Listen to the ET-2's Minimalist Regen Receiver

I'm guessing that most of you have never listened to a regen receiver that uses only one transistor.  So in these videos I've tried to capture the experience.  The audio that you hear from the receiver is from a small I-phone microphone taped to the one of the headphones on my DLR WWII headphones.  So you are hearing it just as I hear it -- with no additional amplification. 

Here is N0WVA's schematic.  When I tune the "regeneration" control I am turning the knob on the variometer.  The broad or "bandset" tuning control is essentially N0WVA's 25 pf cap.  My fine tuning control (the one that I use the most in the video) is the equivalent of the smaller cap in parallel with the larger tuning cap. 

I had trouble shooting the video for this post -- taping the mic to the headphone turned out to be a bit difficult.  So I ended up with a few extra (and imperfect) videos.  I include them here for anyone who might want to listen some more to a single transistor regen.  (I have a few more -- let me know if you'd like to see them!)



In the next one, at the end I throw the switch to transmit allowing you to hear what "sidetone" sounds like on the ET-2

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

Contact #10 with the ET-2 -- Perry K9NZ

Perry K9NZ was contact #10 with my ET-2 QRPp rig.   I found the above on his QRZ page.  Beautiful sentiments.  Most of us have similar stories, and similar feelings about ham radio. FB Perry.  

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  

Don't do this yourself...

...or else you'll be spending a LOT more time on 17 meters. 

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