Yet Another Aeronautical Mobile Contact with KX4WC/AM, with VK3MO in the Group

WA3O sent me an e-mail alerting me to the fact that Mike KX4WC/Aeronautical Mobile would be flying up from Santiago, Chile to Panama City this morning. So I fired up the 20 meter rig and hoped for the best.

Not only was I able to talk to Mike, I was also able to work WA3O, VY2WW, and VK3MO in Melbourne. It was a very FB morning. VK3MO was really booming in. I have worked Ian before -- his 5 over 5 over 5 over 5 array on 20 meters really helps. https://www.qrz.com/db/VK3MO

I was not hearing Mike KX4WC very well until the sun came up over our north-south path. You can see this in the picture below. Thanks to all for this very cool contact.

Ian VK3MO's 20 meter array

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?

 

WIDI 99.5 FM from western Puerto Rico continues to put a full quieting signal into the eastern Dominican Republic.   The station is so regularly strong that this made me wonder if I am really using tropospheric ducting to hear it.  If I was using tropo ducting, I think there should be some variation in signal strength over the course of 24 hours right?  But it is always strong.  Why?  

I checked the distance:  97 miles.   With its antenna at 2800 feet, its visual horizon will be 64.8 miles away.  I am about 98 feet above the ocean.  This means my horizon is 12.22 miles away.  There appears to be a gap, right?  I mean 64.8 + 12.22 = 77.02 miles.   So it looks like there is a gap of about 20 miles.  

But wait!  Mike WN2A reminded me that there is a difference between radio line of sight and visual line of sight.   Radio line of sight = 4/3 of visual line of sight. 

AI explains where the 4/3 factor comes from: 

The radio horizon appears longer than the visual horizon by a factor of about 4/3 due to atmospheric refraction, which bends radio waves slightly downward. To simplify calculations, this effect is modeled by treating radio waves as if they travel in a straight line over a larger, "effective" Earth with a radius 4/3 times the actual radius. This increased effective radius allows radio waves to "see" further over the Earth's curvature, extending the line-of-sight range compared to what is seen by the human eye, which is not affected by atmospheric bending to the same degree. 

So that puts WIDI's radio horizon at 86.4 miles.  My radio horizon is 16.16 miles.   86.4 + 16.16 =  102.56 miles No gap.  We should be able to hear WIDI, even without tropospheric ducting.   

Puerto Rico -- Dominican Republic Tropo on 99.5 FM? Yes, probably

 

Our friend Todd K7TFC in Portland found this in the 1950 ARRL Handbook at an, uh, opportune moment.  TRGHS.  This seems to describe what a I am hearing, especially that "airmass boundary" in the lower left of the diagram above.  

I'm not a VHF guy, and I am a bit surprised at the persistence of this propagation path.  It is 4:30 am here and the adult contemporary rock from Puerto Rico (Kokomo by the Beach Boys!) is full quieting here in the Dominican Republic.  And it is of the same strength during daylight hours. I don't remember this from the winter months, but I may have just missed it. 

Here is what AI (Gemini) says about this: 

https://share.google/aimode/M1HvC7Y893eE5gAcn\

One other factor to consider:   The island of Mona is about halfway across the path.  There are few people there, and there is almost certainly not a repeater of any kind.  But there may be a metal tower or two... 

Gianfranco IU1DZZ and Mike WN2A  both support the tropo hypothesis.  Mike mentions the Hepburn Index.  I will have to read up on that.  Hamilton is also looking at this propagation path.  Thanks guys.  

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

One (of several) SolderSmoke Blog Backups: This one in .pdf form

The SolderSmoke Daily News blog now has more than 4,000 posts, and some 10,000 comments.  This is both good news and bad news.  The good news is that there is on this blog site a vast repository of useful information.  The bad news is that I sometimes fear that all this info might be lost if Google someday decides that its blog service should disappear.  It could happen, and that is kind of scary, so I have been looking for backups, for ways to safeguard this information. 

Several members of the SolderSmoke community have been helping me create WordPress sites that backup the blog. More info will be coming soon.  The Internet Archive and the WayBack machine have also been of great help. 

While here in the Dominican Republic, I have been working on a kind-of compilation of blog articles, with a bit of an intro.  I think readers of the blog and listeners of the podcast might find this entertaining. 

So here it is.  Please download it to your computer.  That will increase the survivability of the blog.  I will probably do a few updates to the .pdf file: 

http://soldersmoke.com/SolderSmoke Blog Book Compilation.pdf

A Second Aeronautical Mobile Contact with Mike KX4WC/Aeronautical Mobile

August 19, 2025 20 meter SSB in the afternoon. Mike KX4WC/Aeronautical Mobile was enroute to San Juan from Miami, flying through the edges of Hurricane Erin. Also in the QSO was John VY2WW and Mike WA3O. WA3O is a long-time listener to SolderSmoke. He has a water-cooled amplifier and he sent me his Heathkit HW-7 (which I still have).

Mike and I could hear each other through most of his flight.  We were both especially strong when he reached his closest point to my location.  At this point he was about 50 miles over my north-east horizon: 

Amazingly, this was NOT my first contact from the DR with KX4WC/AM.  In January 2020 (just beore the pandemic) I was in Samana, and, early one morning Mike flew over the Dominican Republic.  Here is an e-mail that I sent yesterday to all three guys who were in this very memorable QSO: 

I really liked today's QSO.  Mike called me from around 50 miles out.  We were both very strong. 

The first link describes in detail my 2020 QSO with Mike from Samana, DR.   The second describes my Samana station.  

https://soldersmoke.blogspot.com/2020/01/aeronautical-mobile-contact-from.html

and

https://soldersmoke.blogspot.com/2020/01/contacts-from-dominican-republic.html

Here is my current station:

https://www.qrz.com/db/HI7/N2CQR

And wow!  WA3O  Who could forget that water-cooled amplifier!?  And I still have his HW-7   Thanks Mike. 

SolderSmoke Podcast 261: Travel, AI-Apocalypse, ARRL Award, Amplifiers (with Claude) , Transcoms, Smoke released in DR, QRP, CW, MAILBAG

SolderSmoke Podcast #261 is available for download: 

Audio:  http://soldersmoke.com/soldersmoke261.mp3

Video:  https://www.youtube.com/watch?v=1rzw8lxBzRo

Alaska, Colorado, Dominican Republic

Opening:   Travel notes:    Pete to Denver.  Dean to Alaska.  Bill in the Dominican Republic. 

The future of the podcast.  We will embrace our NIMCEL status and fight on in spite of the AI Apocalypse.   Thanks to Peter VK3TPM, Hamilton KD0FNR, Sam AI7PR, Todd K7TFC  and the WayBackMachine for providing backup and transfer options for the blog. Google could end Blogspot at any time.    

Dean and Bill win the 2025 ARRL Technical Service Award.  Thanks to Bruce KC1FSZ for the nomination. And thanks to Bill Morine N2COP for letting us know.  91 receivers completed so far!  

SolderSmoke East was pleased to host Phil W1PJE, a distinguished MIT radio astronomer AND member of the SolderSmoke Direct Conversion Receiver Hall of Fame.   

Dean:   Amplifier design,  woes, triumphs, tribal knowledge.  And help from Claude. 

KK4DAS 100W MOSFET AMP

Pete:  Project X  -- The Transcom SBT-3,  Crossroads and Decisions. 

Transcom SBT-3

SHAMELESS COMMERCE DIVISION:   FIGHT THE AI-APOCALYPSE -- BECOME A PATREON SPONSOR.

GET BEZOS TO SEND US BEZOS BUCKS!  Use the Amazon link on the upper right.   

BUY PARTS AND STUFF FROM MOSTLY DIY RF. 

Bill: 

-- Smoke released in TWO RD06 finals.  Scrounged IRF-510s to the rescue.   

-- Working VK6 on 20 SSB.  

-- My old HW-101 -- inspired by Pete and by Will N5OLA.   

-- High frequency hearing loss and direct conversion receivers. 

-- Eleven contacts on 40 with the DC RX and a Tuna Tin 2. Mike Bryce WB8VGE came back to my CQ! First ever QSO with SolderSmoke DC receivers on both sides:  K1OA-N2CQR.  

-- Do real hams use ALC? Do we really NEED ALC? 

Mailbag: 

Who is the Project 326 Guy?  A British engineer resident in China for last 20 years. 

Steve EI5DD  Ham Radio Ireland magazine.  Hey -- Why no Irish DC RX builders? 

Paul K9ARF -- Thanks for the very kind e-mail about SolderSmoke. 

Rogier PA1ZZ -- Many nice videos and suggestions on blog backup. 

Grayson KJ7UM on the EF-50 valve (thermatron!) 

Bruce KC1FSZ  Four DC RX builders at the Wellesley Mass radio club. 

Chris KD4PBJ -- Long trip to pick up two directional beacons possibly for 630m or 2200m bands! 

Alan W2AEW did a Minimum Discernible Signal test on the DC RX.  FB! 

Mike WN2A  -- Many great comments on MDS in its various forms. 

Philippe F6GUH is a FB homebrewer.  

Mike EIOCL -- Always great to talk on the air with an old friend. 

Walter KA4KXX -- I checked into the Sunrise net!  With my HW-101!  Thanks Walter. 

Farhan VU2ESE -- Watched our interview with Phil W1PJE

Phil W1PJE was an SWL with an old Halli receiver.  VOA?  Boo!  But Radio Marti is BACK! Also, the hydrogen line from the cosmic dark ages has red shifted to... 7.1 MEGA hertz!  So LISTEN UP! 

Phil W1PJE with a Halli and the Haystack Observatory Dome

Antenna Options and Views from the Terrace of SolderSmoke Shack South

Above is the view to the east.  North-east to Europe will be up to the left.  Straight out to the east gets me across the Atlantic to Central Africa.  

Here is the view looking south.   All of South America is down there, followed by Antarctica. Then up an around the pole to Sumatra and Borneo.  I can hear the Indonesians quite well on 15 SSB.   

Looking west.  Central America, then lots of Pacific Ocean all the way to Western Australia.  I have worked VK6JMS who is in the northern part of Western Australia, in "The Kimberly."

Here is the view to the north-west.  You can see how the top floor of our building blocks most of the signals from the U.S. and Canada when the antenna is at the terrace level (where it is now).    

I think I will stick with simple 1/4 wave verticals.  There is a lot of wind up here and we are not in the apartment about half the year.  I wouldn't want a Hex Beam to get blow over, especially when we are not here.  Simplicity is a virtue.   I think I can get the antenna above the top floor of our building by mounting it (base of the antenna near the top) on the support beam (for a sun shade) shown here.  This should greatly improve signals to and from North America. And I could easily take it down before we leave without having to climb up onto the roof. 

My Hanmilt HK 22 Drone -- Video and a still picture

This is the beginners's drone that I was using in the Dominican Republic this past winter.  It was really great.  The hover capability was amazing -- this made it very easy to learn to fly.  If it looked like I was getting into trouble, I would just go up a bit, hover, and figure out what to do. Obviously I could not do this with a fixed wing R/C plane.  Photography was excellent. See picture below -- I took this shot from my drone this winter.  I have a video on the Patreon channel.  

I flew this thing dozens of times, and only had one crash.  It was very minor.  I am still using the original propellers. 

The brand names change on these things very quickly, and Hanmilt might not be available anymore. But there are a lot of drones like this.  I paid about $100.  

I think my next drone will be a DJI drone.  But this will have to wait until I return to the Dominican Republic in June (I am in the FAA's "No Drone Zone" around the national capital.) Here is a really interesting video on DJI: 

https://www.youtube.com/watch?v=weDjwOyZaMc&t=225s

Falcon 9 Rocket Flies Over the Dominican Republic -- February 18, 2025

Just 30 minutes prior to this, my wife Elisa happened to see on Instagram a map showing the flight path of the Falcon 9. We didn't know that this was coming! I checked and got a live feed from Cape Canaveral of the launch. I figured we might see something if we looked to the north-west. Wow, did we. The Falcon 9 put on an amazing display. On January 25, 2025 we had seen a meteor-bolide fireball on a similar track. That was quite something, but this was really amazing. You can hear our excitement in the audio.

Thr bright object is Venus. The rocket appears to turn off its engines shortly after (from our point of view) it passes Venus.

Light Beam Communication from the Dominican Republic?

Mike WN2A sent me the PIC board to generate the CW for my "Lil Slugger" Doug DeMaw transmitter.  Then I started wondering about having a light source flash with the CW.  Mike recommended some super-bright green LED's.  I had a big broken flashlight with me (the benefits of junk!) so I put all the parts together and hung the light in the window of my seventh floor shack.  Last night as Elisa and I walked the dog, I looked back from a quarter mile south.  The video above shows the scene. The cell phone camera understates the brightness.  

The video above shows the rig in action (but with the bulb on the shelf).   Note the PLJ freq readout, the SWR meter and, of course, the green bulb.  

I half joked with Elisa that I would love to get a reception report on the light beam.  This is not all that far-fetched.  We have an email address in the CW message, and the light beam is aimed to the south, across the open Caribbean.  

All of this reminded me of an article by Rod Newkirk of some light beam communication that he engaged in in Indonesia during World War II.  Great story: 

https://soldersmoke.blogspot.com/2024/05/a-light-beam-qso-in-hollandia-christmas.html

First 10 Meter AM Contact from Hi7/N2CQR

I threw this in the bag on the way to the DR, almost as an afterthought.  But I am glad I did.  Today, watching reports on my 10 meter CW beacon (Mike WN2A provided the keyer),  I noticed that my signal was unusually strong.  At W3POA I was 7 db above the noise.  At DF2CK I was 4 db above the noise.  So I switched to the 10 meter AM rig (which is a converted GE brand CB rig) and worked John G3YPZ (see video above).   I was running about 5 watts to a quarter wave vertical.  But the signal reached the UK. 

Here are some details on my rig: 

https://soldersmoke.blogspot.com/2025/01/looking-for-contacts-on-10-meter-am.html

And https://soldersmoke.blogspot.com/2023/11/bill-n2cqr-goes-citizen-band.html

Thanks John!  

Fireball (Meteor) Over the Dominican Republic

Click on the link below to see the video

https://www.tiktok.com/@william.de.jesus01/video/7464040455185993002

I had been telling Mike WN2A how I had put a little red LED on my beacon (he gave me the keying hardware) and that I was hoping to put the LED in the window of my 7th floor shack.  I want it to serve as a kind of CW "lighthouse." We are, after all, close to the ocean.  I thought it would be cool.  Last night, soon after sunset, Elisa and I went out to walk the dog and to look a my little light.  

Well, as expected my little light was too small.  But HOLY COW,  it had us looking in exactly the right direction at exactly the right moment.  At 7:09 pm on January 25, 2025 a very bright, green, long-lasting fireball streaked across the sky from North to South (the guy in the clip above got the direction wrong).  It was throwing off fragments.  One kid in the neighborhood saw it.  And soon Instagram lit up (!) with reports and videos.  I filed a report with the International Meteor Organization: https://fireball.imo.net/members/imo_view/event/2025/516  It was all very cool.  The tiktok clip (above) has a collection of some of the best shots.  Just click on the link below the picture.  

I hadn't seen one of these since March 1995 (I was in the Dominican Republic then too!):  

7 MARCH 95 EVENING: POSTED ON CIS:

Also observed a pretty spectacular fireball in the North (near Polaris) at about 2330. So bright I thought it was a skyrocket. Very slow moving looking like pieces falling off it.

The 10 meter Beacon at HI7/N2CQR (and reception reports)

Above is the 10 Meter beacon at HI7/N2CQR.

The first one to hear the beacon was Dean KK4DAS in Northern Virginia, within hours of it going on the air. Here is Dean's recording of what he saw and heard:

Later, Mike WN2A heard it. Pete N6QW in California may have heard it too. A number of stations are reporting reception via the Reverse Beacon Network (RBN): It is being picked up almost daily (gray-line?) by Rico DF2CK who has an amazing station in Germany. K1RA in Warrenton Virginia (also an amazing receive set-up) is also picking up the station. W3OA in North Carolina is also hearing it and reporting by RBN. TI7W in Costa Rica has also heard it. Sadly, RBN is kind of clunky with beacons -- it seems to obstinately insist that I am in Northern Virginia.

Rico DF2CK writes:

Hi Bill,

thanks for info. 3 Watt can be loud on 10 if condx are good :)

The west direction skimmer setup on 10 m is a 6 el Yagi into a SDR with
AD9255 adc and XC7Z020 fpga.
A design by Pavel Demin which I am testing for a while now.

Enjoy the Caribean, here its minus 2 C and boot high snow.

73, Rico
DF2CK

Check out Rico's amazing station here: http://df2ck.de/

Andy K1RA wrote from Warrenton (Northern Virginia): 

Hi Bill

  Cool on spotting your beacon.  With good conditions I'm surprised you're not being heard elsewhere.

  I'm running a multi-band, multi-mode skimmer for CW, FT8, FT4, WSPR & JS8CALL continuously and simultaneously covering 160m-6m, 24x7 with Redpitaya SDRs and KiwiSDR/RaspSDRs

https://docs.google.com/presentation/d/1NPwjQe1am2Ym5GMV8L2V8fnQ_W9J0EbH/edit?usp=sharing&ouid=103988113912782027869&rtpof=true&sd=true

15 minute map view through PSKreporter here:

https://pskreporter.info/pskmap.html?preset&callsign=k1ra&timerange=900&hideunrec=1&blankifnone=1&hidepink=1

73 & good DX'ing!

andyz - K1RA

SolderSmoke Podcast #256: HNY SKN, LA Fires, Barkhausen! Southern Cross, Homebrew vs. Kits, AN762 Kit, Woe, Beacon, ARRL Kids, SDR Build, DC RX videos, Pete Hacked! Power alternatives, KWM4, Mailbag

A Tale of Woe! 

SolderSmoke Podcast #256 is available: 

Audio:  https://soldersmoke.com/soldersmoke256.mp3

Video:  https://www.youtube.com/watch?v=NYuEhljOtAQ

Travelouge:  From the DR.  

Happy New Year! 

Fires in LA.  

Dean:  Breaking the Barkhausen criteria.  

Seeing the Southern Cross for the first time in 30 years. 

For all three of us:  The SolderSmoke Homebrew Challenge.  And assembling a kit. https://soldersmoke.blogspot.com/2025/01/some-history-of-homebrew-ham-radio-from.html

https://soldersmoke.blogspot.com/2025/01/the-magic-that-only-comes-from-radio.html

https://soldersmoke.blogspot.com/2025/01/steve-g0fuw-talks-homebrew-and-kits.html

________________________________

Bill's (Southern) Bench: 

-- SKN with QCX given to me by Bob.  Thanks Bob! 

-- Finishing up the AN762 .1kW amplifier.  Socketry and relays.  Working well.  

-- A tale of woe:  Some difficult troubleshooting on the 15-10 rig. Intermittent oscillation.   Naturally I blamed the TJ DC RX AF amp.  Spent a lot of time working on that amplifier.  But problem always returned.  Started looking at output from carrier osc/BFO.  Waveform weird. Then weirdness disappeared and so did the whooping.  So I rebuilt the entire carrier osc/BFO/ mixer board.  Went back to singly balanced 2 diode mixer.  Used LTSpice for the oscillator amp.. No more whooping.  Turning the diodes on and off  but not quite 7 dbm...  Should I be concerned? 

-- A 10 meter beacon!  28.233   Please listen. Send e-mail reports.   Thanks to WN2A.   

-- Antenna thoughts.  Getting a tripod.  

The HI7/N2CQR 10 meter Beacon

_______________________________

SHAMELESS COMMERCE!   Mostly DIY RF!  Lots of useful kits and boards there.  I have used their TIA boards.  Todd K7TFC is one of us.  FB store. 

Become a SolderSmoke patron.  We need the help.  Homebrew is under seige!  We are one of the few sites, blogs, podcasts that are promoting it!  Help us!  

Buy stuff from Amazon and E-bay using the links on our sites. 

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

Dean's Bench: 

-- ARRL kids day -- Exhausting.

-- VWS Makers SDR receiver build.  

-- High School DC RX Build news. How to watch the videos.  

_______________________________

Pete's Bench:  

-- Hacked! 

-- Power Alternatives. 

-- Thermatron Finals

-- KWM-4. 

__________________________

Mailbag

Dave Newkirk W9BRD (son of Rod).  Great comments on homebrew radio. And a great picture. 

Derek N9TD built the DC Receiver.  FB Derek! 

Peter VK2EMU at 39C in Australia.  HOT! 

Drew N7DA -- Some great comments on kits vs. homebrew. 

Tommy SA2CLC has a nice video about fixing the cavity resonator in his HP8640.  Respect! 

Ben KC9DLM sent good presentation from India: https://github.com/kholia/talks/blob/master/Dhiru_My_RF_Homebrew_Adventures.pdf

Scott KQ4AOP and Derek N9TD offering to 3D Print PTO coil forms.  FB!  

Donnie WA9TGT on the beautiful signals from DC receivers. 

Chuck KE5HPY's FB Altoids DC receiver. 

Todd VE7BPO:  POPCORN ELECTRONICS IS BACK!  Thanks Todd.  And thanks Vasily! 

Jim KA4THC has his uBITX on the air and is making contacts!  

Farhan VU2ESE fond memories of homebrew dinner with Wes and other HB Heroes (on the blog). 

Charlie ZL2CTM -- About his new Pelican Case SSB rig. 

Walter KA4KXX.  All new hams should build a transmitter. 

Buzz W3EMD  A nice QSO on 10 and then a shout out to the Old Military Radio Net

Stations that heard my beacon and reported to RBN

A Saw the Southern Cross (Crux) This Morning (first time in 30 years!)

You can see it (above) in the picture I took this morning, with my Iphone. 

I think I last saw this important constellation more than 30 years ago.  From my observation log: 

DECEMBER 9 1994. MORNING. Went to Parque Mirador Sur near Hotel El Embajador at 5 a.m. Confirmed that I have been looking at the Southern Cross. Below Corvus, Head of the Cross is on a line from Alpha and Beta Centauri. Base of Cross is "three thumbs" from horizon. I calibrate my thumb with Mars and Regulus at 2 degrees. That puts base of cross at 6 degrees off horizon. My Horizon is (90 -18.5 = 71.5 South. So 71.5 - 65.5 BINGO! Agrees with star map declination for Southern Cross. Also Right arm of cross is faint as indicated on star map. Alpha and Beta Centauri off tothe left. Alpha looks red. Beta seems to have two other stars around it. Eureka: Following the line from Alpha and Beta Centauri to the head of the cross, I found a very distinct circular cluster. I think this is the Jewell Box - NGC 4755 (open cluster). Still trying to figure out the constellation (Argo?) that lies to the right of the cross. Looks to me like the false cross. It is bigger than the Southern Cross. Mine seems to have a cluster off the right arm and the left arm has a dimmer star near it. A good morning! (LATER FOUND THAT MY CLUSTER WAS GLOBULAR CLUSTER RNGC 5139. I HAD MISIDENTIFIED ALPHA AND BETA CENTAURI.) 

Here is what Heavens Above predicted for this morning from Punta Cana: 

 

 

A Tale of Woe -- Troubleshooting my 15-10 Rig in the Dominican Republic

-- Problem first showed up as a low level oscillation in the background.  Annoying. 

-- I suspected the simple AF amp from the TJ DC RX project was oscillating.  Wasted a lot of time. 

-- Isolated the problems by cutting off all of the RF input to the SBL-1 mixer. 

-- While watching the carrier osc signal, noticed that the hum appeared as the waveform got fuzzy. 

-- I had used the osc/product detector circuit from the BITX 20. 

-- I had added an amplifier stage to get the signal to higher level. But it was poorly designed. 

-- After some struggle, I decided to rebuild the osc/mixer board. 

-- Redesigned amplifier stage using LTSpice. 

-- Changed from an SBL-1 mixer to a singly balanced mixer like in the BITX 20. 

-- This worked well.  Hum disappeared. 

-- But I had neglected to put the .001 uF cap to ground from the AF port! Thus the cartoon! 

-- This is a very important cap.  Circuit was a lot more balanced with this cap in place. 

-- Noiticed that output on 10 was only about 25 watts PEP, while on 15 it was around 100. 

-- Checked input to final amps.  Input on 10 was a lot lower.  

-- Tweaked the 10 meter bandpass filter and got the output on 10 up to about 80 watts. 

Re-Built board for carrier osc/BFO and mixer for TX and RX

Bill N2CQR Builds Yet Another Mythbuster Transceiver

 This one is for 20 meters (no need for 75) and will go to the Dominican Republic.

6 crystal filter at 5.2 MHz. VFO from old Yaesu FT-101 Termination Insensitive IF amplifiers using boards from Mostly DIY RF No RF amp ahead of the mixer. First mixer is homebrew diode ring. Bandpass filter has 4 LC circuits. Steep skirts. Low insertion loss. Bal Mod/Product detector has two diodes (singly balanced) Carrier osc is crystal controlled and homebrew. Audio amp starts with a 2N3904 amplifier followed by an LM386 board. Transmitter portion will be done next.

The crystal filter as seen on the Antuino

Filter on the blank board. 

Bandpass filter (-20 db = 0)

VFO box, carrier osc, Bal Mod/Product Detector, AF amps

The Antuino looks at the Crystal Filter

How to Organize a Small Shack

A YouTube comment from Paul VK3HN sent me back to "The Spirited Man" YouTube channel, and one of the first things I found was this video about how to organize a small space.  This is very relevant to my shacks in Virginia and in the Dominican Republic. 

Lots of good ideas here, but that propane heater kind of scared me.  And it seemed inconsistent with concerns behind the fire-preventing garbage can.  What do you folks think? 

Thanks Paul. 

 

The Tropics Defined: Sun Directly Overhead on July 31 in Punta Cana DR

July 31, 2024  12:30 Local Time

Check out the shadow at my feet.  The sun is directly overhead.  This happens here on July 31, shortly after noon.  We define "the tropics" as the area of the earth at which -- as some point in the year -- the sun will be directly overhead.   Here we are at about 18 degrees North latitude, so for us, the overhead date is July 31.  We are definitely in the tropics.  A good graphical description of what is happening appears here: 

https://www.suncalc.org/#/18.5548,-68.3853,12/2024.07.31/12:37/1/3