More T/Rouble

I get the RTS signal when using a Windows PC, but when I try to switch over to a Linux computer, I don't get the T/R signal from pin 7. Is there some code or setting in Linux that I need to change to make this happen?

Working on T/R circuit for HB WSPR rig --need help!

I'm finally working on the PTT T/R circuit for my homebrew DSB /Direct conversion 30 meter transceiver. I hope to use the simple one transistor circuit from W3PM's FB HB WSPR rig.

But I need info on the PTT signal that will come from the computer serial port. Which pins on the 9 pin serial port connector? What kind of signal comes out? Is it 5 volts on transmit? What settings should I use in WSPR? RTS? Any other setting changes needed?

I hope to be transmitting AND receiving soon.

WSPR Direct Conversion Receiver: On the Air and Online

In a testament to the sensitivity of the WSPR system (and I mean that in the technical, not the emotional sense) I got a couple of reports indicating that my very QRPp WSPR signal was, well, a bit obnoxious. I think part of this results from the fact that I'm one of the few people using a double sideband transmitter -- the lack of filters makes my signal look a bit different. But I do have an AC hum problem that shows up on receive screens. And because I haven't worked out the circuitry to allow the WSPR software to move my little transceiver from transmit to receive, I'd been leaving it in 100% transmit mode. I can understand why people didn't really like that.

So, on the theory that it is better to give (reports) than receive, and in keeping with the old idea that all ham radio stations should from time to time RELEASE the push to talk switch and LISTEN, I have magnanimously taken my homebrew DC/DSB WSPR system into receive mode. I'm in 0% transmit. I'm listening all the time, and automatically uploading reports on the stations I hear. Pictured above is the map from WSPR system page showing my spots from last night. Below you can see what my own WSPR system display shows. (I need to adjust my W3PM oscillator a bit. I may be a few hertz off and I am probably missing a bit of the 200 hertz wide WSPR band).

I was pleased to see W3PM's call on my map. An article by Gene provided the inspiration (and much of the circuitry) for my WSPR rig.

My receiver is very simple: The RF from the antenna goes through a low-pass filter directly to an SBL-1 mixer (thanks to Jim -- AL7RV). There it mixes with LO energy from the W3PM Colpitts oscillator. From there it goes to the KA7EXM discrete component AF amp.

You can watch -- almost live -- the stations I am receiving by going to
http://wsprnet.org/drupal/wsprnet/map
just type N2CQR in the box that asks for the call.

Down-Under Double Sideband WSPR

Peter Parker, VK3YE, is one of the real DSB Gurus. When I got started in the world of double-wide RF, I would frequently turn to his web site for ideas and inspiration. So you can imagine my delight in getting this e-mail from him (his DSB WSPR video is embedded above):

Hi Bill,
Discovered SolderSmoke a few weeks back and love the show.
You might be interested that another DSB WSPR station is on air.
A video demo appears at http://www.youtube.com/watch?v=2aUHNRgV7kw It's still very crude (eg manual T/R switching) and the receiver is getting false spots. However the transmitter is working very well, with some long distance spots.
73, Peter VK3YE

SolderSmoke Podcast #129

January 8, 2010
SolderSmoke Podcast #129

http://soldersmoke.com/soldersmoke129.mp3

Introducing Cappuccio (pictured above)
"On the Cover of the Hot Iron"
Old tech, new tech:
Hammarlund HQ-100
Lafayette HA-600 (A)
WSPR: VK6 on the grey line, also Wake Island, and Alaska
How I fixed a broken GPU chip using a light bulb!
EMRFD's cool mod of the SBL-1 Diode Ring device (from W6JFR)
MAILBAG

Please send me reports on the audio quality. I made some changes...

Propagation Improving

Yesterday spaceweather.com was reporting that a big sunspot was coming around the solar rim. I guess it arrived! Last night my WSPR sig was picked up by VK6XT during what must have been a gray-line situation, but this time with me going into sunset. Then, just about all night I was being picked up by VK2DDI. So, there may be hope for this solar cycle. 2011 seems to be off to a good start!

More WSPR DX

I was pleased to find this report (above) on my screen this weekend. Wake Island.

This morning I saw that yesterday I was picked up by one of the world's most globe-trotting hams: Laurence KL1X (by his remote-controlled station Kl7UK).

GO WSPR!

DXers: What is my path to VK6XT?

I've been looking with pride at the WSPR map (below) showing that my little beacon has been received by far-off VK6XT. He picked me up again this morning, again only once. That makes three days in a row, each day only one report. Each time VK6XT is the only station in the Oceania area receiving me. And each day the my signal makes the trip around 1025 UTC. Now, I'm not a skilled DX'er, but it seems obvious to me that we are dealing with grey-line propagation here, right?

The image above shows the view from the sun at 1025 UTC today. Obviously the day/night terminator is along the perimeter of the earth in this image. So, I guess my little sigs could have been travelling either short path over Northern Europe and down over South East Asia OR they could have taken the long trip down over South America, over Antarctica, and on to Perth. My guess is that the short path is more likely. In any case, as cool as it is, the map drawn by the WSPR system is not how the sigs actually travelled.

I hope you DX hounds out there will chime in and tell me if I'm on the wrong path here...

The Payoff from WSPR

Timestamp	Call	MHz	SNR		Grid	Pwr	Reporter	RGrid	km	az
2010-12-22 09:28	N2CQR	10.140215	-28		FM18jv	0.2	VK6XT	OF86td	18576	288
2010-12-21 10:28	N2CQR	10.140221	-28		FM18jv	0.2	VK6XT	OF86td	18576	288

I know some of you guys consider WSPR kind of weird, kind of narcissistic, more like broadcasting than real amateur radio. I hear you. As creator Joe Taylor himself has pointed out, these are not really QSOs. But I have to tell you, it is very satisfying to walk into the shack, and, with coffee cup in hand check the WSPRnet screen to see who has recently received your little QRPp signal. For the last two mornings, I've found VK6XT receiving mine. That's 18,576 kilometers covered by 200 milliwatts to a low dipole. In Western Australia my signal is 28 db below the noise (that means below the noise in a standard SSB passband). I see that I'm making the trip only once each day, at around the same time, and that VK6XT is the only Oz station picking me up. Very cool.

Here is Richard, VK6XT, the fellow at the other end of the path:

I was born in Christchurch, New Zealand in December 1954. Keen on shortwave as a boy, I went to Rangiora High School and met Gary Watson ZL3SV who sparked a lifelong interest in Ham radio. However Life intervened and it wasn't until 1976 in Wollongong, Australia that I first transmitted as VK2NNL.(after a brief fling on The illegal CB band). I upgraded and then returned to NZ to become ZL1OK from Rotorua. I became a DX hound and worked 256 countries for DXCC. The high point of my DX activities was in 1991 when I organised a DX-pedition to the Auckland islands. We operated as ZL9DX / ZL9YL and Kerry operated ZL9TPYon 6 metres. Always keen on home brewing and QRP gear I now work in Perth as a Design and Technology Technician. My ham radio activity is at present operating an Icom IC7400 to a variety of antennas 160m to 2m. . I am keen on the digital modes, especially PSK31, and spend my spare time on my hobby farm near Katanning(300 kM south of Perth).

Immediate Gratification: WSPR shows results very fast

So you build or modify a rig and you put up a new antenna and you then spend some time wondering if you're really "getting out," right? Well, wonder no more my friends! WSPR provides almost instant feedback on your work! Here is what the display looked like for my station a short time after I connected my modified transceiver to my new 30 meter dipole. Pond crossings were rare events before.

In my last post I asked if there were others running homebrew gear on WSPR. I am not alone! Paul, M0XPD, has put together a rig far more sophisticated than mine. Paul writes:

You ask if there are any others running h/b in WSPR...

My 50mW multi-mode beacon runs WSPR, DFCW and S/MT Hell on a 10-minute, frequency-hopping cycle.

It is entirely stand-alone - severing the umbilical cord to the PC gave me a really good feeling!

I'm currently working on a set of filters (BP and LP) to allow me to run on other bands (currently I'm on 30m).

Description on my blog: http://m0xpd.blogspot.com

A good radio morning at N2CQR

Today I had one of those really good ham radio mornings in the shack. My objective was to add one more amplifier stage between the balanced modulator and the power amplifier in my Roman WSPR DSB Direct Conversion transceiver. First I had to take the balanced modulator (trifilar transformer and two diodes in a singly balanced configuration) off the board and move back, closer to the AF input jack -- I needed to make space for the new amplifier stage. For that stage I consulted Doug DeMaw's books and Wes Hayward's EMRFD. I went with a feedback amp using a 2N3904 in Class A.

With coffee brewed and with my Drake 2-B tuned to the very congenial DX-60 net (75 meters AM on Sunday mornings), I turned to the junk box. It was like meeting old friends! I pulled out parts that Michael, AA1TJ had sent me. I pulled out others that had been sent by Jim, AL7RV. I got out my box of isolation pads that Jerry Felts, NR5A had sent in. Soon the parts were glued and soldered to a board that already had an AF amplifier designed by Roger Hayward, KA7EXM and a PA that is my "Manhattan-ized" version of Tony Park's SDR rig PA. At the center of the board is little Colpitts oscillator that I took from a WSPR rig designed by Gene, W3PM -- earlier in the week Gene had posted a comment on this blog saying he was pleased to see my call on his WSPR screen. I wonder if Gene realized that he was seeing the signal from an oscillator from his design! The laptop was provided by a listener who prefers to remain anonymous -- thanks OM! Nearby, a copy of "Lid, Kid, Space Cadet" by Jeff K1NSS provided encouragement.

The rig passed the smoke test so I moved it over to the operating position and put it on the air. I got immediate gratification: the WSPRnet map right away showed my signal (now around 200 milliwatts) being received all round North America. You can watch this LIVE by going to http://wsprnet.org/drupal/wsprnet/map Just plug N2CQR into the "Call" box and hit UPDATE.

I know that WSPR is not everyone's cup of tea, but I like it. It was fun to build this rig. While WSPR is almost exclusively a mode that uses store-bought equipment, I get a kick out of being one of very few ops using a homebrew transceiver in this mode. (Are there any others?)

Next steps: I need to figure out how to set up automatic switching (by the computer) from transmit to receive. And I want to make some PSK-31 contacts with this rig.

Thanks to all who contributed!

73 Bill

The Last Roman Rig: New WSPR DSB Transceiver

They are coming to pack up my soldering iron next week, so I'm afraid this will be my last Roman creation. You can see the W3PM Colpitts oscillator in the center. The KA7EXM AF amp is in the lower left. The Softrock-based Manhattanized PA is in the upper right. To the right of the oscillator is a classic W1FB two diode balanced modulator. You see three big green relays. The top one switches the antenna and 12 volts during T/R switching. The middle one switches the audio amp input, the bottom one switches the audio amp output. (I use the same AF amp for receive and transmit, just switching around the input and output.)

It works fine and has sent and received WSPR sigs. I think it will also do PSK-31 with the FLDIGI program. I could use a one more stage of RF amplification between the balanced modulator and the PA driver amp. Also, the AF impedance match between the KA7EXM amp and the balanced modulator nees work: Roger's circuit was deisgned to drive high impedance phones. That balanced modulator circuit has about 50 ohms at each port. Ideas?

I was thinking of calling it the Achilles. But I think I will go with "L'Aquilone" (The Kite").

Above Board: Manhattan-izing an SMT kit

A while back, Tony Parks very kindly sent me one of his wonderful Softrock RXTX V6.3 Software Defined Radio kits. I took a shot at it, but it turns out that I'm not very good with surface mount construction using small parts. I've gotten very used to the Manhattan style. Still, I did manage to build one of the Power Amplifier modules, and I put it to good use in a DSB WSPR transceiver I've been building (see above) . It worked great. For a while... Then it released some smoke.

I started trouble shooting and it was at this point that I REALLY began to miss good ole' Manhattan (you see, I was born there, and I went to Manhattan College, so I guess this helps explain the affinity). It was difficult to get to components mounted under the board. The whole thing was the size of my thumb... I know, whine, whine, whine... Luddite Geezer-ism strikes again. SPARK FOREVER!

It turns out that the problem was caused by the fact that my shack is just not well suited for this kind of construction. There is a lot of stuff floating around. Conductive stuff. Look closely at the picture below and you will see what I mean. You will see what caused the release of the smoke. Look at the leads on the PA transistor on the left. That's a little bit of stray wire that found its way to the WRONG place. Note the toasted source resistor just below!

Anyway, after a trying to fix this thing, I finally gave up and decided to use the circuit, but in Manhattan form. Everything up top. No SMT. Bigger coil cores. The temperature sensing circuitry went off to the right. The output transformer went off to the left, and the driver stage went down below the kit's board. Here is what it looks like now. Again, it works great.

I want to thank Tony and the Softrock guys for giving me this experience. Their kits are wonderful and are really making a tremendous contribution to the hobby. I strongly recommend them. The instructions are great, much like those of the old Heathkits. But for me, I'll take Manhattan.

YET ANOTHER HB DSB QRP WSPR Station! And more "inverted FSK"!

Paul, M0XPD, reports that he has joined the DSB revolution and has put a homebrew DOUBLE Sideband WSPR signal on the air. The rig is pictured above. So I can no longer claim to be the ONLY DSB WSPR station in the world. FB Paul. For more details go to Paul's site:
http://m0xpd.blogspot.com/2010/05/homebrewed-whispers.html

This was the second time in a week that I've found someone else doing the same nutty thing that I've been doing. The first incident involved G0XAR. I found him transmitting upside down FSK on 30 meters. Again, I am no longer alone...
Note that both of my colleagues in radio eccentricity are from Britain, a land that takes justifiable pride in its eccentric boffins!

Receiver Success! Combining Computers and Homebrew Radio

Well, it turns out that yesterday was a GREAT day for a new receiver. When I got home from work 30 meters was open. I fired up the new receiver and the FLDIGI program. Immediately I started to see and decode PSK-31 signals. I quickly switched over to the WSPR program and right away I could see the little two minute WSPR sigs. Here is what my screen looked like:

The program also began to automatically upload reports to WSPR HQ. Here is the report I found on the WSPR web site this morning:

I know all this WSPR and digi stuff often seems to be very computer-centric, and very "appliance radio," but I think this little project shows how we can have the best of both worlds: This rig combines a laptop computer and some pretty sophisticated software with a VERY simple, discrete component, homebrew direct-conversion receiver.

OK. So you see that I left a lot of space on the PC board. That's where the DSB transmitter (for WSPR and possibly PSK-31) will go.

BTW: You can keep an eye on my reception reports by going to the Database section of the WSPRnet site and plugging my call (I0/N2CQR) into the "reporting station" block. I'll leave the receiver on today.

A Bad Day for a New Receiver

Here is the latest picture of my version of the W3PM WSPR receiver. You can see the Ugly Weekender AF amp in the upper left. No front end of any kind yet -- the sig goes right from the antenna jack into the RF pin on the SBL-3 diode ring mixer.
Turns out that this morning was a bad time to test a new receiver. Spaceweather.com reports that a big coronal mass ejection hit earth today, causing havoc in the ionosphere. I'll try it again later today.

G0UPL's Ingenious QRSS Circuit

Just look at that circuit! That's a complete QRSS beacon transmitter, including a multivibrator (the two transistors on the left) to generate a recognizable pattern on the grabber screens. This diagram appears in SPRAT 134. Hans Summers ran this rig with just a couple of volts from his homebrew bleach-based battery system back in 2008. I plan on putting a version of this rig into the solar powered lawn lamp I showed you two posts ago (scroll down).

In other news, I finished building the Ugly Weekender AF amp this morning, and it passed the smoke test. My WSPR system went toes up this morning, so today I am QRSSing on 30 meters. I'm running my usual upside down FSK. Please let me know if you see me.

Colpitts Mania! Two Rigs Under Construction

I'm really into Colpitts oscillators lately. I blame Gene, W3PM. He reminded me of the fact that these little one transistor stages can pump out the 7 dbm needed to drive a diode ring mixer. Gene sent me a note warning that I'd have to take special precautions to ensure stability, but I found that this circuit never strayed more than 20 hertz in the course of a full day of oscillating.

Above you can see my version of the Colpitts circuit that Gene has in his very nice WSPR transceiver. You can see the SBL-3 diode ring mixer above the oscillator in this picture. I still haven't decided on the audio amplifiers.

I'm working on a second Colpitts circuit. This one is for a QRSS transmitter, also for 30 meters. Here I took my inspiration from Michael, AA1TJ, who has been working DX with power levels similar to that of this little oscillator. Long-time blog fans might recognize this board, or at least the device that it was used in. This is the board from my "DaVinci Code" 30 meter frequency standard, so called because I used a paperback copy of the Dan Brown novel as insulation for this weird piece of test gear. With my Kempton Park Frequency counter working, I had no need for the DaVinci device. But the oscillator was a Colpitts, capable of pumping out 10 mW all by itself... I plan on building a Hans Summers-style multivibrator circuit to put a distinctive pattern on my QRSS sig. It should fit nicely on the same board. I have a case and a power source in mind: see below. See if you can figure out where I'm going with this.

Success! Uganda WSPR Station On The Air!

Isn't it beautiful? Like an RF palm tree rising out of Uganda. That's a map display of the stations that have received the WSPR signals of 5X7JD in the last 24 hours. Not bad considering that Jack's rig is running one watt and that we are in the midst of a pretty massive geomagnetic storm.
This is a beautiful story for several reasons: Technically, the rig is very elegant. But even more appealing is the human aspect of this operation: This is a real "International Brotherhood of Electronic Wizards" story. First, Jack Dunigan goes to Kampala to help kids who are struggling with AIDS. Then Gernot, OE1FM, jumps in and designs and builds an ingenious rig that will allow Jack to run a WSPR beacon from Uganda. For more details, check out Jack's web site: http://hamradiosafari.com/ I got a kick out of his mention of a certain station in Rome that is running a 200 mW WSPR beacon. (And I'm looking forward to Jack's article on Kampala's "Radio Row" -- I suspect it will be a lot like Santo Domingo's.) Three cheers for Jack! Three cheers for Gernot! Three cheers for Joe Taylor! Three cheers for the International Brotherhood of Electronic Wizards!

Geo-Magnetic Storm! Aurora as seen from orbit

Batten down the hatches my friends. The solar wind is blowing, and we're in a geo-magnetic storm. Well, we were anyway, yesterday. Astronaut Soichi took this amazing picture of the resulting aurora.
No WSPR spots of my little signal this morning -- I blame it on the storm.
You can see some interesting discussion of the storm conditions on the WSPR live-chat system. Here is a sample of last night's commentary: