Another Amazing SSB Rig: VK3HN's "Summit Prowler 6"

Here is another truly amazing compact SSB rig.   Paul Taylor VK3HN is a true homebrew wizard.  So many great homebrew rigs come out of Australia.   

More details: 

https://vk3hn.wordpress.com/2019/05/01/summit-prowler-6-a-pocket-sized-ssb-cw-transceiver-for-80-40-30-and-20m/

Paul's QRZ.com page: 

https://www.qrz.com/db/vk3hn

Paul Taylor VK3HN Talks about Hombrew and SOTA

 

https://www.youtube.com/watch?v=Rkd1o2PQI9M

It was great to see Charlie NJ7V of Red Summit RF interview Paul Taylor, VK3HN. 

Paul has been a friend for many years.  He is one of the FB ham radio operators and homebrewers from Melbourne, Australia.  

Paul has been on the SolderSmoke podcast and blog so many times, with so many rigs and so many summits: https://soldersmoke.blogspot.com/search?q=VK3HN

You should listen to Charlie's interview with Paul.  It is filled with good ideas and inspiration. 

Thanks to Charlie and to Paul. 

VK3HN's Inspirational AM Receiver (video)

I'm always delighted when I check the SolderSmoke blog and YouTube list (right hand column of the blog) and find a new post from Paul VK3HN.  And this morning's post is especially good. 

Paul has built an AM receiver. Above you can see his video.  Here is his blog post with details: 
https://vk3hn.wordpress.com/2019/12/06/8-band-superhet-am-receiver/

This is the kind of blog post that makes you want to heat up the soldering iron and start searching through the junk box.  I'm thinking about putting Paul's 6 kHz filter in my 40 meter HRO-ish receiver.  And I may make use of his AM detector circuit.  And maybe I can put that same receiver on 75 and 160... And then there are the SW broadcast bands... See what I mean?  

Thanks Paul.  73  

VK3HN: SOTA, HB, SSB, and QRP FB!

Peter VK3YE sent me the link to this amazing site.  Wow, Paul VK3HN does great work, both with the homebrew rigs and in describing his work on them.  Check it out: 

https://vk3hn.wordpress.com/2016/10/25/summit-prowler-one-a-homebrew-7mhz-ssb-qrp-transceiver-for-sota/

Great stuff.  Thanks Peter!  Thanks Paul!

VK3HN's Amazing Summit Prowler 9 Homebrew Transceiver - A Masterpiece of Miniaturization (VIDEO)

I was wondering what Paul VK3HN was up to. Now we know: the Summit Prowler 9 transceiver. 

This is yet another amazing rig by Paul, with GREAT documentation.   

I was impressed by those bandpass filters.  I will try to do something similarly robust on my 17/12 rig. 

Paul's miniaturization of this rig is really astonishing.  I would go nuts trying to keep it this small. I just couldn't do it. 

Look closely at the boards he uses.  They look like printed circuit boards, but with all the components and all the soldering on one side.  This is very smart -- this makes it easier to troubleshoot and to change components.  

I was glad to see at least one NE-602 in there.  FB. 

The video is above.  Check out Paul's blog for more info: 

https://vk3hn.wordpress.com/2021/02/27/sp-9-a-compact-five-band-ssb-cw-qrp-transceiver/ 

Thanks Paul!

VK3HN's Homebrew 30 Meter SST QRP Transceiver

It turns out that many people homebrewed SST rigs.  Here is Paul VK3HN's version.  Really nice. 

https://vk3hn.wordpress.com/2016/12/27/summit-prowler-two-a-scratch-built-30m-cw-transceiver-wilderness-sst-for-sota/

Oz QRP2QRP From Mt. Bullfight, Pyramid Hill, and Melbourne's Chelsea Pier

Paul VK3HN has obviously made an admirable effort here, and a visit to his very nice blog shows that he has a lot of true homebrew gear available.  We hope that he will haul some of that HB stuff up the mountain, perhaps to find Peter Parker operating from the Melbourne pier with a Beach-40.  As I type this I am listening to VK3IO on 40 meters, coming in nicely on my Barebones Superhet (kit version).

Dear Bill and Pete,

I would like to claim an entry in the SolderSmoke Homebrew To Homebrew
(HB2HB) log. Here's the story. On Sunday 24th April 2016 I drove two
and a half hours north east of Melbourne into the edge of the Great
Australian Dividing Range, to climb two summits, for the fun of
operating my 40 meter SSB QRP (5 watt) rig in a beautiful, RF-quiet
setting, and to activate two Summits Of The Air (SOTA) peaks.

My first summit was Mount Bullfight
(http://www.sotawatch.org/summits.php?summit=VK3/VN-002), in the
Rubicon Ranges, at 1,490 meters ASL not high by American or European
standards but a good heart-racing climb through thick Australian bush.
After a successful activation with good signal reports into Tasmania
(VK7), around Victoria (VK3) and New South Wales (VK2), I descended,
and drove about 2 miles up the valley to an adjacent SOTA summit,
Pyramid Hill (1,314 meters) where the activation also went well. Just
as I was finishing up with the chasers, Peter Parker VK3YE called me,
operating portable from his beloved Chelsea Pier, and we had a very
pleasant beach-to-summit ragchew QSO. The RF path is about 62 miles.

Peter was running his MDT double sideband rig, with 2 watts. I was
using my MST400, with 5 watts SSB. Both rigs are kit radios from OzQrp
(http://www.ozqrp.com/). Both are assembled by hams -- I built my
MST400 18 months ago and Peter was using the MDT rig that OzQrp
founder Leon, VK2DOB designed, built and kitted, the one he sent to
Peter for a YouTube review. So it was built by a ham, just not by
Peter.

Now, I know that there may be some, possibly even you Bill, who may
question the legitimacy of my claim on a coveted HB2HB log entry in
this particular case. I can assure you that we did experience the Joy
of QRP/P operation, Peter basking in the late afternoon Australian sun
on a beach and I on the mountain top. And to further add authenticity
to my HB2HB claim we discussed QRP, aerial experiments, and 'whats on
your bench' topics for a full 20 minutes.

However, I would not want to risk disturbing the wrath of the Radio
Gods with a dubious claim.

I admit that neither radio was scratch-built, on copper board
ugly-style, or had the form of a wild birds-nest of separate modules
and interconnections, with parts loosely screwed onto an Italian
chopping board or a discarded lump of wood. Indeed, neither can it be
claimed that both operators built their rigs. So I will take a
rejection of my request with acceptance and dignity, acknowledging
that you are duty-bound to maintain the highest of standards, and that
entry into the SolderSmoke HB2HB log is not to be granted without
proper consideration.

I do understand that you may feel that accepting this QSO could set a
dangerous precedent and risk opening the flood gates to a tsunami of
dubious HB2HB QSO claims from hams using minimal assembly rigs, like
some of the Elecrafts. Who knows, some individuals might even be
tempted to claim HB2HB QSOs from VHF FM hand-helds after managing to
screw on the rubber-ducky antenna. Even unboxing a shiny new
Yae-com-Wood is, to some, a form of 'handiwork'.

Bill, the decision is yours. Peter VK3YE and I look forward to your
decision. Judge wisely.

73 from down under, Paul VK3HN, with agreement to this claim from Peter VK3YE.

Details of this day of activations are on my blog at:https://vk3hn.wordpress.com/

Peter's MDT review is at:  https://www.youtube.com/watch?v=2OtZeFkb1xw

AM Diode Detector + 41 and 49 meter Shortwave Bands for HRO-dial Receiver (videos)

The COVID-19 emergency is a good time to look around the shack for projects you have been meaning to take on but didn't have the time for.  We have the time for them now! 

When I first built my HRO-dial receiver (using an HRO dial given to me by Armand WA1UQO and an enclosure from Tim KI6BGE)  my hope was to have the 40 meter ham band and some shortwave broadcast bands.  But it didn't work out that way.  I had trouble getting an AM detector to work properly, and I had a hard time getting a sufficiently broad filter to work right.  I ended up adjusting the VFO so that the receiver would cover only the 40 meter ham band.  

My recent S-38E adventures and a video from VK3HN have alerted me to the nice programming that is now on the shortwave broadcast bands (I really like WRMI's afternoon rock music program).  So I decided to take another shot at getting this receiver to cover SW BC frequencies. 

When I built this receiver, I made the front-end bandpass filter tune-able. There is a two section variable cap behind that "Pre-selector" control you see on the front panel.  That lets me tune two loosely coupled LC circuits from about 5.5 to about 8 MHz.  So without any mods to the front end, I could cover the 49 meter band (5.9 -- 6.2 MHz) our 40 meter band, and the 41 meter band (7.2-7.5 MHz)

Here is how I do it: 

For 49 meters:  I now have the VFO set to run from 6.34 MHz to 7.120 MHz.  The IF is .455 Mhz.  So to get down to the lowest frequency in the 49 meter band, I tune that front end preselector down to that frequency (variable cap in filter almost fully meshed).  Then I take the VFO down to 6.355 Mhz.  I take the difference frequency out of the mixer -- .455 MHz.  

For 40 and 41 meters:  I just tune the pre-selector to this range (variable cap about mid-range) and tune the VFO accordingly.   For a signal at 7.5 MHz, for example, I put the VFO at 7.045 MHz.  7.5 - 7.045 = .455 Mhz.  Note:  There is no sideband inversion in this case -- this is important because 40 meter SSB is lower sideband.  The Kokusai mechanical filter that Pete N6QW gave me is a lower sideband filter.  I have my BFO set at the right spot relative to the filter passband for LSB.

As you can see, I just tune to the "image frequencies" with the preselector.  This gives me double the frequency coverage.   

As for the filters, well Pete's Kokusai filter works great on 40 SSB.  My problem was,  ironically, getting a filter that was broad enough to let AM sound good.  I concocted a filter using old 455 kc IF cans, but I wasn't happy with it.  Paul VK3HN used a ceramic .455 MHz filter that was 6 kHz wide at 6 db down. I ordered some from Australia.  That should have been wide enough for AM, but I had gotten spoiled by the very WIDE bandwidth of my S-38Es (no real filters at all, just the two 455 kc IF cans).  At this point The Radio Gods interceded. Bruce KK0S heard me talking about this on the podcast and kindly sent me some 10 kHz .455 kHz filters.  Now we're talking!  I put one of them in this receiver and AM started sounding as good as it does in my S-38E.  BTW -- a look at NA5B's WebSDR receiver shows that most of the SW broadcast stations are running at 10 kHz wide.  See video below: 




Finally,  I had to get a decent AM detector going.   The SBL-1 product detector I have in there works great, but I had tried several AM detectors and none of them worked well for me.  This was puzzling -- it should be so simple, right?  Just a diode.  But I would get weak and/or distorted audio.  I realized that I really needed was something that looked to the rest of the circuitry like an SBL-1, but with just a diode and an RC filter section instead of the SBL-1's diode ring.  I ended up using a small 455 kc IF transformer that Michael Rainey (AA1TJ) had sent me a long time ago.  My detector looks like this: 

It works great.  During the day I can hear the Toronto CFRX talk-radio station that simulcasts with 1 kW on 6.07 MHz. In the evening I her WBCQ and many other stations on 41 meters (see videos).  And of course I am ready to use it for amateur AM signals on the high end of the 40 meter phone band.   

There is a lot of soul and friendship in this receiver: 

-- HRO dial from Armand WA1UQO

-- Aluminum box from Tim Sutton KI6BGE

-- Mechanical Filter from Pete N6QW

-- IF transformer from Michael AA1TJ

-- Ceramic filter from Bruce KK0S

-- 10k pot in the detector from Thomas KK6AHT

-- Inspiration and ideas from Paul VK3HN

-- Many parts from Jim... 

But you know, I find myself thinking that there are many stations I like on the 39 meter band.  I think it might be best to build a separate receiver for those frequencies.  Maybe throw in 30 meters.  Hmm, let me see what's in the junk box... 
 

Paul VK3HN's Video on Scratch-Building and SOTA

It was great to get a comment from Paul VK3HN -- this led to a re-establishment of contact.  Apparently Google knows who I have been e-mailing, so this great video appeared on my YouTube screen.  Thanks Google! 

-- Great to hear Paul's shout out to Pete Juliano N6QW, and Pete's concept of noodling. 

-- Paul's emphasis on testing each stage independently is really important. 

-- Wow, ferric chloride!  It is great to see someone doing this (instead of just sending Gerber files to China). 

-- Books.  This reminds me that I have to get Drew Diamond's books. 

-- Paul's comment on the usefulness of a general coverage receiver.  Right on target Paul.  

-- On the test gear, we can now add the TinySA Ultra.  And you don't have to win the Lotto! 

-- Finally, Paul is absolutely right on the need to constantly update and publish changes to schematics. I am guilty of not doing this. (I hang my head in shame.)   This became a problem in our simple High-School receiver project -- I would make changes to circuits and fail to communicate these changes to Dean KK4DAS.  Paul's method would have solved this problem.  

-- Thanks Paul! 

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 

Paul Taylor's Quarantine "Summit Prowler 7" and some Radio Archaeology

Paul Taylor VK3HN has really outdone himself in this video (above) and blog post. He describes coming across a somewhat mysterious homebrew SSB exciter with some cryptic markings on it. Paul eventually figures them out.  We still don't know who the builder VK3WAC was -- can anyone find him in their logbooks? 

As Paul goes through the description of the transceiver he built around the mystery exciter, he mentions a number of hombew heroes including Farhan VU2ESE, Peter DK7IH, Eamon EI9GQ (I have to get his book!), and Don W6JL.  Also,  our beloved SSDRA book plays a prominent role in the story. 

Paul's video is really beautiful -- at one point the camera pans the landscape and we see kangaroos in the field.  It is also refreshing  -- as we suffer in the heat of the northern hemisphere summer -- to see Paul and his friends out on the summits in their winter coats and hats.  

It looks to me as if Paul built this rig during the current emergency, so I will list it as a Quarantine rig.  Every dark cloud has a silver lining, and Paul's rig has added a bit of silver to the dark COVID cloud.  Thanks Paul. 

https://vk3hn.wordpress.com/2020/07/26/something-old-something-new-a-four-band-5w-50w-ssb-cw-transceiver-summit-prowler-7/

Bricoleur -- "Someone Who Fixes Stuff with Whatever he Finds Around"

A short time ago Paul VK3HN told us about the term bricolage. It seemed to capture much of the homebrew spirit.  This morning I heard Van Neistat's video-cast  (also something that came to me from Paul VK3HN) talking about the related term "bricoleur."  His  video (above) also has some great workshop ideas.  

Here is a nice Wikipedia discussion: https://en.wikipedia.org/wiki/Bricolage

Note from the Wikipedia page: 

• MacGyver is a television series in which the protagonist is the paragon of a bricoleur,^[28] creating solutions for the problem to be solved out of immediately available found objects.

HRDX Interviews Paul Taylor VK3HN

Wow, Paul Taylor, VK3HN is working on homebrew rig #11.  FB.  

This interview was quite thought-provoking. 

-- I agree with Paul about the importance of not being dogmatic about 

always staying under 5 watts.  It sounds like Paul is having fun with his 

100 watt SOTA project. 

-- It was great  to hear that Leon VK2DOB is still active in ham radio and running a QRP company in VK.  FB.  An article by Leon on CMOS mixers in the summer 1999 issue of SPRAT played a key role in my understanding how switching mixers really work.  I put Leon's diagram in my book SolderSmoke -- Global Adventures in Wireless Electronics. 

-- On blowing up the finals in simple HB gear.  The first real transmitter that I built was the VXO-controlled 6 watter from QRP Classics by the ARRL.  It had a 36 volt Zener diode across the collectors of the final.  This was to prevent the kind of final destruction Paul suffered up on that summit:  "D2 is used to clamp the collector voltage waveform to protect the output transistors if the transmitter is operated into an open circuit or high SWR antenna system."  Maybe we should revive the use of that simple SWR protection circuit, especially for SOTA rigs. 

SolderSmoke Podcast #265: AI Pete, WSPR, sBITX, San Diego, Last Ditcher, NYC, 17-12 Fix, MMM Blasphemy, 6T9er, MAILBAG

SolderSmoke Podcast #265 is ready for download. 

Video Version:  https://www.youtube.com/watch?v=-jWYe6NxnJA

Audio Version:  http://soldersmoke.com/soldersmoke265.mp3

---------------------

Travelogue:  Pete to San Diego,  Dean to NYC,  Bill stays home. 

Field Day Report!   Dean?  Pete?  I had a bad back.  Really. 

The importance of "taking a break" discussed on "Hidden Brain" podcast. 

We need new chapters for the FMLA series.  Time to add the CBLA? 

 AI Pete? http://soldersmoke.com/AIPete.mp3

Dean:  WSPR success -- Report

Back on the air with the homebrew sBITX. 

VWS WSPR TX and AMP

KK4DAS WSPR Map

Pete:   Visit to surplus store in San Diego.

The Last Ditcher CW rig.  Frank Jones would approve!  Construction technique combining wooden slats and copper clad boards is FB. 

Homebrew CW rigs -- update. 

Schematics and Co-Pilot

Shameless Commerce Division:   

Mostly DIY RF

Become a Patron through Patreon.  

Do you want an emailed heads up about blog post and pocasts?  Send your e-mail to bill.meara@gmail.com

Please comment on the Podcast (on YouTube or on the blog) and about blog posts (on the blog page). Comments let us know that we are not speaking into the Google void!  

Bill:   Fixing the receiver in my 17-12 rig.  Adding 12 db to the TIA. 

The Open Circuits book.  Eric is the Eric from CuriousMarc.  And he is a ham! 

Blasphemy?  Bill redraws schematic for Michigan Mighty Mite. 

I have 6T9 tube.  I don't really want to build a CW transmitter.  But I may have to. 

Gemini explains "Low Value Content" They see 10,000 posts and assume it is AI Slop.  

Mailbag:  

Wes:  Nice email from W7ZOI. 

Peter Marks VK3TPM fixed the index file (with help from Claude). 

Peter VK3TPM and Paul VK3HN -- Great comments on AI. 

Also Dean KK4DAS and Bob KD4EBM

VK3HN sent FB AI QSL from ZL2BNE (see mine!) 

Bruce KK0S sent two FB AI QSL cards. 

Rogier PA1ZZ -- Sends "The World of El - AI"   IDK. 

Ryan KJ7KVD building a Michigan Mighty Mite (I sent parts) 

Robert W8MOX heard my beacon from the DR to Annandale Va. 

Kirk NTOZ -- The future of ham radio and what went wrong. 

Paul KL7FLR -- The Wizard of Wasila -- Finally 3D  printed a Toroid winder

Charlie NJ7V -- Doing great work over at Red Summit RF.  

Podstatus reports that we are #2 in Ghana!  Hooray for us! 

Farhan VU2ESE -- LARCSet CW mods! 

Walter KA4KXX Homebrew POTA proposal. 

Grayson KJ7UM: Likes Helge's Norwegian paraset

Gerald VA2GJ:  Including DC RX in Canadian license study materials. 

Ron WA6YOU: Spy radios RT-6 and RR-6

Scott K6AUS: https://soldersmoke.blogspot.com/2026/06/update-how-many-drake-2-b-receivers.html We need to send him a 2B! 

Bob W8SX:  FDIM interview with Hans G0UPL.  More to follow.

VK3YE QRP by the Bay Goes VHF/UHF

Peter Parker again hosted the VK3 radio amateurs.  This time the event fell on VHF/UHF Field Day weekend.   So Peter and his friends went up in frequency and up into SPACE!  

VK3HN has a nice blog post here:

https://vk3hn.wordpress.com/2017/11/25/qrp-by-the-bay-chelsea-beach-melbourne-25-11-2017/

Be sure to read about Peter's ankle manacles -- he apparently uses them to get a good ground (sea) plane while running pedestrian mobile on the sea shore. Peter is DEDICATED! 

Adding Automatic Gain Control to the Termination Insensitive Amplifier

 

Earlier this month Paul VK3HN had a very interesting blog post about adding Automatic Gain Control to Termination Insensitive Amplifiers (TIAs).  

Termination Insensitivity is especially important in bidirectional rigs.  The shape of the crystal filter bandpass response is very dependent on the impedances presented at both ends of the filter.  In bidirectional rigs you are changing the signal path direction through the filter when you go from transmit to receive.  If the amplifiers at either end of the filter have impedances that vary depending on what is on the input or output of either stage, you will have great difficulty keeping the bandpass identical as you move from transmit to receive.  Termination Insensitive Amplifiers let you do just that -- they stay at one fixed input or output impedance (usually 50 ohms) independent of what is attached to the other end of the amplifier circuit.  This greatly simplifies impedance matching at the ends of the crystal filter. 

When I started building BITX rigs, I asked Farhan about the impedance matching problem.  He advised me to use TIAs on both ends of the filter and pointed me to a great 2009 article by Wes Hayward and Bob Kopski.  Using the information from that article, I built my DIGI-TIA transceiver, and I have used TIAs in almost all of the rigs I have built since that project.   

In his August 2021 blog post, Paul wanted to add Automatic Gain Control to the TIAs. He came up with a way to do this, but we worried that his circuit would have an impact on the impedance of the amplifiers. 

Yesterday, Wes Hayward W7ZOI posted on his web site a TIA circuit that lets us do it all:  Termination Insensitivity with Automatic Gain Control: 

http://w7zoi.net/tia+agc.pdf

I now find myself tempted to rebuild one of the TIA stages in my Mythbuster transceiver, adding the AGC circuitry from Wes's design. 

Thanks to Paul VK3HN for the blog post on this subject. And thanks to Wes Hayward for the TIA AGC design.  It is a real privilege to have direct input from Wes on questions like this. 

SolderSmoke Podcast #217 -- Beach trip, '30s station, uBITX mods, HRO RX AM, ELMAC, Teensy, MAILBAG

Bill's Bavaro DR Beach Station
uBITX in the box, HB key

SolderSmoke Podcast #217 is available: 

http://soldersmoke.com/soldersmoke217.mp3

1 February 2020

Travelogue!  Dominican Republic trip.  uBITX on the Beach.  EFHW.  LiPo Battery.  First contact of the new year. 

Bill's Bench Report

Following up on proposed uBITX mods: 

-- Put pot on sidetone line from Raduino to keep the sidetone a bit quieter. 

-- Fixed the key -- pounding brass

-- Will install 4 States QRP Active AF filter. 

-- Need to reduce power on CW to 5W

-- Stereo to mono headphone adapters. 

-- Turning off display and mic amp circuit not really worth it -- they don't pull much current. 

Pete's Bench Report: 

ELMAC Power Supply project 

1930s era transmitter? 

Teensy and SDR

PETE'S IDEA ABOUT GETTING LSB AND USB FROM BITX40

KWM-2 suggestions

Back to Bill's Bench:

Working on HRO-ish Receiver. 

Bad SBL-1  

Got idea for wider ceramic filter from Paul VK3HN

Ordered parts from Mini-kits in Australia.  They sent 6kc filters. 

Bruce KK0S sent me some 10 kc filters too. 

Installed 6 kc filter with L network matching networks.  Works great. 

Also installed Infinite Impedance Detector that Paul used. 

Needed some additional amplification ahead of the IID, so I used one stage of BITX amp. 

Works great. I can tune full 40 meter band AND 49 meter SW band.  Radio Romania, China, Radio Marti, Brazil, South Carolina. 

Beefed up the shielding to cut down on AM detection. 

MISCELLANY

-- AM and DSB in LTSpice

-- Duly Noted:  Paul  VK3HN's RIG:  "THIS MACHINE KILLS KILOWATTS"  

Kanji YC3KNJ's QRPesso Expresso Coffee in the field

-- The DANGERS of powerful magnets. 

MAILBAG: 

--KK4DAS Dean doing great things.   MMM heard at Penn State.  Where is the rest of the CBLA?

-- Thanks to Don for kind donation to the SolderSmoke cause

-- Dale BA4TB -- First SolderSmoke feedback from China.  Thanks Dale!  

--Steve Silverman:  Sideswipers and bugs were made to handle "carpal tunnel of the day"  So do I need a keyer for casual CW work? 

-- Peter VK8VWA on the limited knowledge gained from kit building. Listens to podcast while walking on the beach in Australia. 

-- Allan Hale -- Clothes Pins as Toroid holders.  Yes!  More Clothes Pins   Wild Woody Keys from Dave Ingram 

-- Pete WB9FLW  100 Watt Amp from WA2EUJ  

-- Dave Wilcox K8WPE   A medical question:  Does the Michigan Mighty Mite work differently depending on what kind of medicine was in the pill bottles used for the coil form?  Good question Doc!   Dave suggest that putting CBD on the coil or the crystals.   Anything to mellow out the ham bands... 

Pete's Plank SDR
When you know stuff, you can do stuff!

Notes from an Australian SA612 Enthusiast

One of the first articles that I put on this blog was an NA5N post about the SA-612 -- this was originally posted on December 2, 2006: https://soldersmoke.blogspot.com/2009/06/na5n-on-ne602.html  Today our friend Paul VK3HN today noted the end of production.  The SA-612 is no longer being produced, but it is not forgotten, and there are a lot of them still around.  Thanks Paul.   

One thing I would add:  It took me a while to get my head around the Gilbert Cell mixer that is the heart of the SA-612.  Here is how I came to understand it: 

https://soldersmoke.blogspot.com/2021/11/how-to-understand-ne-602-and-gilbert.html

Paul writes: 

The end of a four decade life, the NXP SA612 (in SOIC8) ceased production and the final delivery date for orders placed by the last-time-buy deadline was August 18, 2023.

The SA612 truly is a remarkable chip. It's as if The Radio Gods got together back in the early 80s and said, 'what integrated circuit can we bring into the radio world that will supercharge homebrew radio and help enthusiasts to build their own rigs?'. And after the wise council settled on a combined oscillator-mixer in a single DIP-8 package, the rest is history
.
The 602/612 launched dozens of DIY radios and even businesses, and the careers of the QRP pioneers, from Doug DeMaw to Wayne Burdick to Dave Benson. I'll bet even Wes Hayward built a few.

SA612 discussions on Groups.io lists such as Qrp-Tech ran for decades and continue to attract attention and raise new insights today.

Even Elecraft with all of their digital radio know-how and resources launched the KH1 hand-held CW rig into production with SA612s in its receiver as late as 2023.

It really is an almost ideal part for simple homebrew receivers and transmitters. A 200MHz mixer with balanced inputs and outputs, an on-chip stable LO that can be used in three ways - a crystal BFO, an LC (or varactor) VFO, or a buffer for an external oscillator or clock such as the si5351 digital PLL/multisynth. Up to 15dB conversion gain which mostly eliminates the need for IF gain. Able to be gain-controlled with a DC AGC applied to its input. And did I mention low current?

Its only weakness is in its mixer dynamic range and strong signal performance but if you put a basic BPF in front, for simple homebrew rigs at home or portable/field rigs, this hasn't really been a problem.

Of course there are other mixers that outperform the 612 but some consume much more current, and none have the built-in oscillator.

Vale the SA612. You served, and continue to support the homebrew community like no other chip. You will not be forgotten.

Fortuitously, eBay is full of $5 a piece NOS parts on tape, which pretty much guarantees they are not fake. And at this price, for all you get, they're still great value!


Paul VK3HN.

Confirmed card-carrying SA612 fan-boy.

Nick's "Shelf-17" Al Fresco Homebrew Transceiver -- Frank Jones Would Approve!

This is a really wonderful video from Nick M0NTV.  

Some reactions:

 

-- Wow, a real celebration of Al Fresco!  And of the wooden chassis -- Frank Jones would be so pleased. 

-- Nick's description of the tales of woe caused by metal boxes is right on the mark, as is his description of the benefits of leaving the circuitry visible.  He's right -- this is an art and science kind of thing. 

-- That's a shelf, but it is FAR from being a shelf of shame! 

-- I am jealous of the S-meter.  I may need to include one of those in future rigs. 

-- Great to hear the shout outs to VK3HN, ZL2CTM, and N6QW -- we are are indeed the IBEW! 

-- I think we can see the N6QW influence in Nick's decision to use a steerable filter/IF amp board.  FB. 

-- I liked hearing Helio PV8AL in Boa Vista.   When I was building simple Direct Conversion receivers for 40 meters, I knew that I had it right when I could hear Helio's roosters in the morning! 

Be sure to watch this video, and to subscribe to Nicks Channel: https://www.youtube.com/c/M0NTVHomebrewing

He has done many other videos providing more details on the various stages that make up this rig. 

I hope to work Nick on 17 HB2HB soon. 

Thanks Nick! 

SolderSmoke Podcast 262: Hybrid Wireless, 100 Watt Amplifier, Antipode VK6, Tropo DR to PR?, Mixers, MAILBAG

SolderSmoke Podcast #262 is available: 

Audio only: http://soldersmoke.com/soldersmoke262.mp3

Video:  https://www.youtube.com/watch?v=QSUyE4IaHFw&t=61s 

Intro: 

-- We are over 100 on the Direct Conversion Receiver Builds.  We talked about the receiver project at the GQRP convention.  Video on the blog.

-- G4 Geomagnetic storm November 11-12.  Messed up my computer.  Blackout in the DR?  

Pete: 

-- USMC Birthday. Having served alongside them they have my deepest respect. Veterans Day. 

-- Think about supporting those without a job this Thanksgiving. Cash to various organizations is best.

 -- 50 Hz off frequency -- What does that mean if you tune by ear and not by mouse/waterfall?

--  The Hybrid Wireless is on the air. A unique build and not often seen.

Dean:  

-- Progress on the HOMEBREW MOSFET amplifier.  Claude helped. 

Dean's 100 watt amplifier

SHAMELESS COMMERCE DIVISION:  Mostly DIY RF.   Become a SolderSmoke Patron.  Buy stuff from Amazon through the link on this blog (in the right side column). 

Bill:  

Bill's antipode from Virginia

-- VK early in the morning.  Also E51MWA and FW5K.  All homebrew SSB. My antipodes. VK6ACF Charley 11,629 miles.  Might be my most distant station worked. 

-- Preping for VHF in HI7.  Can I kerchunk Boricua repeaters with Tropo?  See: https://soldersmoke.blogspot.com/2025/09/puerto-rico-dominican-republic-tropo-on.html

-- Bill's mixer obsession. Grayson's HSD Chapter 12. The importance of knowing "the paticular go of it." EMRFD Chapter 5. 

-- The new look for the SolderSmoke blog. 

MAILBAG:  

-- Todd VE7BPO -- Doing well. 

-- Grayson KJ7UM on the loss of Jim Tonne W4ENE.  Gone, but through his writting, continuing to contribute.See: https://web.archive.org/web/20220429224036/http://tonnesoftware.com/appnotes/demodulator/EnvelopeDemodulators.pdf

-- Camden is a 23 year-old blind ham who is looking for some homebrew help. He lives in Pleasant City, Ohio, about an hour east of Columbus.  Can you help him? camden@bopp.net

-- Dale Parfitt into the QRP Hall of Fame!  The Radio Gods Approve! 

-- Paul VK3HN -- Bricolage, Cacharreo, Artilugio, and Jugaad.  SA612 going obsolete. 

-- Mike WN2A Mixers and all that. Tropo.  "Greetings from the National Radio Noisy Zone!" (NJ) 

-- Peter Marks VK3TPM -- SolderSmoke template help -- Digital HF Voice

-- Walter KA4KXX -- A great book by L.B. Cebik

-- Bob KD4EBM  -- The Bob Pease Analog Troubleshooting book. Pease quote: "My favorite programming language is solder," 

-- Cor PA3COR  Difference between mixers and adders

-- Mike WA3O  I still have his HW-7.  Amazing water-cooled amplifier.   VK3MO.  

-- Samuele IU2QBW     An Italian Homebrewer  https://soldersmoke.blogspot.com/2025/10/a-wonderful-homebrew-direct-conversion.html

-- Pil Joo VA3GPJ  Experimenting with TIA amps. 

-- Farhan VU2ESE -- USB and LSB LC filters -- Applicable for crystal filters too? 

-- Rogier PA1ZZ Thanks for the great videos! 

-- Captain Mike  KX4WC   Aeronautical Mobile --Santiago, Chile to Panama!  With Mike WA3O and Ian VK3MO:  https://soldersmoke.blogspot.com/2025/11/vk3mo-and-wa3o-brotherhood-of-ham-radio.html 

-- Dave AA7EE  A completely AI SolderSmoke? "Open the pod bay doors Hal." 

-- Pat W3RGA heard my 1 watt HI7 beacon.  Thanks Pat. 

-- Patrick Voets -- A Belgian living in the Netherlands -- supports our defiant NIMCEL position! 

-- Brian "Moses" Hall K8TIY, Father of Robert of "Crank it in Robert" fame.  Check out the video.  Young Robert appears around the 45 minute point:  https://youtu.be/Xqs2Ihucr6I?t=2730

-- Will Harris KI4POV -- an esteemed homebrewer -- asks about using 75 ohm coax. I say yes, Pete tells him how to do it right.