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Sunday, September 14, 2025
Do I really NEED Tropo to hear the Puerto Rican FM Broadcast Station? Or are we just close enough to do this line-of-site?
Thursday, September 11, 2025
Puerto Rico -- Dominican Republic Tropo on 99.5 FM? Yes, probably
Wednesday, September 10, 2025
Puerto Rico FM Broadcast Station Heard in the Dominican Republic -- But How? WIDI 99.5 FM
WIDI 99.5 FM. Booming in during daylight here on the eastern tip of the Dominican Republic. Their antenna is about 2100 feet above average surrounding terrain. That would put the horizon at about 56 miles. But the path is about 100 miles. What do you folks think is the likely propagation mode?
https://en.wikipedia.org/wiki/WIDI
Thursday, May 8, 2025
Wow! DOVAD and Doppler at White Sands Missile Range
EI7GL has a really interesting blog post about a VHF system used at White Sands to accurately track early rocket tests: https://ei7gl.blogspot.com/2025/05/369-mhz-doppler-radar-antenna-at-white.html
He has nice picture of the antenna. The plaque has the interesting info:
The plaque on display reads as follows...
"36.9 Megahertz Helix Antenna Doppler Velocity and Position (DOVAP)
Reference Transmitter Antenna
Developed during World War II by the Germans as part of a V-2 guidance and control system, DOVAP traced the course of a rocket using the Doppler Effect caused by a target moving relative to a ground transmitter and receiving stations.
Unlike radar, Dovap did not allow scientists to "see" the rocket on a screen. Instead, it sent up radio waves, which were received and rebroadcast back to earth by the rocket. The returned waves combined with the original ground broadcast and produced a musical tone which varied with the rocket's speed - the faster the rocket, the higher the pitch.
DOVAP data was extremely accurate: it could place a rocket's position at 100 miles up within 50 feet. It could collect data at the extreme altitudes of 100 to 300 miles. Dovap's disadvantage was that it took 3 to 4 weeks to reduce the data.
The antenna is a helix because of its physical and electronic characteristics. A helix is simple to construct and operate, provides necessary signal gain and directivity, and can be operated in several modes or polarizations.
The DOVAP system provided trajectory data and ground guidance for most of the early rocket systems: Corporal, Sergeant, Honest John, Little John, Redstone, and Aerobee Upper Atmosphere programs.
This particular antenna was built in the mid-1960s near C Station. Like much of the early instrumentation used here, it was designed and built at White Sands Missile Range.
Erected by White Sands Missile Range Museum. (Marker Number 06.099.)"
Tuesday, June 18, 2024
Amazing Homebrew from Japan -- 7L4WVU's All Homebrew Station
Wednesday, May 31, 2023
Farhan VU2ESE FDIM Interview (#6) by Bob Crane W8SX: VHF Rig, sBITX, and Good News on Raspberry Pi 4
Here us Bob's interview with Farhan:
http://soldersmoke.com/VU2ESE23.mp3
Tuesday, May 30, 2023
Rick Campbell KK7B at FDIM: Interview #5 by Bob Crane W8SX
Here is the interview:
http://soldersmoke.com/KK7B23.mp3
And here is a paper Rick did on VHF. It is a bit old, but it is good.
http://www.pnwvhfs.org/conference/2009/Introduction-to-VHF-Experiments.pdf
Thanks Rick! Thanks Bob!
Saturday, May 20, 2023
Farhan Describes his New 2 Meter SSB Transceiver (Video)
Friday, August 26, 2022
PA3CRX's 6 Meter BITX in an Old CB Case
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!
Sunday, November 7, 2021
JPL, Mars Helicopter, Cube Sats, Ham Radio and more: N5BF talks to Eric Guth 4Z1UG
Here is Eric's page on this interview, with useful show notes:
https://www.qsotoday.com/podcasts/n5bf
I like to listen to Eric's shows on YouTube -- here is the YouTube recording of the N5BF interview:
https://www.youtube.com/watch?v=Fbr4jE11vfg
Here is N5BF's ham radio web site:
http://cbduncan.duncanheights.com/HamRadio/HamRadio.html
Here is the club page of the San Bernardino Microwave Society:
http://www.ham-radio.com/sbms/
Thanks to Eric and Courtney!
Tuesday, November 2, 2021
Farhan's Amazing Knack Story: From a Boyhood SW Receiver to the Design of the sBITX SDR
-- Farhan talks about his practice of taking the pictures of new rigs with the new rig sitting atop the book that was most important in its design and construction. FB.
-- I was really blown away by Farhan's presentation of how the uBITX advertisement was inspired by and in many ways based on the Heathkit ad for an HW-101. Amazing.
-- I learned a lot from Farhan's discussion of SDR theory. I pledge to spend more time with this. I really like Farhan's hybrid HDR/SDR approach.
-- But I have a question: Farhan seems to say that we'd need a big expensive GOOGL computer to do the direct sampling HF SDR. But doesn't the little RTL-SDR do just that? Without a GOOGL?
-- Great to see Wes's AFTIA being used in the sBITX.
-- Really cool that Farhan has his mind on VHF transverters when designing the sBITX. I liked use of the TCXO module to free up one of the Si5351 clock outputs. FB. And great to include an idea from Hans in this rig.
Thanks very much to Farhan (who stayed up until 3 am to do this!) and to the RSGB for hosting.
Wednesday, October 20, 2021
Super-Regeneration is Super-Strange
Sunday, October 17, 2021
2 Meter Homebrew: The Fredbox (Video)
Sunday, July 25, 2021
Possible Victory for Frank Jones and the FMLA? Could We Get the 5 Meter Band Back?
EI7GL reports some very interesting IARU activity that could possibly result in the 5 Meter band coming back to amateur radio use:
"The 60 MHz or 5 metre band has the potential to be a future allocation for the Amateur Radio service. The International Amateur Radio Union (IARU) are currently encouraging member societies to try and obtain small allocations at 40 MHz and 60 MHz."
https://ei7gl.blogspot.com/p/60-mhz.html
Regaining 5 meters was, of course, the objective of Frank Jones and the Five Meter Liberation Army. Wouldn't it be great of Michael Hopkins' fictional tale actually ended up coming true!
Thursday, July 1, 2021
Summer Reading for Homebrewers: Frank Jones and the FMLA by Michael Hopkins AB5L (SK)
I read these stories when they were first coming out and I really liked them. Here are all the FMLA episodes. Don't try to read them all in one sitting. Spread them out. Savor them. Think about the message that Frank was sending us.
All of the FMLA episodes: https://tomfhome.files.wordpress.com/2019/12/frank_and_the_fmla.pdf
--------------------------------------
Related articles, books and links:
Frank's obit: https://www.pressdemocrat.com/article/news/frank-jones/
Frank's book "5 Meter Telephony": https://w5jgv.com/downloads/5-Meter%20Radiotelephony%20by%20Frank%20Jones.pdf
Frank's 1937 Antenna Handbook: http://rfcec.com/RFCEC/Section-3%20-%20Fundamentals%20of%20RF%20Communication-Electronics/23%20-%20RADIO%20ENGINEERING%20DATA/1937%20-%20Jones%20Antenna%20Handbook%20(By%20Frank%20C.%20Jones).pdf
About the author, Michael Hopkins AB5L: https://www.rantechnology.com/index.cfm?key=view_resource&TransKey=615604E8-9DAA-40A3-9E48-4160806D893D&CategoryID=8E884CE4-9CED-4957-872B-5EBDB058D540&Small=1
Saturday, May 15, 2021
SolderSmoke Podcast #230 is available! Apr 1, Mars, Group Build, SDR, SSB, Mich Mighty Mites, Mailbag
SolderSmoke Podcast #230 is available for download
http://soldersmoke.com/soldersmoke230.mp3
Friday, February 26, 2021
EI7CLB's Ladybird Receiver (George Dobbs Design), and Voice over the Internet
Friday, January 22, 2021
Jenny List's Favo(u)rite Things
Over on Hack-A-Day Jenny List (G7CKF) has a really nice article about ham radio and homebrewing. She truly has The Knack: She got her start in radio electronics at age 9 when her parents gave her George Dobbs's Ladybird book.
https://hackaday.com/2021/01/21/a-few-of-my-favorite-things-amateur-radio/
One of her paragraphs really seemed to capture the SDR-HDR conflict that we so often joke about:
The age of the homebrew RF tinkerer may be at a close, at least in the manner in which I started it. Nobody at the cutting edge of radio is likely to be messing around with discrete transistor circuits in the 2020s, unless perhaps they are working with extremely exotic devices up in the millimetre wavelengths. It’s all software-defined radios, opaque black plastic boxes that deliver a useful radio experience on a computer but that’s it. No more homebrew, no more tinkering.
Whew, good thing I'm not on the cutting edge. It sounds kind of sad. Oh well, that leaves more discrete transistors for us to tinker with.
Jenny's Profile on Hack-A-Day:
[Jenny List]: Contributing Editor and European Correspondent
Jenny List trained as an electronic engineer but spent twenty years in the publishing industry working on everything from computer games to
dictionaries before breaking out and returning to her roots.
She grew up around her parents’ small farm and blacksmith business in rural England, so making (and breaking) things is in her blood. Countless projects have crossed her bench over the years, though these days you’ll find her working with electronics and in particular radio, textiles for clothing and costume, decrepit classic cars, and real cider from first principles.
When she’s not writing for Hackaday she works on language corpus analysis software, designs and sells amateur radio kits, sits on the board of Oxford Hackspace, and is a freelance electronic design engineer and programmer.
- Hackaday Articles
- Hackaday Profile: Jenny List
- Twitter: @Jenny_Alto
- Personal Website: Language Spy
Wednesday, October 21, 2020
Listening in on the Deep Space Network
Not long ago we took the DISH satellite antenna off our roof. For a while I resisted pleas to put the big thing on the curb for pickup. I fantasized about using it for radio astronomy. In the end, I threw it away. I do have VHF/UHF aspirations, but being able to use that dish just seemed to be something in my distant future (if ever!).
But check out what David N2QG is doing with his dishes: He is listening to very distant spacecraft normally picked up only by NASA's Deep space network. Very cool. Truly inspirational.
Here are the links:
http://www.prutchi.com/2020/10/15/recap-of-x-band-dsn-activities-and-plans-for-the-future/
http://www.prutchi.com/wp-content/uploads/2020/10/DSN_Lessons-_Learned_N2QG.pdf