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Wednesday, March 11, 2020
QSO Today Interview with Dale Parfitt W4OP
Eric Guth 4Z1UG interviewed Homebrew Hero Dale Parfitt W4OP on the QSO Today podcast. The interview is really great. Listen here:
https://www.qsotoday.com/podcasts/W4OP
Wow, libration fading. Who knew?
Dale has appeared in many SolderSmoke bolg posts and podcasts. He is definitely in the Homebrew Hero category.
Check out some of those blog posts here:
https://soldersmoke.blogspot.com/search?q=Parfitt
and here:
https://soldersmoke.blogspot.com/search/label/Parfitt--%20Dale
Thanks to Eric and Dale.
Friday, July 29, 2011
Amateur radio at PAR (W4OP)
http://www.parelectronics.com/par-amateur-radio.php.
That's a nice looking 2-B Dale! Please send us the serial number! Even more impressive is Dale's award-wining homebrew solid state version of the 2-B (on the far right). Visit his web site for more info (on his site you can hover your mouse above the pieces of gear for more info).
I'm proud to say that I have a piece of gear in my shack that was built by Dale Parfitt. The story is told in SolderSmoke The Book: I'd built my own version of Doug DeMaw's Barebones Superhet and had liked it a lot. When I saw another one (this one built on a FAR circuits board) for sale on e-bay, I bought it. It stayed on the shelf for a while. Years later when I started working on it, I turned to QRP-L for help and this fellow named Dale Parfitt came to my rescue. It was only after a long series of e-mail exchanges did we realize that the receiver we were discussing had been built (and sold to me) by... Dale Parfitt.
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20
Saturday, December 12, 2009
Dale Parfitt, W4OP, Homebrew Hero
Here is further evidence that Dale and I have similar tastes in receivers: Pictured above is his solid state version of the Drake 2-B. FB! I note that the dial scales are the same as the hollow-state version.
Here is the VE3MPG interview:
http://ve3mpg.blogspot.com/2008/10/interview-with-dale-parfitt-par.html
Saturday, May 14, 2016
A Lot of Soul in the Barbados Receiver
Friday, November 18, 2022
The 2Q -- A Homebrew Solid-State Drake 2-B from 1967
This is really an amazing project. Way back in 1967 (that's 55 years ago) John Aggers W5ETT of Ponca City, Oklahoma decided to homebrew a solid state version of our beloved Drake 2-B receiver. Triple conversion. No crystal filters. Twenty two discrete transistors and no ICs. Tuned circuits at 50 kHz to provide most of the selectivity. And he did it. Just look at the picture above. It even LOOKS like a Drake 2-B.
I sent this to our friend Dale Parfitt, W4OP who more recently built a receiver like this. He too was amazed by this project.
The article by John Aggers is very clear and provides a lot of good information on how he designed and built this receiver using the technology of 1967 and junk box parts. I was struck by the lack of diode ring mixers. And I was somewhat taken aback by his use of plug-in socketed transistors. The AF amplifier is our still-familiar transformer-less push-pull complementary pair design. John did a wonderful job on the mechanical tuning and slide rule mechanism.
Three cheers for John Aggers W5ETT. This article is a reminder of the great benefit to the hobby of writing up a project and putting out there in the world. Here we are, more than half a century later, reading John's article and learning from it. FB OM.
Page 8
Monday, July 19, 2021
Michael Newton Hopkins, AB5L, Author of the FMLA series
Sunday, October 12, 2014
Pete's 17 Meter VXO Transceiver (Video)
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
Saturday, July 16, 2016
Preserving Vanguard 1
Ira Flatow of "Science Friday" was recently talking about how best to preserve important bits of the history of mankind's exploration of space. Our old friend Vanguard 1 was mentioned several times. It is now the oldest satellite still in space.
You can listen to the Science Friday show here:
http://www.sciencefriday.com/segments/protecting-the-historic-human-record-in-space/
They also have a transcript of the show on the same page.
SolderSmoke fans will remember the Vanguard adventures of Mike Rainey AA1TJ:
http://soldersmoke.blogspot.com/search?q=Vanguard
This seems to be the month for Vanguard: just a couple of weeks ago, on 40 meters I spoke to Dale Parfitt W4OP. Dale was one of the first people to pick up Mike Rainey's Vanguard replica signals (see link above).
AND...
The Vanguard reproduction project came up during Eric Guth 4Z1UG's "QSO Today" interview with Graham Firth G3MFJ of the G-QRP Club:
http://www.qsotoday.com/podcasts/g3mfj
(Graham has such a great voice. He definitely SHOULD build a phone rig!)
VIVA VANGUARD!
Wednesday, July 4, 2012
AA1TJ -- As always, in the Vanguard
----------------------------------------------------
From AA1TJ:
Wahoo...Dale, you amazing!
You are my first QSO with the Vanguard 1 reproduction satellite beacon transmitter. My circuit is a fairly close copy of the one shown on the lower left-hand corner of the 1959 CQ Magazine article (notice the output signal pick-off shown in this schematic is incorrect, or at least incomplete). My circuit uses link-coupled output impedance matching, which is similar to the only other documentation that I was able to dig up. The attached image "Early_Microlock_Bcn.jpg" was snipped from an original NASA report on the transmitter used in early airborne and sub-orbital tests leading up to the Vanguard flights.
Yes, you heard correctly. I'm using a Philco 2N504 surface-barrier transistor, but please let me back up a bit.
Roger Easton (a native Vermonter...and still resides here!) was at the helm of the communications development for the Vanguard/Minitrack project. Of the Vanguard "grapefruit" satellite beacon transmitters, he wrote in the May 2008 issue of High Frontier magazine
"We tried subminiature tube transmitters first. They worked marginally. Finally, Bell Telephone/Western Electric developed a very nice transistor for the task, and the problem was solved."
However, that leaves out a small detail. They first tried Philco surface-barrier transistors, which worked fine on the bench, however two problems were discovered. They were found to be too temperature sensitive; the RF output power from the one-stage transmitter dropped excessively at elevated temps. Secondly, there was some issue with the packaging that produced erratic operation when the transistor was rotated positionally. The Western Electric devices proved better on both counts.
The WE transistor appears to be "unobtainium" these days. That, plus the fact that my circuit won't be flying up to space anytime soon, prompted me to settle on a Philco 2N504. Although my device was manufactured in September of 1959 (Vanguard TV-4 - re-Christened "Vanguard 1" - first orbited on March 17, 1958), the 2N504 was an off-the-shelf item on the launch-date.
The only other obvious difference is the Vanguard 1 beacon circuit operated on 108MHz, whereas mine is presently working on 14.0596MHz. I recently had it running as a beacon on 10m for 48 hours but I had no luck given present band conditions.
The receiver is a simple, 0-V-0 regenerative set using a single Raytheon QF721 (fabricated in February 1953). I heard little activity on 20m when I started up my auto-keyer this morning. I had it looping 3X1 CQs whilst I worked on another project. To make matters more difficult, the exhaust fan was running in my shop and it happened to be raining heavily when you called. Worse yet, the receiver had drifted off my calling frequency by the time you called. I barely discerned a high-pitched CW "1" or "J"...which prompted me to quickly switch off the fan and re-tune. You were subsequently a solid 579.
Of course my heart jumped when I heard you calling me...how I love that feeling! And it was a fabulous QSO so far as I'm concerned. Following our contact I opened my metal index card file box and pulled out the QSL that you sent to me following our "Code Talker" QSO. To think I now have another happy memory to add to that one! Thank you once again, Dale. It figures you'd be the one to pick-off my unannounced presence on the 20m QRP calling frequency with 25mW. Well done, OM.
Also, you might enjoy this video of the actual launch, including some interesting control room audio banter. It may be found here: http://www.nrl.navy.mil/vanguard50/index.php. The way at least one of them nervously repeats, "Keep going baby!" gives some indication of the pressure these guys were under...having failed so spectacularly on two previous occasions.
All the best,
Mike, AA1TJ
Hi Michael,That was fun!I first heard you on my SG-2020 rig, but did not have a paddle handy, so I fired up the K3. I don't ever recall having QRN on 20M, but it was bad. Without it, you were 579 and even with it, 569 towards the end of the QSO.I just happened to be QRV on 060 listening when I heard your CQ's. Not bad for a 25mW signal from (I think you said) a Philco transistor.73,Dale W4OP
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
Wednesday, October 19, 2016
The Last Hallicrafters Transceiver...REBORN! TWICE!
Pete Juliano and his colleague Giovanni Manzoni led me this morning to the happy land of Hallicrafters hybrid nostalgia.
It all started with Pete's latest blog post:
http://n6qw.blogspot.com/2016/10/more-junk-box-rigs.html
I admit that I had never even heard of the Hallicrafters FPM rigs. Pete's (uh, I mean Giovanni's) video show's Pete's junk-box rebuild of the old rig. Very nice. Note the presence of the Si5351...
I needed more background info, so I turned to YouTube. This led me to more old friends: Dale Parfitt W4OP has a really nice video of his rebuild of the Halli FPM rig (see above). From his video we learn why Dr. Juliano prescribed a dose of Si5351 for the patient: Dale tells us that VFO instability was a major problem with this rig. Dale fixed his with the addition of an X-Lock board from yet another friend of SolderSmoke: Ron G4GXO of Cumbria Designs.
Dale really out-did himself by building an add-on accessory box for the FPM. Very nice. I especially liked the addition of the W3NQN passive audio filter for CW. I always have misgivings about adding audio filters to Direct Conversion receivers -- this will reduce QRM, but you are still listening to both sides of zero beat. But when you add a sharp CW audio filter to an SSB superhet you will end up with true "single signal reception." FB Dale.
Sunday, January 29, 2012
Putting 17 Meter SSB Station On the Air
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20
Saturday, June 22, 2019
SolderSmoke Podcast #212 HDR, Boatanchors, SDR, Antuinos, Spurs, QSX, Mailbag
Dale Parfitt W4OP's SBE-33 with modern digi freq counter |
http://soldersmoke.com/soldersmoke212.mp3
22 June 2019
CONGRATULATIONS TO PETE: Licensed 60 years today
Pete Juliano during Field Day, 1959 |
Hans's QSX SDR Rig at Dayton-Xenia and FDIM
W8SX FDIM interviews
Pete's SDR Projects -- Update
The Peregrino SSB transceiver in the summer SPRAT
Why no rare earth cell phone speakers in ham projects?
My HDR "waterfall" project
Farhan's Antuino
Cubesat origins
RF Lab in an box
SWR, PWR, SNA
Superhet receiver with ADE-1 at front, and log IC at the output
Adapters (SMA to BNC) help
DON'T BLOW UP THE INPUT RESISTORS (LIKE I DID!)
My dirty DIGITIA -- Denial, then acceptance
FFT
Useful programs: SPURTUNE and ELSIE
A better bandpass filter for the DIGITIA
The importance of a good test set up with Antuino
Manassas Hamfest: WA1UQO, W4WIN, AI4OT
MAILBAG:
KG7SSB
WA3EIB
VK4PG
W3BBO
Jeff Tucker -- Who owns Drake 2-B #4215?
KN4BXI
KC5RT
K3ASW
Wednesday, January 14, 2015
Broadening the Barebones Barbados Receiver
I've been working on the crystal filter of the Barbados Barebones Superhet receiver. This was designed by Doug DeMaw in 1982. This one was built by Dale Parfitt W4OP and then repeatedly modified by me. It is now on 17 meters with a crystal-switchable VXO. Earlier I had made a very crude attempt to broaden the filter from its original very narrow CW configuration. This week I did this again, but this time I actually characterized the crystals and used Wes's LDA and GPLA software (from EMRFD) to design the filter.
I played with the capacitor values and finally got the 3 kc bandwidth I wanted, but I'm having trouble getting rid of the ripple. I know this is dependent on the impedances at the two ends. The programs say I need 2000 ohms.
I'm kind of puzzled about how Doug DeMaw did this with his original design. For his crystals and his 250 Hz (!) bandwidth he said he needed 450 ohms. He used 4.7:1 turns ratio transformers at either end and said that by putting 10k resistors across these transformers he got the needed impedance. I can see how this would work looking into the gate of the 40673 IF amp, but looking back at the drain of the 40673 mixer, I'm not so sure that that would yield 10k. (See schematic below.)
But who am I to doubt Doug? So I assumed he was correct about the 10K and I re-wound the transformers with a 2:1 turns ratio, thinking that would get me closer to the needed 2k. But the ripple is still there. I guess I could use a return loss bridge at this point...
I don't know whether this is worth messing with anymore. The receiver sounds nice. The 3kHz bandwidth gives it a nice sound, and the ripple doesn't seem to be noticeable That FAR circuits board is tightly packed and difficult to work with. So, should I leave good enough alone, or should I proceed with fanatical ripple eradication. Any advice?
BTW: Why is it that receivers always seem to sound better when opened up (as above) on the workbench?
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
Saturday, December 3, 2022
SolderSmoke Podcast #242 Mars, New Hams, Direct Conversion, SDR Console, Proficio, PSSST, 8 meters, A BIG MAILBAG
SolderSmoke Podcast #242 is available
Audio podcast: http://soldersmoke.com/soldersmoke242.mp3
Video: (362) SolderSmoke Podcast #242 December 3, 2022 - YouTube
Travelogue:
Mars at opposition. Not as good as 2020 (see charts below)
SSSS Prep
Hearing aids and high frequency loss.
AirPods as hearing aids.
Out in the Shenandoah with a Baofeng.
Success among TJ High School students.
Satellite in space?
PARTSCANDY
Bill's Bench:
Direct Conversion Receiver: IT IS ALIVE! EVEN IN LTSPICE
PTO works very well.
Diode ring -- really needs a diplexer, Radio Marti.
AF amplifier simplicity.
But WHY can't you listen to DSB on a DC receiver? Now I know.
How does a diode detector work? Is the envelope real? Is it square law?
The benefits of writing... 1967 and 1966 articles on PTOs and 2Qs.
Shameless Commerce Division:
-- MOSTLY DIY RF! NEWS FROM PORTLAND! Get your free Michigan Mighty Mite.
-- YouTube Goal Reached. Thanks! Keep watching. Subscribe!
-- Keep buying from Bezos using the link on the right-hand column of the blog page.
-- Become a Patreon sponsor! Left hand column of blog page.
-- I have ads on the blog page, but I have configured to avoid troublesome ads -- dating sites, etc.
Pete's Bench
-- Stepper motor, LCD and Arduino for my little DC RX?
-- SDR Console
-- PSSST, BOMS, Schematics and spoon feeding...
-- Proficio SDR by Multus
-- 8 meters?
Mailbag
-- Alan Yates VK2ZAY now also W7ZAY PTOs, trivial motors, a broken ankle...
-- Dhaka Jack AI4SV formerly of Cyprus, Madagascar and Northern Virginia. has moved to France!
-- John WB5OAU/K5MO An old friend. FMLA as "Glowbugs Noir"
-- Dale Parfitt W4OP on the Homebrew 2Q from 1967
-- Nick M0NTV Glue Sticks, PTOs, DC receivers and AM breakthrough testing.
-- Todd K7TFC suggests “cool” names for DC RX PT Cruiser? PT109? PT73?
-- Levi replacing Selenium diodes in a Globe VFO. I am not alone!
-- Juanjo EC5ACA wants to build DC RX . FB.
-- Dave designed a discrete LM386. Picked up by Jenny at HackaDay. Can you build this?
-- George Zaff. HamRadio Workbench Spiritual Brother of SolderSmoke.
-- Alain F4IET -- Still building DC receiver. FB. Sorry I got the call wrong.
-- Drew N7DA Building Pixies with 3D forms.
-- Toni G6XMO in Sheffield getting a 3D printer business going: https://www.whizz3dparts.co.
-- Chuck KE5HPW restoring an old SW-54. Pete is skeptical.
-- Lex and Jesse like Colin's placement of WYKSYCDS sticker on his Homebrew rig.
-- Jim KI4THZ joined the Vienna Wireless Society -- FB on the faculty at GMU
-- Tony G4WIF suggested mechanical counter for DC RX PTO freq readout. I have some in the junk box.
-- Our old friend Jonathan-san in W0XO now a Patreon sponsor. Origato!
-- Thomas K4SWL sent him video of Tiny SA watching Vatican Radio sign off for the day.
-- Farhan and Chuck Penson liked blog post about Heathkit Digital Rig SS-8000 1978!
-- Ed KC8SBV working on DC receivers -- I recently used the Peppermint Bark box he sent.
-- Old friend Bob KD4EBM on the linearization of the R-390s. Hard to homebrew one of those!
-- George from VWS trying to figure out how (if?) Marconi got his coherer to work DX...
-- Steve EI5DD sends Connaught Radio news: https://www.docdroid.net/
Won’t have another Podcast until the new year so Happy Holidays to all! Merry Christmas, Happy New Year!
Thursday, December 5, 2013
W4OP -- Earth-Moon-Earth and Another Barebones Superhet
And his vintage projects here: http://www.parelectronics.com/vintage-radio-restoration.php
And here's what Dale has been doing with the Moon (that's his 15 foot dish in the picture):
for PAR Electronics, Inc.
http://www.parelectronics.com
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