First QSO with the High-School Receiver -- 100 mW to Dipole. (with videos) -- Homebrew to Homebrew!

  

Alan W4AMV in Raleigh NC

Dean KK4DAS and I have been working with a local high school.  The students are building a direct conversion receiver for 40 meters.  

We've been giving out prizes for the first team to complete each stage.   I wanted to give one of the teams a little oscillator that could b heard with their receiver.  So this morning, using a 7040 crystal from the AF4K (SK) company, I threw together a one transistor oscillator.  It has just 8 parts, including the key:

https://makerf.com/posts/ten-minute-transmitter  

I had a low pass filter in the antenna tuner.  The antenna was a low-to-the-ground 40 meter dipole.  The transmitter was putting out around 100 milliwatts.   

N2CQR's Ten Minute Transmitter

The Reverse Beacon Network showed that I was getting out quite well: 

Then I thought, wait a second, let's make a contact with the prototype high-school direct conversion receiver.  

With the receiver hooked up, I again called CQ on 40 CW.  BOOM!   Very quickly Alan W4AMV in Raleigh NC  came back to my call.  Wow!  That's 222 miles.  And a quick check of QRZ.com revealed that Alan is a homebrewer.  Then Google reminded me that his work has been featured on the SolderSmoke blog.    TRGHS. 

I was so excited during this contact that I almost forgot to film it.  But I did manage to get some short clips of the QSO in progress.   You have to listen carefully, but you can hear our calls in there while Alan is transmitting (listen for the lower tone): 

(83) W4AMV as heard in DC RX - YouTube

And in this clip you can watch me transmit using the 10 Minute Transmitter: 

(83) N2CQR transmitting with 10 minute transmitter to W4AMV - YouTube

UPDATE (Feb 27 2023):  I asked Alan about the rig he was using:  "A PLL EXCITER DRIVING A PAIR OF FETS PUSH PULL ABT 50 w to an inverted L at 55 feet. The Rx a single conversion 9 MHz IF and it is connected to an active antenna in the trees out in the woods abt 25 feet up. Uses an automotive whip antenna about 3 feet long. "

Alan's Rig

This little contact is a reminder of the fun that can come from using simple, homebrew, QRP gear.  It is really amazing that the very first contact with this receiver was with another homebrew station.   This all reminds Dean and me of something we have been telling the students:  the little DC receiver they are building is not a toy -- it is capable of being used in real, long-distance contacts.

Thanks Alan!    

On Ten Meters with a uBITX from the Eastern Tip of Hispaniola

On ten from HI7.  Cluster spots, DX, CW, and the Reverse Beacon Network. 

 

Santo Domingo Shack on 12th Floor Balcony -- SST QRP CW

June 2021.  We were in Santo Domingo, Dominican Republic.  At this point we were in a 12th floor apartment in the center of the city.  I would take my SST 20 meter CW transceiver and EFHW antenna out on the balcony.  I made no contacts from this location, but one of  my CQs was picked up by K9TM on the Reverse Beacon Network (see below).  All the other RBN spots were the result of calls from the eastern tip of the island. (Click on the RBN image for a clearer view.)

 

KK4DAS Michigan Mighty Mite Heard by WEB SDRs -- CBLA Mobilized!

Dean KK4DAS continues to do great things with his Michigan Mighty Mite.  He has been calling CQ on the Color Burst Liberation Army (CBLA) frequency of 3579 kHz.  I think I was the first one to hear him, but since that memorable moment he has been picked up by multiple Web SDR receivers, including the one at Penn State (PETE JULIANO'S ALMA MATER!)  (screen shot above, listen by clicking URL below).  He has also been heard by Web SDRs in Concord Mass,  Newport News Va, and Cleveland, Ohio.  FB Dean.  

So come on folks -- this is a mobilization call for the CBLA!  Get those MMMs on the air.  Send us reports and recordings from Web SDRs or the RBN. 

Listen to Dean's MMM as received at the Penn State Web SDR: 

http://soldersmoke.com/KK4DAS MMM.wav

It sounds great!  And nice CW Dean!  

Dean KK4DAS Puts Michigan Mighty Mite on the air! And is heard in Falls Church, Virginia! (video)

QRZ.com says we are 5.9 miles away.   The U.S. Postal Service almost prevented this from happening -- they objected to my just putting the crystal in an envelope and mailing it.  Dean's wife had to pay postage due.   

The rig didn't work at first, but Pete N6QW provided sage advice and tribal knowledge.  Adjustments were made and Dean experienced the Joy of Oscillation.  Then, he connected an antenna and was heard at the SolderSmoke East Coast HQ. 

Obviously the beret was the key to Dean's success: 

This was a lot of fun.   And it is a reminder of the power of the MMM.   Dust off those Mighty Mites!  Call CQ and see if you can be picked up by the Reverse Beacon Network.  Let us know if you succeed.   

Getting ready

Done!  Dean's MMM

My QRPp Signal Arrived in Utah -- 100 mW, 1950 miles, 26 db Above the Noise!

So yesterday morning I was calling CQ on 40 meters with my ET2 two-transistor 100 mW rig.  Later, I took a look at the Reverse Beacon Network (RBN).  Among the East Coast skimmer stations that regularly pick me up I saw an  outlier:   WA7LNW in Utah.  He's 1950 miles from me. And the RBN reported that his receiver had me at 26 db above the noise.  

Here is a screen shot of the RBN report.  Note the time: 1234 UTC.  Around sunrise here -- so gray line conditions.   

But the really BIG factor explaining that 26db s/n ratio is WA7LNW's location: 

"Realtime spots are being received at this location and uploaded to the Reverse Beacon Network."

"CW Skimmer antenna is located on cliff edge overlooking the Virgin River Valley, 1,200 ft. below."

We reported on the WA7LNW RBN station back in 2013:  https://soldersmoke.blogspot.com/2013/03/edgy-skimmer-antenna.html

Check out Jack's QRZ.com page: 

https://www.qrz.com/db/WA7LNW

RBN is an important resource for QRPers and homebrewers.  Three cheers for Jack and all the skimmer stations.  Thank you all.  

SolderSmoke Podcast #214 is FINALLY out!

WE ARE WORKING TO IMPROVE THE AUDIO QUALITY.  IN THE FIRST RELEASE OF THIS PODCAST SOME OF THE AUDIO WAS KIND OF MUFFLED.  I TRIED TO FIX IT THIS MORNING AND I THINK I MADE SOME IMPROVEMENTS.  THE IMPROVED AUDIO IS NOW AT THE LINK BELOW.  

4 November 2019 (shockingly late!)

http://soldersmoke.com/soldersmoke214.mp3

The visit of Farhan to Northern Virginia
"I heard this guy from Southern California on 20..."
Fire Report from Pete

Pete's Bench Report
"When you know stuff, you can do stuff!" 
The CRAP rigs 
Old Boatanchors -- the Swan 120  with SUPER STABLE ANALOG VFO! 
Ten Tec rigs dial cord replaced with Chinese digi sig counter 
Pete's 500 mW encounter with a QRO curmudgeon
The ZL2BMI Challenge has Pete building crystal filters
The Left Coast Loafer CW rig 

Bill's Bench Report

ET-2 Refinements
N0WVA's Regen Receiver 
Going from ET-1 to ET-2
J-310s vice MPF-102
100 mW from a single J-310
Receiver kind of deaf -103 dbm MDS
10 contacts so far in 9 states 
THREE contacts yesterday.
Worked Wisconsin - 633 miles on 92 mW 
We are at sunspot minimum. 
"Rage, rage against the dying of the light." 
Simplicity is the real reason for CW 

IDEA:  Get those Michigan Might Mites on the air! 
Use Reverse Beacon Network to see if you are getting out 
Use SDR receivers to make contacts

MAILBAG
DL1AJG
KC6SAX
W9VNE
KA4KXX
N0WVA
Zl2BMI
AJ6BD  

ONE VOLT rms Reaches New Hampshire from Virginia

 My son Billy was back from college over the weekend (he came back to help me celebrate the completion of yet another orbit of the sun).  I was showing him my 8 part rig and telling him that it puts out 20 mW.  He asked a good question (he is a scientist):  What is the voltage at the antenna terminal.  I checked:  ONE VOLT rms.   About 1.414 volts peak.  Think about that.  My transmitter is sending a signal to New Hampshire from Virginia on less than the voltage of  AA battery.  

Two more spots on the Reverse Beacon Network (see above).  Another skimmer station in New Hampshire.  My signals seem to like the granite state. 

Smoke-Free! On the Air with the W1REX Dayton Hamfest Buddy

After the Dayton Hamvention, our ace correspondent Bob Crane (W8SX) sent me the "Hamfest Buddy" kit that Rex Harper W1REX had put together and used in "The World's Biggest Build-a-Thon."

It is a single 2N2222 crystal-controlled oscillator for 20 meters.   All the parts are plug-in -- no solder smoke is released.   Mine went together in about 15 minutes and fired right up.  You can see it above.  It runs off the 9V battery. I had to hold it down with tape.   You can see the key button in the lower right.  That little inductor in the foreground is used to shift the frequency a bit.  I had to remove the 10K resistor in the emitter circuit because with my antenna the circuit was going into low-level oscillation even in key-up.  With the 10K resistor removed, this problem disappeared.

I hooked it up to my 20 meter dipole and called CQ.   With only about 60 milliwatts into a dipole under poor conditions, I really didn't think I'd get any answers.  But I figured the Reverse Beacon Network might pick me up.  It did:

Thanks Bob!  Thanks Rex!

Arduino, K6HX's code, and an RBN (minimum) speed limit?

 

Hello Mark:  I've been using your code.  Very nice.   Easy to use and modify, even for a digital dunce like me. 

 

I've been using an Arduino and your code to key my 20 meter QRP transmitter.  I watch the Reverse Beacon Network to see how I'm getting out.  I think  your code let me discover something about RBN:  there may be a lower "speed limit" on the skimmers.  I noticed that when I left your code at the default 12 wpm, I was not picked up by the skimmers.  When I called CQ the old fashioned way (with my hand!) at 15 wpm I got plenty of spots.  This morning I changed the speed setting on your code to 15 wpm and -- sure enough -- immediately got picked up by an RBN station. 

 

Anyway, thanks for the code and for your Brainwagon blog. 

 

73  Bill  

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Edgy Skimmer Antenna

For the last few days I've been hanging out on 20 meter CW, 14.050 - 14.060 MHz, using my re-built W1VD/Barbados rig.   I've had some great contacts, but almost as  much fun is watching the Reverse Beacon Network to see who is hearing my calls.   WA7LNW is one of the "skimmers" that most consistently picks up my signal.  One look at the picture above explains this.  The receive antenna for his skimmer rig IS ON THE EDGE OF THIS CLIFF!   Jack has one of those dream jobs for a radio amateur:  he works at that amazing location, testing ejection seats for jet aircraft.  More great pictures here: 

http://www.dxwatch.com/qrz/lookup.php?c=rbn/WA7LNW

Thanks for the reports Jack!

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

AA1TJ's Latest QRPp Rig

 

From Mike, AA1TJ:

I called CQ on 20m CW for a couple of hours yesterday afternoon with no response. With the cadence of my own Morse tugging at my eyelids, I was suddenly shaken awake by a brisk signal returning my call and signing CU2BV. I snapped out a 579 report and turned it over. The dits and dahs in my headphones told me it was Fernando; operating from São Miguel island in the Azores. He reported a weak but solid copy (529) of my fifty milliwatt signal.

Here's the radio that I used yesterday. The one-transistor transmitter is to the left of the red relay on the top board. The single transistor is a germanium surface-barrier device made by Philco in August of 1958. To the right of the relay is a two-transistor time-delay circuit used to switch the antenna between the transmitter and the receiver. My receiver on the lower proto-board is a reproduction of my first shortwave receiver: a $7 Japanese kit that I bought at Radio Shack when I was 13 years-old.

Fifty milliwatts is some twenty-four times less power than was used by an old double D-cell flashlight. I later learned that my signal was nearly simultaneously picked up by an automated receiver located just west of Dusseldorf, Germany.

Snowy Vermont to the lush Azores - some 1500miles off the coast of Portugal - with less power than is consumed by a beeswax candle...is it any wonder that I love radio? ;-)

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

WOW! The Reverse Beacon Network

In the European dispatches of Mike AA1TJ I saw mention of this new thing called the Reverse Beacon Network. Then SPRAT shows up in my mailbox (HOORAY!) and I see mention of the RBN there. So this morning I figured I'd give it a little test: I called CQ on 40 meters using my Heathkit HW-8. WOW -- it didn't take RBN long to get me! See above. That's after only about 3 minutes of CQing.

This is a really amazing and innovative development. The network makes use of "skimmers" that use Software Defined Radios connected to the net to search for CQs. When they hear one, they automatically post the info on the web. It is sort of like WSPR, but it is aimed at ordinary CQ calls. Fantastic. Check it out. You will like it!