https://hackaday.com/2021/12/11/has-diy-become-click-and-buy/
Podcasting since 2005! Listen to Latest SolderSmoke
Sunday, December 12, 2021
Hack-a-Day: Has DIY become Click-and-Buy?
Tuesday, November 30, 2021
Putting a Barebones Superhet on 17 Meters with an NE602 Converter (Video)
Wednesday, November 17, 2021
SolderSmoke Podcast #234: PSSST, KWM-1, VHF Woes, Mighty Midget, TinySA, 17-12 Dual-Bander Advice Needed. MAILBAG
PSSST Super Simple SSB -- 7 Transistors. Switching IF Module:
DC RX.
KWM-1 Resurrection "Shame Shelf".
How to make things work:
Diode Switching or Relays?
National Receiver.
Bill's Bench
Farhan's Talk to RSGB got me thinking of VHF 2 meter AM.
2 meter Benton Harbor lunchbox madness. SuperRegens Super Strange.
I broke my Maplin AF Sig Gen in the process. Fixed it.
Playing with MMMRX again. Put in 6 kHz ceramic filter. Sounds great SSB and AM.
Swept IF with noise, TinySA, and NanoVNA. Need better noise gen.
Mod to listen with TinySA (on blog).
Thinking of 17 meter /12 meter Dual-Bander IF around 21.4, VFO around 3.41 Mhz. Thoughts?
Sweeping double half lattice filter from Swan 240. UGLY.
MAILBAG:
--- ROOTS OF MAILBAG: Radio Moscow, Havana Cuba, HCJB, others.
-- Thomas K4SWL of the SWL Post: Could have been worse! Stairbag?
-- Drew N7DA worked Wes W7ZOI in Sweepstakes. FB.
-- Peter VK2EMU The movie Frequency and the Magic of Heathkits. Good, but not that good!
-- Thomas KK6AHT! Our old friend. Minima! Now has a young son! FB
-- Chuck WA7ZZE Saw QST profile. Sympathizes with Two-er trouble.
-- Tim M0CZP. Spell corrector. Vatican Diodes. Infallible!
-- Ramakrishnan VU3RDD Working on a NORCAL and a noise cancellation arrangement.
-- Skip NC9O said I was 40 Hz off on 17. But he had a reason to KNOW!
-- Steve K9NVD Glad he's a listener.
-- Bob KY3R Novice Nostalgia. Should he use 75 watt bulb for dummy load? Yes!
-- Todd K7TFC Video about why solder smoke goes into the face.
-- Anthony VU3JVX Homebrew Antuino. I ask for help in moving freq to 450 kHz.
-- Jack NG2E Building Pete's DC RX.
-- Scott WA9WFA HBR-13 and MMMRX.
-- Stephen 2E0FXZ also got a FT-101 VFO.
-- Bob K7ZB on the air with 56 mW and a big antenna.
-- Dean AC9JQ Retired.
-- Allan WA9IRS Right to Repair update.
-- Farhan Invited us to Lamakaan ARC, Dec 11 or 12. Will be on QO100 Satellite Live!
Happy Thanksgiving to all who celebrate this holiday!
Thursday, November 11, 2021
Scott WA9WFA's Beautiful HBR-13 Receiver (3 videos)
This is Scott WA9WFA's first homebrew construction project. He did an amazing job on a very complex project: a 13 tube superhet receiver. It features plug-in coils for multi-band coverage, dual conversion with IFs at 1600 kHz and 100 kHz, and several regenerative stages. Scott's construction is top notch. He tells us that he had been working on this receiver for several years, so long in fact that some of his friends began to wonder if it really existed. Well wonder no more. Retirement has provided Scott with the time to finish this project.
Saturday, November 6, 2021
M0NTV's "Crystal Filters for the Fearful" (video)
Wednesday, October 20, 2021
Super-Regeneration is Super-Strange
Monday, October 4, 2021
Scott WA9WFA's Mate for the Mighty Midget Receiver is WORKING! (Video)
Friday, October 1, 2021
Chuck Penson's Amazing New Book about Heathkit Amateur Products
Thursday, September 16, 2021
The HBR-13C Receiver and the Poetic License of Homebrewers
I've been hanging out on 17 meters with my homebrew VXO-controlled BITX transceiver. The antenna is my 75 meter doublet fed with window line through a homebrew tuner made from dead ( I swear) DX-40s and DX-60s. I can tune it up just fine on 17 meters, but I realize I probably have lots of nulls and lobes in the radiation pattern. Apparently one of the lobes is over my old stomping grounds in Panama. Almost everyday I talk to either HP9SAM or HP3SS.
Robby, HP3SS, is using SDR gear now, but he was a real homebrewer back in the day. Years ago he built an HBR-13C receiver. That's quite an achievement.
Robby -- formerly VY2SS -- told me that he sold his HBR-13C to none other than Joe Walsh, the rockstar from The Eagles. FB.
As I was talking to Robby yesterday, I came across this wonderful web page about the receiver:
https://sparcradio.ca/wp-content/uploads/2015/12/Restoring-a-HBR-13-Amateur-Receiver.pdf
Robby told me that his receiver looked almost exactly like the one on the SPARC site, but he didn't recognize the small box with what looked like a speaker on the chassis. I told him that my guess was that this was a crystal calibrator in an oven.
I also told Robby that I feel an affinity with the HBR project, not just because I like homebrew superhets, but also because my call in the UK was M0HBR.
There are some great quotes in the SPARC pdf:
The SPARC page led me to the amazing website of Kees K5BCQ:
https://www.qsl.net/k5bcq/HBR/hbr.html
Here is Kees's QRZ page:
Wednesday, August 11, 2021
More Info on Tom's Amazing Junkbox 20 meter Receiver (using FPGAs)
Tom also sent me Firmware sourcecode that may be reusable for STM8 users, and the FPGA design file (for Quartus users). If anyone has a GitHub or similar site that can host these files, please let me know and we will send them to you.
Friday, July 30, 2021
Video: Rob Sherwood NC0B on Transceiver (and Especially Transmitter) Performance
Rob Sherwood NC0B is one of the real authorities on receiver performance. Many of us have relied on his ratings of commercial receivers for many years. His recent presentation to the Madison DX Club has a lot of really interesting information. There is also, I think, some stuff that homebrewers will find distressing.
Just some things that I noticed:
-- Rob mentioned a move back to 9 MHz IF filters and a move away from dual-conversion rigs with a high IF. He also mentioned the combination of a 9 MHz IF and a 5 MHz VFO as a way of easily getting on both 75 and 20 meters.
-- Rob discussed phase noise from synthesizers, a topic we discussed at length (some would say ad nauseum!) a year or so ago.
-- Rob really praised the "Pure Signal" system of one of the SDR manufacturers. He showed the completely rectangular waterfall display of a Pure Signal transmitter. I'm afraid that simple crystal rigs might never live up to this standard. An embrace of this high standard could discourage the construction of simpler, HDR rigs. We should not let the perfect be the enemy of the good!
-- We often hear SSB ops complaining that some other SSB op is "splattering all over the band." It often turns out that what is really happening is that a clean SSB signal is just overloading the receiver of an operator who does not know how to turn off his pre-amp or turn on an attenuator. Rob shows us how to really know if the problem is in fact at the other end: He looks at key clicks from two different CW signals on 160 meters. Both are at roughly the same level in his receiver But one is clicking all over the place while the other is not. With this kind of comparative info, we can be sure that the problem is the transmitting station's fault.
-- In discussing when to turn on the pre-amp (or the attenuator) Rob revives the old practice of just listening to the band noise. If you can hear the band noise when you switch from dummy load to receive antenna, you have enough RF gain. Adding more will only make things worse.
-- There was an interesting question about how to evaluate the performance of receivers when there are many signals inside the receiver's passband. This is the case with FT-8. Rob said this situation needs more research.
I don't mean to be critical here -- Rob is the guy who evaluated commercial rigs. And he is a contester. So his presentation is, of necessity, going to have a very "appliance operator" orientation. There seems to be an assumption that the only "rigs" that modern hams can use are commercial products. At one point Rob admits that most hams just can't repair these rigs. There is much for homebrewers to learn from experts like Rob, but presentations like this also remind us of what a tiny minority we really are, and how most hams have moved completely away from the old ham tradition of building our own rigs.
Thanks to Rob Sherwood and the Madison DX Club. And thanks to EI7GL for alerting us to this important presentation.
Monday, July 19, 2021
Michael Newton Hopkins, AB5L, Author of the FMLA series
Thursday, July 15, 2021
Wednesday, July 14, 2021
Mythbuster Video #4 -- First Signals, 75 meter Bandpass Filter, Yaesu VFO output
Sunday, July 11, 2021
A Video Series on the Mythbuster 75/20 Rig -- Video #1
Thursday, June 10, 2021
Tom's Receiver -- A 20 Meter Superhet Built From the Junkbox
Wow, this is really an amazing project. It is so good that I'd like to believe that it is really "all our fault," but the credit obviously goes to Tom, the very intrepid builder. In a more just world, Tom would be given a ham radio license solely on the basis of this project. Great work Tom. We look forward to more Solder Defined Radios from your workbench.
I stumbled across your podcast a few years ago. I had no interest in
amateur radio, I was just looking for an electronics podcast that
actually discussed electronics (naming no names here, obviously).
Well, the inevitable happened, and some of your enthusiasm rubbed off
on me. I now find myself humbly enclosing a photograph of my first
homebrew receiver for 20m.
The project was one of those "spontaneous construction" affairs,
triggered mainly by breaking up an old satellite receiver (I've
honestly no idea what it was for) which yielded up several SBL1s and a
10.7MHz crystal filter - these form the key elements of the new
receiver. It's a full SDR (solder defined radio) of a conventional
single-conversion superhet arrangement. The chief abnormality is that,
because the IF filter is as wide as the proverbial barn door, I only
use "one edge" - the other half of the passband being provided after
conversion to baseband. Of course, that only works if there are no
massively strong stations in the 6kHz above where you're listening,
but it seems to be ok most of the time. It does give me the advantage
of being able to adjust the lowpass point of the AF signal by
adjusting the BFO, which is nice.
You'll notice there's a lot of "digital nonsense" in the picture, for
what's supposed to be an analogue radio. This "supervises" the two
VCOs: There is an FPGA which implements a pair of frequency meters and
an STM8 microcontroller which is in charge of adjusting the control
voltages to keep the VCOs where they should be. It's all slightly
roundabout because I wasn't clever enough to design a PLL which would
give the required resolution (and I wanted to do something "more RF"
than throw down a DDS chip).
This gives me stability as well as fancy bells and whistles, like
numeric readout, tuning info via RS232, automatic scanning and
frequency presets. I've used a (cheap) industrial/automation style
encoder for the tuning control, which gives a lovely analogue-like
action.
Despite my best efforts (and a lot of ferrite in strategic places) I
wasn't able to keep all the digital spurs out of the receiver. So I
devised a dirty hack by way of a button which will shift the MCU an
DAC clocks to a different frequency. I can't remove the spurs, but now
I can hide them!
So far I've played with a "long" wire and a little shielded loop for
antennas - I'm in a first floor flat with a lot of noise locally, and
my plan is to get a loop up in the loft space (so the next project
might be a rotator!). I fancy maybe seeing if I've space for an
inverted V, too.
You'll notice that I've not attempted a transmitter. That, of course,
is because I'm not yet a licenced ham! However, I'm intending to put
that right sometime later in the year. Then - who knows - I might make
a contact!
Thanks for reading (although really it's the least you could do given
that this *is* all your fault) and I hope you've enjoyed hearing about
all the trouble your little podcast has got me into.
Keep up the good work gentlemen,
73 from South-West England.
Tom.
PS. I also have a copy of Bill's book, which I've very much enjoyed.
Wednesday, January 20, 2021
Guilt Trip: Video on the Heath QF-1 Q Multiplier
Sunday, January 3, 2021
An End to the HDR - SDR Conflict? Kevin AA7YQ Combines the Best of Both Worlds
We've had some pretty amazing contact with Kevin AA7YQ over the years. Kevin and I originally bonded due to our common experience with parachutes (he was smoke-jumper, I jumped while in the army). Kevin once used a parachute to insulate a QRSS beacon. And one day, while thinking about SolderSmoke during a drive through Montana, Kevin turned on his rig only to hear... ME! He caught one of my infrequent CW contacts. TRGHS.
Now we hear that OM Kevin may be poised to end the HDR-SDR civil war that has for so long been dividing our great podcast. Can Kevin's new rig heal our wounds and allow us to enjoy the beauty of SDR waterfalls while not forsaking the joy of hardware defined rigs? Kevin will soon launch a blog describing his effort at rig-building. See below for a preview. Stay tuned.
Kevin wrote:
I am currently working on a new rig design. It is a hybrid HDR(Hardware defined)/SDR radio that incorporates some classic superhet design along with some of the more useful features of SDR. I have found that pure SDR is really not that enjoyable for me. I love using GNU radio to mock up and test design concepts, but SDR basically dilutes the “magic” of radio to nothing more than software and touchscreens, stuff we use every day all day. Its not the Ham Radio I grew up with as a kid and was fascinated by. On the other hand, I have always fought temperature drift, large variable capacitors minimal tuning range, and associated with classic VFO and VXO designs. In fact, in 1997, for my senior capstone design in EE at Montana State University, I designed a 20m superhet that used a DDS LO. At the time DDS was cutting edge technology I used an AD7008JP50. I had to beg and plead with ADI to get a couple samples for my design, since they exceeded my self-funded college student project budget. 😊 But that’s another story. SDR has made me grow extremely fond of the waterfall display. I love having the visual “situational awareness” of what is going on in a moderate bandwidth outside of the spot I am tuned to. I also am a big fan of digital filtering and modification-ability that comes with boot-loadable microcontroller designs. So this design includes most of the real highlights of SDR but does not take the fun out of designing, building, and operating a HDR.
Anyhow, this design is a big goal of mine to complete and build in 2021. I am not retired yet so I still have to balance, work, family, and tinkering time, but I am very excited about this project. I have “noodled” this design to the point of what I have achieved full-on “analysis paralysis”. That is, I keep designing and redesigning, optimizing, and figuring to the point where after months of thought, I have nothing to show for it 😊. So my New Years goal for 2021 is to make “good enough” rather than “perfect” design decisions and move forward. I will keep you posted on the design and possibly start a blog so I can get some peer review input from the greater RF Design/Homebrew community on my project. I’ll keep you informed on my progress.
Sunday, November 22, 2020
The Wizard of Horseshoe Bend: VK2FC's Wonderful Projects
http://www.vk2fc.com/progressive_receiver.php
Glen's site has many other projects. Check them out:
http://www.vk2fc.com/index.php
And here he is, the Wizard of Horseshoe Bend:
Monday, November 9, 2020
Improving the Product Detector in the Lafayette HA-600A
Steve N8NM built the HA-600A product detector both in LTSpice and in the real world. It worked fine in both versions. Steve even put the product detector into his S-38 receiver -- he reported it worked well there.
I too built the thing in LTSpice. Then I went and rebuilt the circuit on a piece of PC board. I connected the new circuit to the HA-600A, using my external FeelTech sig generator as the BFO. IT STILL SOUNDED BAD ON SSB.
At this point I started Googling through the literature. I found a promising article by Robert Sherwood in December 1977 issue of Ham Radio magazine entitled "Present Day Receivers -- Problems and Cures." Sherwood wrote:
"Another area that could use additional work is the product detector. As the name implies, its output should be the product of the two input signals. If BFO injection is removed, output should go to zero. If this is not the case, as in the Heath HW series, envelope detection is also occurring, which causes audio distortion."
I checked my circuit. When I removed the BFO signal from the product detector, envelope detection continued. In fact, with the receiver in SSB mode, and with the BFO disconnected, I could listen to the music of WRMI shortwave. It seemed that Sherwood was explaining well the problem I was having: Simultaneous envelope and product detection was making SSB sound very bad in my receiver. What I was hearing just seemed to SOUND like what you'd get with a mixture of product and envelope detection: "scratchy" sounding SSB. This also seemed to explain why SSB would sound fine when using the diode detector with loosely coupled BFO energy -- in that case it would be envelope detection only, with no ugly mixture of both kinds of detection.
Finally, I needed to find a way to use the BFO in the HA-600A with the new product detector. Obviously I needed more BFO signal -- I needed about 7 dbm, enough to turn on the diodes. I converted the outboard product detector board into a simple amplifier and put it between the HA-600A BFO and the BFO input port of the new product detector. This works fine.
A few issues remain:
1) The output from the HA-600A BFO through the above BFO amp (and across the 50 ohm resistor) is NOT a pretty 455 kc sine wave. But the peaks of the distorted wave appear to be enough to turn on the diodes, and when I look at the voltages across each diode (on my two channel 'scope) I see mirror images -- one is on when the other is off. Is this good enough?
2) Moving the BFO input from L1 to the junction of the two 50 ohm resistors (that is actually a 100 ohm pot) has big implications for how this mixer works. With the BFO energy going through the toroid, BOTH diodes are being alternately turned on and turned off. But both are on, and then BOTH are off. With the BFO energy going in through the other side, one diode turns on when the other is off. I think the mixing result is the same, with AF coming out of the output port, but the way the mixer works in this configuration is very different. Does this sound right?