1577&DivisionID=65&isArchived=0

Local hams do you need help? Contact Alan n6vud in Ukiah for help alan@spamcop.net