Saturday, November 26, 2016

New Feature of the 2Tone RTTY Decoder

The 2Tone RTTY Decoder by G3YYD has been upgraded with a new feature.  This new feature is ON by default and in operation and causes 2Tone for look for strings of repeated characters that are at least 6 RTTY characters surrounded by space characters.  2Tone will then enclose those characters in brackets { } so that it will stand out better when you are looking at the received copy.

Version 3.50.294 of Logger32 contains this improvement:
The latest 2Tone RTTY engine has an auto-correlation feature. Support of this feature is added to the Logger32 2Tone windows.

Here is the description from the latest version of 2Tone about this feature:
This version of 2Tone 16.11a introduces a new function. It is an optional function that is enabled by default. It looks for repeated strings of characters surrounded by space characters and are are at least 6 RTTY characters. 2Tone combines the analogue data of the two strings and displays something like this { G3YYD }. The brackets indicating it is a combined version of the 2 strings with a lower probability of error than the single strings on their own. It is all based on statistics so sometimes there will be false matches. Sometimes the {} will not be correct while one of the strings is.

Extract 2Tone.exe to overwrite your current 2Tone.exe.

In setup menu, there are two new items: Repeat Match and Same Reject on.

Repeat match checked (default) will enable the repeated string matching function.

Same Reject on (default unchecked) when checked will surpress the { } output when both input strings are identical. This saves display clutter.

       [NOTE from W8TN: I found the "Same Reject on" feature was CHECKED by default and I had to change it to get the feature to work.]

Internally 2Tone uses auto-correlation of the analogue data to find probable repeats of information. To eliminate potential false positives, the repeated character strings are identical and surrounded with space chacaters plus being at least 6 RTTY characters.

Sent message like " DAVID DAVID " will work but " ED ED " will not - not enough characters . Nor will " DAVID DAVID, " work due to comma at end. " IO92NQ IO92NQ " will work as will " M7T M7T "

This is the way G3YYD describes the new feature in his announcement to the RTTY Contesting Group:
This new version fixes a few minor items but the big one is it will now look for character strings that are repeated and combine the analogue data together to provide an output that has a lower probability of error. To distinguish this synthetic output from what was actually decoded its output is surrounded by curly {} brackets, e.g. { G3YYD }. Occasionally, it will get the matching wrong and give a false output. It is possible to turn this off see the documentation that comes with the upgrade.
In the recent WAE RTTY contest two stations in the UK found that in 4% of their QSOs that this new system saved asking for a repeat. The normal repeat request rate is 8% of QSOs. A 50% reduction is very worthwhile.
It does however require that the sent information is correctly formatted, which it is in most cases. The format required is for the repeated characters to be at least 6 RTTY characters long and surrounded by space characters. Examples of this are, the quotes are for clarity: " G3YYD G3YYD "  or " DAVID DAVID " or " IO92NQ IO92NQ ". However  " ED ED " will not work too short or " DAVID DAVID, " will not work comma after 2nd DAVID. " M7T M7T " will work as the figure shift, letter shift and a space character make it 6 RTTY characters.
It is not just for contest, it also works for everyday QSOs. Just make sure when sending you name, QTH etc to apply the rules as above when setting up the macros.
73 David G3YYD aka M7T in contests

For Logger32 users:
Bob/K4CY has incorporated this feature in Logger32 with an added twist. Logger32 users can opt to convert the   { G3YYD } to G3YYD  . Right click on the 2Tone decode window and check “Underscore corrections/recommendations.”

Below are a couple of screenshots of how this looks.  It was difficult to find any RTTY signals this morning with the CQWWDX CW Contest running so I had to use a pre-recorded sample RTTY file and a YouTube video to get some RTTY signals.

This first one shows the output of 2Tone recognizing a repeated character string (7L4IOU 7L4IOU) and the auto-correlated output is surrounded by curly { 7L4IOU } brackets.  I can see where this might help you notice the callsign better when there is a lot of text displayed on the screen.  Note that in the line above it auto-correlated (176 176) and printed it as { 176 } to show that it had auto-correlated that text string.  [Click on any image to see it larger.]



 But, in trying to get more samples, I found that 2Tone was making many mistakes in identifying a repeated string.  Many times it would print two calls but then put inside the brackets (or underlined in Logger32) a different callsign.  To me, this could lead to more confusion.




In the above example 2Tone prints (GA7RY VA7RQ) as the two strings but auto-correlates that to (VA7RY) which happens to be the correct callsign.  Then it correctly copies (7L4IOU 7L4IOU) and auto-correlates that to (7L4IOU) correctly but also to (UL4IOU) incorrectly.

I guess I will just have to use this feature in the real world for a bit to see how useful it actually is.  If I find it to not be useful, a simple mouse-click can turn it off.

You can download the latest 2Tone program as a ZIP file here:

For those with Logger32, you need to download the latest version of 2Tone (16.11a) as a ZIP file, extract the contents, and copy the “2Tone.exe” and “2Tone.pdf” files into your Logger32 directory.

Thursday, April 28, 2016

2015 Intrepid Spirit Award Recepient - JH1AJT

Zorro - JH1AJT
I just saw a post on N6PSE's Blog titled "The 2015 Intrepid Spirit Award goes to Zorro-JH1AJT." It was posted on April 17, 2016.  You can see the photo of Zorro with his award on the right.  The Blog post states:
"This year’s award goes to a notable Dxer and Dxpeditioner that we have come to respect and admire greatly, Mr. Yasuo “Zorro” Miyazawa-JH1AJT.

This award is to recognize Zorro’s outstanding efforts to activate Eritrea, Myanmar and Bangladesh. Zorro is largely responsible for fulfilling the need for Eritrea, Myanmar and Bangladesh contacts. We recognize Zorro’s unselfish acts to activate these challenging and much needed entities.

We acknowledge Zorro’s pursuit of operating excellence and his quest to activate the rare and often difficult entities. It is for these reasons that we honored him with our Intrepid Spirit Award, presented at the International DX Convention, Visalia, California on April 16th, 2016."

That name rang a big bell in my head.  I remembered having a most intriguing conversation on 10-M SSB while I was driving North on Interstate 77 in Jackson County, WV, with a Japanese ham who had that same name.  I pulled out my Mobile Log and quickly found that QSO.  His QSL was right on top in my Mobile QSL file!  I was correct, I did have a QSO with this same individual way back in 1980!

Below you can see my Mobile Log and the QSL.  The QSO is the last one on this page of my log.  Click on either image below to see a larger image.

I have told dozens and dozens of folks over the years about how much I enjoyed that particular QSO.  According to my log it lasted just 13 minutes but it left a lasting impression on me.  Signals were fantastic and I had absolutely no problem copying or understanding anything Zorro said.

This QSO took place from 4:32 p.m. to 4:45 p.m. local time here in WV.  That would have meant it was between 5:32 a.m. and 5:45 a.m. in Japan.  For the middle of September, that was just about 7 minutes past his sunrise.

If only 10-M would come back to the conditions that were in effect at the time I made this QSO!  Still, I will always have this wonderful memory of a really fantastic QSO made nearly 36 years ago.  Thanks, Zorro!

Wednesday, March 2, 2016

Snap On Split Bead Ferrite Chokes for Noise Reduction

This morning I spent over an hour trying to work a station on 17-M with no luck.  Toward the end of that effort his signal dropped down into the noise and I decided to give up the chase.  As I was shutting down everything I noticed an issue.

I have a small program that runs on my shack computer which communicates with the SPE Expert 2K-FA amplifier over a USB cable.  I can turn the amp ON/OFF, put it into standby, and monitor its front panel display right from the computer.  Today I shut off the amplifier using that program and then when I closed the program itself, I noticed a change in the noise level in my receiver.  It was a small change but, nevertheless, it was there.  I turned the program back on and the noise came back.

Below you can see a screenshot from the Audacity program which is showing the noise from my receiver when switching the program on and off.  The line of numbers at the top beginning with "0.0", "1.0", "2.0" etc. is seconds.  Beginning just after 1.0 seconds until 4.5 seconds and again at 7.0 until 9.5 seconds, you can see the increased noise level when this computer program was running.  The lower noise displays are when the program is not running.



It is not a huge amount of noise, but, it is still there.  Adding just that much noise can at least make it more difficult to copy a weak station even if it does not cover up the station.  Add this little bit of noise to the noise generated by other pieces of equipment in the shack and it all increases the likelihood that you will have difficulty in hearing the weak ones or it could be enough that you don't hear them at all.

It is apparent that when this program is running, it is sending data back and forth to the amplifier along a USB cable that runs behind my radio.  That data stream is being picked up by the receiver as noise.  The noise is still there with the amplifier off.  It is only when the program is closed that the noise goes away.

Recently I purchased some Snap On Split Bead Ferrites from Palomar Engineers (http://palomar-engineers.com/) just for this purpose (image at left.)  I purchased a 25-pack of Mix 31 (1-250 MHz) 1/4-inch diameter snap on split beads for $50 and a 10-pack of Mix 31 (1-250 MHz) 1/2-inch diameter snap on split beads for another $50.  Shipping was $10.
I took one of the 1/4-inch Split Beads and snapped it on the USB cable at the computer end.  (The 1/4-inch ones fit well on Ethernet cables, USB cables, etc. for a 1-turn choke.  The 1/2-inch size will fit RG-8 cables or you can put 3 turns of Ethernet cable through the 1/2-inch ones for more choking if needed.)

Then, using the same settings on the receiver (same bandwidth, same band, same mode, same antenna, etc.) I listened for the noise when turning that program on and off.  The noise could no longer be heard.  Just to make sure I had actually found the problem, I removed the Split Bead Ferrite Choke from the USB cable and - the noise was back!

This problem turned out to have an easy fix which cost me $2.20 and about 1-minute of my time.  I plan to continue adding Ferrite Chokes to the computer cables in the shack, the Cable Modem, and to the feedlines to reduce and/or eliminate any common-mode issues I might have.  All these things add up to keep the noise away from the receiver so it can do its job and pick out that weak DX.  Every little bit helps!

Friday, January 22, 2016

Common-Mode Choke

Today was a MAJOR snow storm.  12" of snow in 10 hours and it is still coming down!  So, with nothing better to do, I decided to get caught up on some old projects that have been hanging around. You can click on any photo to see a larger image.

Looking Out my Front Door

The first project I decided to tackle was to build a couple of Common-mode Chokes for Jimmy, W8JA.  The one I built was 3-1/2 turns through two stacks of four Mix-43 toroids.  These are available from Fair-Rite as Part No. 5943003801.  This choke's impedance should exceed 1-K Ohms from 1.8 to 18 MHz. and dropping to 550 ohms at 30 MHz.  The full description can be found in an April 2006 document called "Common-Mode Chokes" by Chuck Counselman, W1HIS.  You can find it on the Internet.  

It's a pretty simple job to build this choke.  It is just a 36-inch piece of RG8/U type coax passing 4 times through the upper group of four toroids and three times through the bottom four.  My first job was to build a 36-inch piece of coax with PL-259's on each end.  I used Belden 8267 cable.  Below is a photo of one of the connectors after it was soldered to the cable. 


PL-259 Soldered to Cable

Below is a photo of the completed choke.  You can wind the choke through the toroids with the PL-259's already connected.  So, instead of building a 36-inch piece of cable from scratch, you could just purchase one and wind it through the toroids.  I used a couple of Ty-Raps to secure the windings so they did not "un-wind."  An Amphenol PL-258 double-female connector with Teflon insulation is connected to one end to simplify the installation of this choke either at the antenna or at the rig.

Completed Common-Mode Choke
Building the cable from scratch took some time.  I need to improve my method of doing this if I plan to build many more!

Still, I got one project off my "To Do" list today while "snowed-in"!  On to the next!