Author: Peter Marks

SV3ORA’s Amazing Homebrew Web Site

Kostas Giannopoulos has a lot of really great homebrew information on his QRP web site. It is reminiscent of the JF1OZL site. Check it out: http://www.qrp.gr/index.htm

For an example that his apropos of recent ET-2 discussions, Kostas has an extensive page with many, many versions of his hyper-minimalist rig:

Link to this project: http://qrp.gr/allbandtrx/
Thanks to Kostas for putting together such a great site. And I really like the name of the site: Discrete Electronics. FB.

SPRAT, the FETer, DLR headphones, and recent QSOs on the ET-2

Yesterday we had QSO #13 on the ET-2. This was with Jim W1PID. In an earlier contact Jim told me I had some chirp. I fiddled with the coupling cap and the bias pot and am now T9! These days, chirp is an endearing, nostalgic problem to have. Thanks for the report and QSOs Jim!

Contact #9 was with Fred K9SO. He is in Wisconsin and QRZ.com put our distance at 633 miles. That is our DX record so far. Not bad for 92 milliwatts to a dipole on 40 meters.

Most of my contacts come as a result of pleas for assistance on DX Summit or the SKCC Sked page. But I did make one “random” contact: Contact #6 with N2VGA. He just heard my CQ and gave me a call. FB.

I checked to see if OM Glen Yingling W2UW — the guy who started all this with his ET-1 — is still around. He became a silent key in 2012. But his ideas live on…

SPRAT 137 (Winter 2008/09) has a great article by QRP hero G3XBM. Roger built a version of the ET-1. His was for 80 meters and he called it the FETer. FB. I was struck by his estimate of the sensitivity of the ET-1 receiver: -100 dbm. I measured the N0WVA receiver (the one that I am using) has having a minimum discernible signal of -93 dbm. Pretty close. We may be at the limit of what you can expect from a single transistor receiver.

SPRAT 137 had something else that really resonated with me. G3YVF had an article on a minimalist rig using only one 6V6 tube. Geoff opened the article with this warning “Don’t try this unless you have a set of balanced armature type DLR ‘phones as they are really sensitive.” I have a collection of old headphones that I picked up at hamfests in London years ago. When building the ET-2, I checked all the old phones for sensitivity. A set marked DLR was the most sensitive. So Geoff’s observation had been independently confirmed. QRP Quarterly had an article comparing the sensitivities of old headphones — we should dig that article up.

SPRAT #137 is a reminder of what a great resource SPRAT — The Journal of the GQRP Club — really is. As we say on SolderSmoke, if you are not a SPRAT subscriber you are just wrong! Here is how to join GQRP and subscribe to SPRAT: http://www.gqrp.com/join.htm

The ET-2 with Callsign Tattoos

Slots are still available!
Get your callsign on the ET-2!

This rig will probably soon turn into wall art here at SolderSmoke HQ. With this in mind I have started writing on the wooden base of the rig the callsigns of all stations worked. So far we have 10. There is space for more.

Frequency is 7038.6 kHz. I usually try for contacts around 1430 UTC (0930 Eastern) and again at around 2130 UTC (1630 Eastern). I post messages asking (pleading!) for assistance on the DX Summit site and on the SKCC Sked board.

If you are within reasonable range for a signal in the 100 milliwatt range (antenna is either 40 meter NVIS dipole or a doublet) please keep an eye on the DX Summit and/or SKCC sites and maybe try to have a contact.

Background on the rig here:

https://soldersmoke.blogspot.com/2019/10/more-on-et-2-better-pictures-and-more.html


For All You Guys Who DON’T Use the Proper Fuse Value

Pete has been trying to talk sense on this issue for a long time, but some folks just won’t listen.
You need to have a reverse polarity protection circuit in your rigs AND you need to carefully determine fuse size needed for normal operation. If your final transistors for some reason start pulling more than the normal amount of current, the fuse will blow before your PA transistors release their smoke.

Melbourne Australia — QRP By the Bay 2019

Each November, Peter Parker VK3YE and his ham colleagues from Melbourne share with us reports on Peter’s annual “QRP by the Bay” event.

I think VK3HN should seek a trademark for that hat. As soon as I saw it on the table in the video above, I knew these were Paul Taylor’s rigs. FB Paul. Here is Paul’s report:

https://vk3hn.wordpress.com/2019/11/02/qrp-by-the-bay-chelsea-beach-melbourne-2nd-nov-2019/

Great work guys. Thanks a lot. 73

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




Direct Conversion (videos)

Here are a couple of videos from 2017 (never posted before). I built a little 40 meter Direct Conversion receiver for my nephew John Henry.

Whenever we work on circuitry like this, we should be be grateful for Wes Hayward W7ZOI who, in a 1968 QST article, reminded us of this important but until-then forgotten technique.

More information on this project appears in these links:

https://soldersmoke.blogspot.com/2017/10/a-direct-conversion-iphone.html

 https://soldersmoke.blogspot.com/2017/11/iphone-direct-conversion-receiver-with.html

Minimalist Masochism at Solar Minima — But More Contacts with the ET-2

Dylan Thoams

“Rage, rage against the dying of the light”

I thought of that line from Dylan Thomas’s poem when I read on G3XBM’s web site that we are kind of at the very bottom of the solar cycle. Roger wrote on 22 October: “Solar flux is 64 and the SSN 0. A=5 and K=0. As far as I am aware this is the lowest solar flux this solar minimum.”

I also thought of this as I pounded brass (Indian brass!) in an effort to make a few more contacts with my ET-2 two transistor rig. Obviously venturing forth on 40 meters with just TWO transistors (one for transmit and one for receive) and crystal control AT SOLAR MINIMA is not for the faint of heart. It is almost a Dylan-esque act of defiance.

I have had to resort to pleas for help on the DX Summit, the SolderSmoke blog, and the SKCC Schedule page. Fortunately for me, the brotherhood has sprung to my support.

W1PID (who gave me contact #3) also gave me contact #4 on 21 October.

W4KAC in Hickory NC was contact #5. This was on 22 October. This was the only marginal contact so far. He was running 5 W into an end fed half wave.

Yesterday was a big day for the ET-2. I had two solid contacts:

#6 was N2VGA in New York UPDATE: Larry N2VGA confirmed by e-mail that this was a “random” contact — not the result of my on-line pleas for assistance. He just heard my CQ and responded. FB.

#7 was K4CML in Newport News, Va. He switched to QRP himself at 2.5 watts for a nice 2X QRP contact.

Looking at my Rigol ‘scope, I now think I’m putting out about 150 milliwatts. Not bad for a single J310. I may have to invest in a heat sink.

40 seems most cooperative in the morning (around 0930 local) and again in the afternoon (around 1630 local).

Thanks to all who have helped. I will try to make a few more.

Farhan Visits Northern Virginia and SolderSmoke HQ

Our good friend Farhan came to Northern Virginia last week for the 50th Anniversary Symposium of AMSAT. We were really delighted that he also came to SolderSmoke HQ. Elisa and I gave him a lightning tour of Washington DC (including a quick visit to The Air and Space museum) and then we headed back to the shack from some radio work.
In the picture above you can see my BITX-20 (that Farhan designed) off his right shoulder. Off his left shoulder you sits my ET-2 rig. I really wanted to show Farhan how well the N0WVA regen performs — he was impressed, especially when we started listening to SSB contacts. It was really amazing that we were doing this with just one J-310 FET. This was great fun. Farhan tells me that he will soon take up the “two transistor challenge.”
When he was here in 2017, I tried to demonstrate my version of Rick Campbell’s R2 Direct Conversion receiver. Unfortunately, when I tried to show off the “single signal” capability that is the whole purpose for this receiver, it was NOT producing a single signal output — you could hear the signal on both sides of zero beat. One of the small AF chokes I had used had gone open, knocking our one of the two DC receivers. This time I had the problem fixed and single signal reception was successfully demonstrated.
Farhan brought me two pieces of test gear that I have needed for a long time: A step attenuator and a two tone generator. Paired with his Antuino, these devices will bring about a big increase in capability on my bench.
It was really great to have Farhan in the shack. We had a great time talking about ham radio and homebrewing. Elisa and I both really enjoyed hearing from Farhan about his travels and about his life in India. We are all really lucky to be in the same hobby as Ashhar Farhan. Thanks for the visit Farhan.
Here is a quick video of Farhan tuning the BITX 20.

QSO #3 with the ET-2 Minimalist Transceiver

The Radio Gods were clearly supporting me on 16 October 2019. I had sent out a plea for people to listen for the 80 mW CQ from my ET-2 rig. I had specified 0930 Eastern as the time. Little did I know that there would be a contest at that hour (on a Wednesday morning!) on 40 meter CW. There was no chance of my signals getting through. I leaned that the contest would be over at 1000 hours, so I waited and called CQ again at that hour. Jim W1PID had guessed that I would do that. I immediately recognized his call — he was often at the other end of Michael Rainey’s most daring low-power adventures. He was a participant in the famous Rexpeditions, including a coastal effort to send Michael’s voice-powered CW signal across the Atlantic. His normal operating habitat is in the field. We had a wonderful QSO. He told me I peaked at S-6.
I have worked W1PID on at least two Straight Key Nights and this blog has had many postings about his long-standing involvement in QRP.
Thanks a lot Jim!

Please Listen for My 80 Milliwatt CQ Tomorrow, Wednesday 16 Octoberr

I will be calling CQ from Northern Virginia starting at 1330Z (0930 Eastern) on Wednesday 16 October 2019 on 7038.6 kHz with my ET-2 QRPpp rig. I have made two contacts so far — both contacts were at a range of about 300 miles. I’d like to be able to make at least one per day. If you are within range please listen for my CQ tomorrow and give me a call.

Thanks and 73 Bill N2CQR

More on the ET-2 : Better Pictures and More Circuit Description. Some Thoughts on Simplicity

So yesterday I made my first contact using my ET-2 rig. Last night I got an e-mail from Gary, the fellow at the other end of that contact:
Evening Bill, N2CQR….Yes I did learn about you from the spot on the DX Summit cluster. I tuned to the freq to see if I could even hear your 80 mW and you were a good real 569 when calling CQ. You built up to a real 589 on the later transmissions. I did not have either of the two pre-amp positions on in the ICOM 756 Pro II. There was not any QRM on the freq either. Your spot indicating the 80 mW is what really got my attention.
My antenna is a 2 element yagi at about 115 ft and it really works great for me.
Thanks for the picture of the great little transmitter. Glad to be your first DX QSO with it. Hi Hi Maybe again soon. My pleasure to work you.
73, Gary, K4MQG

Fort Mill, SC

Farhan commented on yesterday’s post, saying that it was hard to tell (from my pictures) where he rig started and ended. He was right. So this morning I have tried to clean up my bench a bit — I hope these pictures are better.
Above you see the whole rig. The transmitter board is right next to the key that Farhan gave me. You can see the 7040 crystal. A C-Clamp holds to the bench the piece of scrap plywood that serves as the base for this rig. Next to the C-Clamp you see the TR switch — the just switches the antenna — both transmitter and receiver are powered at all times. I can hear the transmit signal in the headphones and this serves as my sidetone.
Here is a close-up of the transmitter with the schematic below:

The transmitter is VERY simple. Nine parts, including the low-pass filter. You can barely see the J310 FET to the right of the crystal.

Here is the receiver:

I really like N0WVA’s regen. The green diode in the source circuit is the key. This one does not squeal when you go into excessive regeneration (when you think about it, regens should NOT squeal at audio frequencies — but most do). Also, the green diode dims a bit when you are at the right amount of regeneration. In the picture you can look down the tube of the variometer that Pericles HI8P gave me many years ago. The big variable cap is from the junk box — I think it may be from a Johnson Viking transmitter. Note the long shaft with the insulating connector — this is to reduce the hand capacity effect. On the right you see a smaller cap with just one vane — this is my fine tuning control — with the smaller cap at mid range, I would just set the big capacitor to put the receiver at 7040 — with the smaller cap I could tune +/- 12 kc. I also used an insulating shaft on the smaller cap — the connector for this one is from an old 1930s era regen that I picked up at the Kempton Part rally in London.

Instead of the audio transformer and Radio Shack headphones, I just used some old DLR-1 WWII Headphones. They are very sensitive and work well.

Lots of soul in this new machine: The variometer from Pericles. The WWII headphones. The 1930s era shaft connector. The circuit idea from the Autumn 2001 SPRAT. Farhan’s key.

I recently read on Hack-a-Day of a new FPGA chip that has on it 35 BILLION transistors. I’m sure that thing can produce some fascinating results, but can anyone really understand it, or feel that they really BUILT something that has that kind of chip at its center? On the other hand, I did rely on a lot of modern digi technology in this project: The Reverse Beacon Network reported back that my unanswered CQs were in fact getting out (one as far as Kansas to K9PA). And in the end I had to ask — via the DX Summit Spotting cluster — for someone to listen for me. So I can’t go full Luddite here. And I wouldn’t want to have to use a rig this simple every day. No way. It is just too hard to use. But there is a beauty and a challenge in simplicity. There is some virtue in using just two transistors instead of 35 billion.

Thanks to N0WVA, W2UW, VU2ESE, HI8P, K4MQG, The G-QRP club and their inspirational journal SPRAT, the RBN and the DX Summit.

Success with my ET-2 –TWO TRANSISTOR RIG

In my effort to replicate the ET-1 rig of Glen Yingling W2UW, I had a hard time getting the receiver to work well with the single FET being switched between receiver and transmitter, so I retreated a bit and went with individual FETs for the TX and the RX. This doubled the transistor count — to TWO. So it is an ET-2.
I also boosted the power to 80 milliwatts by putting 12 V on the transmitter. The receiver was running off the 9V battery you can see in the left in the picture.
Here is the story of the contact:

To K4MQG from N2CQR:
Gary: Wow thanks for the QSO today. I was using 80 mW transmitter that consists of just 8 parts! The receiver was a regen using one single transistor. So one transistor on transmit and one transistor on receive. And it reached South Carolina.

I was about to give up hope. I had been calling CQ for days. Then I was talking to Rob VE4GV on 20SSB. Rob suggested that I “spot myself” on one of the DX clusters. So I did (see below). Obviously you saw my spot and a minute or so later, SUCCESS! I’m really pleased.

Attached is a picture of the rig. The transmitter is around the crystal and the blue pot on the right. The headphones are from WWII. The receiver was powered by the 9V battery. The regen uses a variometer given to me by a friend in the Dominican Republic in 1992. The main tuning dial is connected to the cap by an adapter from a 1930s-era regen. Antenna was a 40 meter dipole at about 25 feet. Obviously your 3 elements a 115 feet were doing the heavy lifting.

Thanks again Gary!

And thanks to Rob for the suggestion on the spotting.

73 Bill N2CQR

The BGCD: A Regenerodyne Receiver built on Pencil, Candy, and Tea Tins. Circuit from 1937 QST

David Newkirk recently put up a nice website on ham radio. The page below provides details on the amazing creation pictured above: The BGCD: “The Byron Goodman — Clinton DeSoto Regenerodyne.” It is a beautiful piece of work, made more beautiful by the metal containers used in construction: pencil, candy and tea tins. The circuit is based on a 1937 QST article.

David’s site reminded me of the wonderful writing of his father, Rod Newkirk of “How’s DX” fame. More on him in due course.

 More on the BGCD here:

http://dpnwritings.nfshost.com/ej/pictures/pictures1.htm?fbclid=IwAR2-lmJ8E1kEBT_jsB3Q8UnPaN0vc472dP783ifABK7eSxgpe5M1Pl0N77g

Very Useful: Copper Tape with Conductive Adhesive

This copper tape is really useful, especially when doing “free style” homebrew. At first I didn’t even realize the adhesive is conductive. This tape is great for creating a common ground among several printed circuit boards, especially when you are using a wood board as the base. You can solder to it very easily. You could even use it (with a wood or plastic base) in lieu of a copper clad board. Lots of possible applications for homebrewers. This stuff deserves a place on the workbench shelf right next to the Gorilla Tape and the Crazy Glue. I’m using it in my Single Transistor Rig project.

You can get it from Amazon — there are many varieties and vendors. This one is similar to the one I am using.

https://www.amazon.com/dp/B01I1XNY1E?aaxitk=I9X2Na8Gu23M3nrhlpSzYw&pd_rd_i=B01I1XNY1E&pf_rd_p=44fc3e0f-4b9e-4ed8-b33b-363a7257163d&hsa_cr_id=3252618550401&sb-ci-n=asinImage&sb-ci-v=https%3A%2F%2Fm.media-amazon.com%2Fimages%2FI%2F71sJrx27%2B-L.jpg&sb-ci-a=B01I1XNY1E