This (above) is a general Shortwave Superhet receiver I built over the winter. I chose to go modular so I could interchange some of the modules and make easy repairs and changes to the circuits. I used discreet components and only 2 integrated circuits. I built a Colpitt's buffered oscillator which is remarkably stable, a Gilbert Cell Double Balanced Mixer, a high pass filter to filter out local AM broadcast station. The IF chain uses an old classic collins 455 khz mechanical filter amplified by a J310 feeding into an MC1350P IC... It's using 2 germanium diodes as a detector feeding into an LM386 output amp. It's very, very selective and sensitive. I added a 455 khz BFO (lower right in pic) the other day to tune in SSB and CW. This has been a fun experiment.
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Saturday, May 2, 2020
Friday, May 1, 2020
10 Meter Quarantine QSOs near Boston -- KC1FSZ's Peppermint 10
Hi Guys:
I hope all is well. Thanks for the more frequent episodes!
I’ve not submitted anything lately but I’m still doing a lot of building. Over the last few weeks I’ve been working to get myself on 10 meters. There is some good local activity up here in the Boston suburbs on 10. The result of this effort is the next in the Peppermint Line of high-performance radio products for the discerning operator: The Peppermint 10. This rig uses digital VFOs and puts out about 12 watts on a good day. It works in conjunction with a direct-conversion receiver that has been modified for 10 meters. The details are described in the write-up (see link):
73s,
Bruce KC1FSZ
Labels:
10 meters,
direct conversion
Thursday, April 30, 2020
Shortwave Dials -- Exotic Locations -- Hong Kong! Berlin! Springfield? Schenectady?
Click on the picture for a closer look.
No offense to the birthplace of Homer Simpson, but Springfield? And Schenectady? This dial glass is all that remains of a shortwave receiver used by my wife's grandfather in the Dominican Republic.
Many years ago the Boatanchor enthusiasts had a very informal "dial lights" competition. Which receiver cast the best glow from its dial lights. (I think my HQ-100 was the best.)
The dials of many old shortwave receivers have recently started to show up on the Shortwave Listening group on Facebook. Some have some very exotic foreign locations. Perhaps we should launch a similar competition: Which SW receiver dial has the most exotic foreign locations?
Wednesday, April 29, 2020
Applied Science -- Electrical Impedance Tutorials
Part 1 appears above, Part 2 is below.
Ben Krasnow has a KNACK for explaining technical things. I liked his videos on impedance. At the end of the second video, he said he'd do a third one that would focus on impedance in coaxial cables. But I couldn't find it on his channel. I hope it was made -- this is very interesting and useful.
Ben's YouTube channel is here: https://www.youtube.com/user/bkraz333
Labels:
mathematics,
Physics
Monday, April 27, 2020
Listen to Homebrew-to-Homebrew Quarantine Contact with Glenn KU4NO on his 37 year-old Homebrew SSB Transceiver
This was really amazing. I had been feeling guilty about not getting on the air much during quarantine. I mean, we have these airwaves and we have the gear, right? Shouldn't we be more social, more friendly and get on the air more? I tried yesterday with marginal results (conditions were poor). I called CQ on 40 SSB this morning -- nil, except for one grumpy guy who said I was splattering on his morning coffee clatch. Then I heard KU4NO calling CQ. I did not recognize the call. But when I told him I was on a homebrew transceiver, he matter-of-factly sad that he too was on a homebrew rig. When he started to describe it (see below), it all came back me. His is one of the most soulful of homebrew SSB rigs. And I realized that it may also be THE OLDEST HOMEBREW SSB RIG STILL IN USE IN THE WORLD. (If anyone knows of a homebrew SSB transceiver older than 37 years and still on the air, please let me know.) This was exactly the kind of contact that I needed. TRGHS.
Glenn put out a lot of homebrew wisdom. He said a lot of inspiring things. (He did also at one point talked about wanting to shoot his plasma TV, but that's understandable.) So I recorded most of our contact. (I have his permission to put it on the web).
You can listen to our contact via the YouTube video above.
For my report on an earlier contact with Glenn click here:
https://soldersmoke.blogspot.com/2018/07/a-rig-with-maximum-soul-5-band.html
So, it is worth it to get on the air. They are rare, but people like Glenn are out there, running very interesting rigs. And when you find them, you feel like you've hit the jackpot.
Thanks Glenn!
Labels:
HB2HB,
Knack Stories,
SSB
Saturday, April 25, 2020
SolderSmoke Podcast #221 is available -- Quarantine Rigs, Phasing, SWL, Parts Suppliers, Mailbag
Q-31. "Roll-bar" on cap. Note RGS316 coax between stages. Country markings on tuning dial |
25 April 2020
http://soldersmoke.com/soldersmoke221.mp3
Obviously no travelogue. QUARANTINE. SITS.
Good news: Lawyers
at Dewey Cheatham and Howe report that SolderSmoke will NOT be taken off the net
for brazen promotion of the S-38E receiver.
Also some good news on the FT8 vs. FT-FAKE issue. That report itself was fake.
PETE’S PROJECTS:
Phasing SSB
And what’s this about a tube CW rig?
Dean KK4DAS builds Pete’s Simple SSB rig. Quarantine Rig: The Furlough 40. See: https://kk4das.blogspot.com/
SHAMELESS COMMERCE
DIVISION: NEW AMAZON LINK IN THE
UPPER RIGHT SIDE OF SOLDERSMOKE BLOG. .
BILL’S BENCH:
QUARANTINE PROJECT:
Q-31 AM SW Receiver. April 4 through
April 19. 15 days of fun. Learned a lot.
Need to pay attention to total gain. Need to measure. Not always easy. My resistor-based technique.
AM detection can be more difficult than SSB/CW detection. Germanium diodes make a big difference.
But…I don’t have to build a BFO, because these signals bring
their own beat frequency.
455 CAN BE PROBLEMATIC AS AN IF – image response, making
impedance matching transformers tough at those low frequencies. But WIDE filters available.
LM386 AF chip make a LOT of audio. Hard to reproduce these great results.
Great stuff you can listen to on 31 meters (9.4 –10 MHz):
n
DX WaveScan
n
WRMI Rock and roll
n
VORW music show
n
Radio Nacional De Espana (Madrid)
n
China Radio International soap operas and Confucius philosophy
lessons.
n
China Radio International Chinese Lessons.
n
Radio Greece
n
Radio Republica (France)
n
Radio Havana Cuba
n
Radio Saudi Arabia
n
WBCQ – They advised listeners to fix up an S-38
during quarantine! !!!!!!!
n
WWV
SHOPPING BAG -- THINGS TO GET:
-- Great source for hardware (screws, nuts, bolts and more): McMaster-Carr https://www.mcmaster.com/
-- Thermax RGS316 coax.
Great stuff. Thanks Jim In some ways better than Belden 1671A https://soldersmoke.blogspot.com/2012/03/murphys-whiskers-shaved-with-belden.html
-- Copper Clad board: Pete’s boards use CEM 1. CEM 1 is low-cost, flame-retardant,
cellulose-paper-based laminate with only one layer of woven glass fabric.
-- BEST TEST LEADS: https://www.ebay.com/itm/BEST-TEST-LEADS-PERIOD-Hand-Soldered-MINI-CLIP-Version-32-16AWG-Ultra-Flexible/233519356767?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
NEED/WANT:
-- Thermaleze magnet wire.
First encountered in QRP GUYS EFHW tuner kit. Very FB
Resistor kits
NP0 cap kit
Replacement Iron for XTRonic 4000 Iron.
RIGOL PROBES Why do we burn through so many of these?
MAILBAG:
-- Eric 4Z1UG Episode 300 Special
-- Farhan working on ventilators. Special thanks to Dr. Gordon Gibby KX4Z.
-- Jonathan-San working out of new shed in Seattle
-- Grayson reminds us of the Fran Lab: https://www.youtube.com/channel/UCMLgHbpJ8qYqj3CkdbvC0Ww
-- WRMI likes SolderSmoke
-- Peter VK2EMU continues to build his amplifier. But it is NOT for 50 MHz. It does have 6 different meters on the front
panel. But it is not a 6 meter rig!
-- Rich K7SZ – “now look what you’ve done” Fixing up an S-38
-- Rich WD3C Provided
some great SWL links:
https://www.short-wave.info/ if you move the green dot to your location
it will predict what the signal strength would be at your location and will
also allow you to search by station, language, frequency, etc.
Thomas
Whitherspoon, https://swling.com/blog/ Another, https://shortwaveschedule.com/ and of coarse https://www.hfunderground.com/board/index.php all the pirate broadcasters show up
here.
-- Paul KL7FLR amazing
S-38E diagnosis from afar. Paul's toroid tool (more to follow on this).
Pete's Quarantine 6V6 Rig |
Friday, April 24, 2020
Quarantine Search for Zombie Satellite in Geo-Synchronous Orbit
Nice two minute audio report:
https://www.npr.org/2020/04/24/843493304/long-lost-u-s-military-satellite-found-by-amateur-radio-operator
Scott Tilley is VE7TIL
https://www.npr.org/2020/04/24/843493304/long-lost-u-s-military-satellite-found-by-amateur-radio-operator
Scott Tilley is VE7TIL
The NanoVNA
Jenny List has a good article on Hack-A-Day about the NanoVNA.
The ability to measure impedance would be very useful.
Labels:
test gear
Thursday, April 23, 2020
WA7SKT's Al Fresco DSB Rigs
Loren WA7SKT wrote:
Got the balanced modulator and first RF power amp board mounted today for my 20 meter DSB transmitter (above). Still have to build carrier oscillator and final RF power amp boards yet. Coax with BNC connector is carrier osc input to bal mod. As is puts out 8.5mw into 50 ohm load.
Audio in through 2N3904 emitter follower to SBL-1 balanced modulator. Rf out to a 2N4401 Class A RF amp. Will have a final RF power amp stage and to the lowpass filter. Targetting 250mw output max for WSPR. Will add the 2N3904 Colpitts oscillator with tuned collector for carrier oscillator. Power supply will be 9 volts and 12 volts.
This is part of my fun in eventually building a 20 meter SSB transceiver. I am not interested in anything multi-band. This is my second DSB transmitter. First is larger and uses Si5351 for carrier oscillator.
I also plan on building a WSPR transmitter using an Arduino and Si5351 synthesizer so I dont need my PC. There is a frequency shift program for Arduino to control Si5351. I use Si5351 now for VFO’s. My first WSPR transmitter uses one just for carrier oscillator.
Loren's First DSB Rig |
I like Loren's self description on Twitter:
Wednesday, April 22, 2020
Jonathan-san (Our Man in Japan) Now Melting Solder in Seattle
Got a nice note from Jonathan W0XO. He and the family have relocated to the Seattle area. Here we see Jonathan at work in his new shed/shack. It looks great.
Long-time SolderSmoke fans will remember Jonathan from his previous life in Asia. See:
Tuesday, April 21, 2020
Please Listen: Something Wrong with Spanish National Radio Signal?
I've been getting back into shortwave listening. One of my favorite stations is Radio Nacional de Espana (Spanish National Radio) from Madrid. It is very strong here on 9690 kHz starting around 1645 Eastern Time, 2145 UTC.
If you can, please listen to this station and let me know if you hear any technical problems with the signal. Please let me know what you hear. Does the signal sound OK. Any problems?
Labels:
Short Wave Listening,
Spain
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