SolderSmoke #87

July 6, 2008     

http://www.soldersmoke.com
               
On the beach at Fregene
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QRSS Mania:
Calibration problems solved
First reports received
The Fun of Grabbers
Checking your signal via Blackberry
The Joy of Milliwatting
Chirp, Click, Drift in QRSS
Temperature sensitivity
Bury that Beacon?
Why so little US QRSS?
More US Grabbers needed
AA1TJ/QRSS?
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Elser in "History of QRP in US"
New Slides, WAC on ClustrMap!
MAILBAG: G0FUW reports EI9GQ victin of Knack
KC0PET on understanding our circuits
ON4FW sends FB pictures
KG6TCJ on QRSS calibration
W7ZOI on FD and calibration
W4NI on measuring harmonics
PE1OIT on GPS calibration technique  

The QRSS View from ON5EX -- July 5, 2008

I wanted to give you guys a sense of what you can see on the QRSS Grabbers. The grabbers are just the output screens from the Argo or Spectran (or other) software that have been placed on-line, updating every few minutes. In the screen shot above, you can see the sophisticated signal of Eddie, G3JZO, pounding into Belgium (this is the Grabber of Johan, ON5EX). My much more basic effort is visible as a line of Morse Code just below Eddie's sig. Above Eddie you can see the "snake CW" of IQ4FJ. Along the bottom right of the screen, you will see the square wave signal from the 5 mw solar powered beacon of Paolo, IZ1KXQ (scroll down a bit to see his rig, and his schematic). I think the vertical stipes must be lightning.

Check out I2NDT's Grabber Compendium (but be aware that not all of them are on 24/7):
http://digilander.libero.it/i2ndt/grabber/grabber-compendium.htm

In this screen shot from I2NDT's Grabber, you can see the effect of me turning the air conditioning on in my shack. I have added a bit of insulation (an ARRL Handbook placed on top of the beacon box!) and things seems to have stabilized. With the entire "QRSS band" only 100 hertz wide, it doesn't take much to slide your signal all the way across the band!

Cleaning up my QRSS Signal

This week I worked to improve the quality of my 30 meter QRSS signal. At first I was pleased to just be in the band and visible on the grabbers. But soon I grew jealous of the very clear and clean dots and dashes of IK0IXI and others. My droopy dashes ("Italian tears") were getting embarrassing. Making matters even worse, when conditions were good, very noticeable key clicks became visible on the grabber screens. These became known among the Knights of QRSS as "shop hooks." I thought they made my signal look like some sort of Arabic lettering. Clearly something had to be done.

Yesterday I put a seven volt zener diode voltage regulator in the oscillator circuit. I also drastically reduced the size of the the capacitor that connects the oscillator to the first RF amplifier. This seems to have done the trick. The clicks are gone and the dashes no longer droop. Power out is now down from 200 milliwatts to 20 milliwatts. That's fine -- this puts me in the power range favored by the Knights.

The narrow-band nature of QRSS work makes imperfections very visible. A chirp or click that would be undetectable on ordinary CW becomes very apparent in QRSS. This morning when I adjusted the air flow from the shack air conditioner, I inadvertently sent the stream of cool air toward the beacon transmitter. With the On5EX beacon on my screen, I could almost immediately see the resulting frequency change!

The on-line grabbers are really fantastic. They give you and almost real-time ability to check band conditions. Almost all day I can see my 20 milliwatt signal arriving at ON5EX. Depending on time of day, you should be able to see my signals here: http://www.on5ex.be/grabber/grabber.html Look for me around 10140060 (+/- air conditioning).

Why isn't there more QRSS activity in the USA? Why are there so few American grabbers?

Over the Alps with 5 Milliwatts and Solar Power

Yesterday morning the lower portion of the 30 meter QRSS band was dominated by three Italian stations: Near the bottom of ON5EX's grabber screen was the very clear and FB CW of Fabio, IK0IXI. Fabio runs about 50 milliwatts to a Windom and operates from Civitavecchia, a beautiful coastal town about 20 miles from Rome. Here you can take a look at his rig, and his schematic: http://www.geocities.com/ik0ixib/bcn.html A bit further up were the droopy dashes of yours truly, 200 mw (QRO!) to my all-purpose end-fed wire. And a bit further up from me was the very interesting signal of Paolo, IZ1KXQ. Paolo runs 5 milliwatts from a super-simple solar powered rig (see above) that resides on the roof of his house. It puts out a distinctive square wave sig.

IKoIXI's crystal is in an oven and is temperature stabilized. He stays on the same freq all day. We've found that my signal seems to drift down in freq during the course of the day, as Rome heats up. It moves about 15 hz down from early morning to afternoon. IZ1KXQ's rig is more exposed to the heat, and seems to move quite a bit more, and his sig moves UP in freq. I think this drifting adds to the QRSS fun.
FB Paolo! FB Fabio!

Here is IZ1KXQ's schematic:

Crossing the Pond on 200 milliwatts QRSS

As you can probably tell, I was really pleased to get my little QRSS station in operation. But then came some icing on the cake: Vernon, VE1VDM, sent a screen shot (above) that showed the unmistakable traces of my somewhat chirpy signal. Look around 10140020 Hz . See those kind of droopy dashes? They're mine! (Johan, ON5EX, called them "Italian tears.") Hooray! Crossing the pond on 200 milliwatts!

Of course, this is no big deal in the QRSS world. 200 milliwatts is decidedly QRO for these fellows. I feel some pressure to reduce power. I also feel the urge to clean up the chirp, but then again, the Italian tears make spotting the signal easier.

For a great explanation of how QRSS allows you to pull signals out of the noise see ON7YD's excellent article: http://www.qsl.net/on7yd/136narro.htm

The online "grabbers" add a very interesting dimension to this. You can watch the band from stations around the world simultaneously. Take a look at I2NDT's grabber compendium:
http://digilander.libero.it/i2ndt/grabber/grabber-compendium.htm

Here's something else that I found really cool: I can watch the grabbers on my Blackberry! So, the other day, with my beacon on, as I made my way through central Rome on the 63 bus, I pulled out the Blackberry and opened ON5EX's grabber page. There I could see my droopy dashes at 10140020. Now I've got my eye on the grabber of Laurence, 9V1LF, in Singapore; I hope to put some Italian tears on his screen soon.

Guys, this real "essence of QRP" stuff. I'm reading Ade Weiss's book on the history of QRP, and I often find myself thinking that The Old Man and the QRPers of yesteryear would very much approve of QRSS.

It may seem complicated, but it is not. The transmit systems are just milliwatt crystal-controlled transmitters and some sort of keyer (mine is from K1EL). For receive, all you need is a cable from your receiver to your soundcard, and some free software.

We need more QRSS activity from the States. When will AA1TJ put one of those Zener Diode rigs on 10140030?

QRSS Success -- Signals Visible in Online Grabbers

Shortly after recording SolderSmoke 86 (in which I shared my tale of QRSS woe), I solved my calibration problem. IK3NWX has a CW beacon on 10141800 Hz. I fired up the Spectran soundcard program, and put the output of my Drake 2-B into the line in connector. With the 2B's bandpass wide, I tuned NWX's beacon to the top of the display. I then adjusted the trimmer cap on my oscillator to put me 1750 Hz below NWX. Eccolo! That put me in the 100Hz wide QRSS band. Almost immediately I could "see myself" on some of the on-line "grabbers." Vic, G3GKI, sent a screen shot (above) You can see some chirp on my signal. I might fix that, but I might leave it as is to make the signal more easily recognizable.

Eddie, G3ZJO, also sent a screen shot. I think this one is from an online grabber located in Northern Italy. You can see Eddie's far more sophisticated signal higher up in the display. My more rudimentary effort appears below. You can make out my call.

The online grabbers are a real hoot. My favorite is that of Johan, ON5EX. Check it out and see if you can see my 200 milliwatts reaching out across Europe. look for me around 10140020. Johan's page updates every minute or so:

http://www.on5ex.be/grabber/grabber.html

SOLDERSMOKE 86

June 22, 2008

http://www.soldersmoke.com

Maritime Mobile on Lake Bracciano.
Jean Shepherd loses girlfriend due to THE KNACK.
30 Meter transmitter self-constructs (almost).
QRSS Woes.
Do CW signals have sidebands?
Freq Counter down for the count.
Dial Parallax: Drake 2B jumps 3 kc from eyeball to eyeball.
Radio Shack: Count your blessings!
Nice wire from old computers.
Good luck on Field Day.
MAILBAG: VU3RDD NEW HARMONIC!
Frank on analog scopes,
PE1OIT on si570 chips,
KG4ENB on 179 kc LOWFERS,
M0NJP on how XYL's can deal with THE KNACK,
K7JM on SolderSnow,
W8OAJ SolderSmoke as Knack Therapy,
Jonathan 7J1AWL "from commuter train in Tokyo"