To CQ or not to CQ?

I have been on 20 + 30m JT9 mode now for few weeks. The band seems to be completely dead, but every now and then I get a QSO.

A dead band is dead if no one is calling CQ or if there is no propagation. And of course if there is no one to communicate with it is tough to make a QSO.

Please activate the bands and call CQ!

Cheers,

Toni oh3t

Digital mode boom in OH land

Over the past few weeks I have been actively promoting JT modes in local HAM radio forums.

I have written emails and local wiki guides with links to various pieces of software.

JT modes seem to facinate many operators. So.. if you see sudden burst of activity from OH land please give these stations nice QSOs!

Cheers,

Toni oh3t

Keeping the JT9 bands warm

I think it is the chicken and egg problem.

HAMs continue working JT65 still even it seems to be history. JT9 has significantly less bandwidth (only 16Hz!!) and even better decoding capacity in bad conditions.

I am committed keeping the JT9 signal on air! When I am at (or remoting) my  computer I will call CQ. After a long configuration work I got my Yaesu G-1000DXC rotor also working with my computer and HRD Rotator software. So the rotor is also working with remote commands.

Main bands 15, 20 and 30m. Usually I am calling JT9 CQ around 800Hz (+2 kHz selected) with WSJT-X software.

During the past two weeks I have worked more than 150 stations with JT9 mode, some with more than one band. If you feel like it you can work me several times even on the same band.

Most important thing, let us keep the JT9 bands warm!

Cheers,

Toni OH3T

Why do I keep getting bad JT9 signal reports?

 

I have been active on JT9 mode recently. I think this mode has great potential for becoming one of the leading HF digital modes, even for DX-pedition purposes (some tweaks needed though).

I am running digital modes exclusively with my great little Flexradio Flex 1500 and I have a small QRP linear amplifier boosting the signal to 20-30 watts.

Based on reports on-the-air the typical TX power in JT9 mode seems to be between 5 and 30 watts. So I am perhaps running it in the upper end of the scale. Having said that, my normal report is 10-15dB lower than what I send back. This seems to be quite consistent on various bands. So what the heck is happening here?

JT9 has dB in S/N

JT9 is great in tough band conditions and when the conditions are good you can run qrpp and still get great results. The dB in WSJT-X user interface is Signal to Noise ratio (S/N), not the signal strength of the signal you are receiving. Of course, a strong signal usually also means better readability, thus larger S/N dB figure in the user interface.

Instead of me trying to explain the S/N please refer to Wikipedia:

S/N ratio explained

Quad has less noise than Yagi!

I wrote last year in this blog about my Quad project. I have now more experience from this antenna alongside with my yagi. The Quad antenna system has definite edge over the yagi in signal readability! Less static coming from antenna equals better S/N.

I still have the 450 ohm ladder line routed from my ham shack to the tower. The project to move the tuner to the tower is still work in progress and my target is this spring.

Tuner as pre-selector

Due to antenna construction the radiator has to be tuned. My DIY tuner is based on great hiQ S-match design by PA0FRI. This tuner has quite narrow band-pass filter functionality built in.

S-match information

My S-match prototype in the picture (silver coil roller inductor, vacuum capacitor, Amidon toroids, red wire is silicone insulated).

The tuner acts as a narrow pre-selector in similar fashion than how magnetic loop antennas work.

This type of antenna matching effectively eliminates noise going to the rig.

Fully digital signal processing chain

Have you ever heard complaints about audio ground loops or RF in audio when you are transmitting? I have suffered perhaps from every issue possible regarding RF and audio problems. Not any more! When I switched to Flex 1500 all those nasty RF and receive noise issues were simply gone. Once the Flexradio has transformed the received signal to I and Q and digitized those the received audio never leaves the computer. The processing from Flex to WSJT-X is done fully digital eliminating all those nasty RF issues. I highly recommend this type of fully digital setup for anyone seriously involved with digital modes.

Location, location, location!

Last but not the least. Perhaps the most overlooked issue is the location of the QTH. As I have written in my QRZ.com profile. “My QTH is one of the highest points in near vicinity and my antennas are 120m above sea level. Nice clear takeoff angle to all the directions with reasonable noise level.”

One of the exceptions regarding the reports was G7APP. I sent –01 and received +01. I checked the location of G7APP from QRZ.com and google maps. No wonder I got such a great report! Great countryside location!

Final thoughts

I have stopped worrying about the JT9 reports. The report is the indication of one’s working conditions, not necessarily an indication how strong the transmitted signal has been. The software on both ends is the same, the S/N dB calculation is done with exactly same algorithm.

If you constantly receive better reports than what you send, please consider what I wrote above.

Hope to work you with JT9!

Cheers, Toni oh3t

Fun With Flex 1500 and JT-65

CQ CQ

In the passband you can see JT65-HF traffic and a little bit below is very active PSK traffic.

If you have never tried JT65-HF I definitely recommend trying. It is fun mode to work and very effective during tought band conditions. And even better, you never know who answers when you call CQ. With just 5 watts you can work the whole world!

And finally from the pskreporter we can check the propagation. And here we can see that my JT65 transmission is heard in VK and YB land as well.

My quad stack was beaming to NA.

Break Is Over

Finally some activity also in this blog.

Antennas are still the same

No improvements to antenna setup during summer :(

I tore a ligament in my right hand during antenna construction just before summer while building new radiator elements for 12 and 10 meter bands. I guess it is needless to say that my summer antenna construction season was basically over before it even started.

Maybe next year with better luck.

Natural High

Natural High for Antennas

What is the best way to launch antennas to trees?

I have been using a fishing rod and a golf ball for quite some time to sling the antenna wires over trees. That setup has been working reasonably well, but it has been lacking accuracy and a bit more height is always preferred.

Here is the my antenna launcher. I found reasonably cheap used long bow. The bow is 44 pounds strong. I drilled a hole to a golf ball and glued the arrow with strong epoxy. Then I shortened an old baitcasting rod and used hose clamps to connect it to the bow.