Science Fair Light Beam Communications in 1960s

Hi Bill!  This Bob Schubert, KC4FNE in Blacksburg Virginia just wanting to say hello and taking the opportunity to say "Thanks" for the SolderSmoke Series.  I have to let you know your podcast accompanies me as I do my early morning exercise regime.  Before SolderSmoke, I would begrudgingly get out on the track every other day.  Now I'm out there just about every morning listening to a new episode.  I'm not sure what I will do once I exhaust all of the episodes?  Normally I would cover my obligatory 2 miles in 45 minutes, now I'm looking for excuses to stay on the track so as to complete a one-hour or so episode.  When I'm listening to it in the car, I find myself circling the block just so I can finish a podcast.  It has also prompted me to purchase the SolderSmoke book.  I'm thoroughly enjoying the book as we seemed to have both grown up close to the same timeframe and our early lives led as "geeks."  If you interetsted in what an "old geek" is up to now, point your browser to http://www.lumenhaus.com/  This is a solar powered house done by a team of architecture and engineering students/faculty I was involved with.  If you ever find your way to Blacksburg and are interetsed in our Lumenhaus, I would be happy to provide a tour.

I've included a photograph of me taken at Orange County High School in the mid-60's with a science fair experiment "Talking on a Light Beam." While not quite in the 478THz range of the high-power LEDs it was up there!  While modulating the filament on a flashlight I would be hard-pressed to go 95ft much less 95 miles.

Best, Bob Schubert KC4FNE

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Video Model Rocketry

Our plan is to strap a key-chain video camera to the center of gravity on this mean green machine.  Using Duct Tape (of course).  Kind of like this guy did:  

http://www.teamten.com/lawrence/projects/video-camera-on-model-rocket/


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Bell Labs: Similarities in Wave Behavior

John N. Shive rocks the universe with his 1959 wave machine.  We saw this device some time ago in a video in which Dr. Shive explained standing waves.  Thanks to Armand WA1UQO for alerting us to this gem.  

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Real DX: Hubble's EXTRA Deep Field

http://www.clarksvilleonline.com/2012/09/26/nasas-hubble-space-telescope-takes-deepest-image-of-the-universe-to-date/

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SSB Generation: Ideas from Around the World

I liked this thread on the EMRFD mailing list.  The question of how best to generate SSB is very interesting, and I also liked the global scope of the Q&A:  Peter in Hungary asks the question, Farhan in India and Allison in the U.S. respond.   

 On 9/25/12, ha5rxz wrote:
When generating an SSB signal from audio and a 9 MHz carrier which would be
the best mixer to use?
a) A high-level ring bridge mixer such as the SRA-1H
b) An H-Mode mixer using an FST3125 chip
c) An H-Mode mixer using a 74HC4016
d) Something else
Note that this mixer will not be used to demodulate.
Peter HA5RXZ
...................................
Ashhar Farhan wrote:
In my experience, if you keep the audio level low enough, it is
difficult to beat a simple two diode mixer.with a 10 db attenuator in
the output. Having just two diodes makes balancing of reactive as well
as resistive differences of the two diodes quite trivial. Schottky
diodes are best.
One thing, I did discover though is that the balance should be to
minimize the harmonic distortion, rather than just the carrier
suppression.
What we are shooting for is to keep the In-band IMD down. Carrier
suppression is just hygiene. So, you will want to tune in to the
signal, modulating it with two tones and see it on a audio spectrum
analyzer (freely downloadable from the net) and try getting the third
spike down.
Though the 'packaged' mixers don't give you the needed control for
hi-fidelity, for trivial usage, NE602 is pretty good. Just drop it
into the rig and live with what you get (which is not bad at all).
The best resource is the chapter on phasing receivers and transmitters
in emrfd. Rick is the guru. I hope he joins this thread.
 
- Farhan
............................................
FROM KB1GMX: 

I'll weigh in..

Yes, they all work. You need a provision for adjusting carrier balance on some but anything over 40db will be good.

I've used 602/612s, SBL-1, SBL-1H, diode rings, and even varicap
diodes (there is a design using them in capacitively balanced 
a modulator from many years ago. They all work if the levels are correct.

These days I use the sa612 for simple designs, SBL-1 with a 50ohm 
pot added for balance for better radios and the 4 diode ring I've 
used many times as its uncritical, needs only one untapped 
transformer and easy to make. Most of those are listed in the 
older 1975 through current handbooks and EMDRFD.

If needed I can post to the files section a few designs but 
they are all textbook and all are capable of good results.
In just about all the diode modulator cases a fairly strong 
carrier (5mW or more) is needed and the audio will be about 
10db lower for very good result. The active devices like the
ca3028(and friends), SA612, MC1496 the levels for the carrier 
and audio must be matched accordingly for the device. You can 
look at the output with a scope and get a first order eyeball 
call on quality (no carrier and no clipping or limiting) and a
receiver (any your ears) will tell you if its right.

Allison

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

SolderSmoke Podcast #146

SolderSmoke Podcast #146 is available. 

http://soldersmoke.com/soldersmoke146.mp3

Sponsored by: SMT Solutions:  http://www.smt-solutions.net/

September 23, 2012

Trip to the Dominican Republic:  Puerto Plata and Samana
Evading Hurricane Isaac
Honda Accord as an emergency generator 
On the air on 75 and 40 AM
17 Meter Azores rig works...THE AZORES! 
Working (STILL!) on 20 meter DSB rig.  Soon to be JBOTed
Building model rocket with Billy
Book review:  "Martian Summer" 
Einstein on staying young
Primo Levi on QRP
HOT IRON:  G3ROO's Regen wins West Country prize 
Commodity Investment Opportunity: SILVER MICA! 
MAILBAG: 
SolderSmoke is on 478 THz in Salt Lake City
WA3EIB's HT-37
Radio-Erotica in Hallicrafters Ad



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An Ode to Old-time Radio by WA3EIB

I didn’t have much growing up but I still had fun!

Towers of wood and Pipe that reached close to the sun.

Antennas of aluminum and wire seen many blocks away.

C.W. into the wee hours of the night. Hot coffee, now I’m awake to stay.

Many pleasant dreams as the radio cooled and the crickets chirped me to sleep.

Nestled between Foreign Broadcast Signals, and oh my dinner,  I forgot to eat.

But YES, I still had fun!

A cigar box full of crystals and an antique key, I was determined it was one more watt that I need.

Lost them, found them and lost them again but, I still had fun indeed!

Sun rising now, Europe on the line, Shadows short and Africa began to shine.

Orange glow at dusk the ocean islands start to appear, near midnight now and its Russia I hear.

Perhaps these days may all be but gone but my equipment and dreams continue to live on.

And YES, I still have fun!    HH

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

SolderSmoke in the Red Light Zone

Hi Bill,

I've been a listener to Soldersmoke for several years, now and look forward to the podcasts and postings.

This past weekend our group of microwavers in the Salt Lake City area participated in the 2nd half of the ARRL "10 GHz and up" contest and, for the fun of it, we decided to get on the highest amateur band, the one marked in the rules as being "275 GHz and up."  In our case, it was around 478 THz - also known as "Red" - being emanated from high-power (20+ watt) LEDs.

Attached is a picture taken from my location at about 9300 feet elevation (grid DN40cx) taken from a location near a minor bump known as "Bountiful Peak" 10 miles or so north of Salt Lake City where I was accompanied by Gordon, K7HFV and Gary, AB1IP.  At the other end of the path (the red dot at the far end of the red shaft of light) was in DN31it was Ron, K7RJ and his wife Elaine, N7BDZ located at about 5700 feet elevation near the remote northwestern Utah community of Park Valley, over 95 miles distant.  While this isn't our farthest DX (that would be a bit over 173 miles) it was still fairly substantial and gave us the ability/excuse to test some new, updated gear that hadn't seen much light in the field.

In doing our testing, we needed an audio source other than our voices so I'd brought along an MP3 player so that I could step away from the gear and still provide a constant source of audio.  Among that which was played across the link - the quality of which was extremely good, by the way at about 50dB S/N at full LED power - was your voice from a Soldersmoke podcast.

FWIW, we also established 2-way communications using cheap, low-power laser pointers and while they did work, the link was very inferior owing to severe scintillation (fading.)  For a bit more info on what we did you can read here:

http://ka7oei.blogspot.com/2012/09/throwing-ones-voice-95-miles-on.html

and if you want more, you can follow the link at the bottom of the page.

Anyway, I thought you might find that interesting, if nothing else...

73,

Clint
KA7OEI

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Boatanchor Dreams

Greetings Bill and Fellow Solder Melters,

Back in 1965, I bought a brand new HT-37 from a radio store in Pittsburgh, Pa.

It had been tucked away by the owner for his own personal collection.

He finally softened and sold it to me.  The Hallicrafters HT-37 became by Big Dog for many years.

In 2005, I fell on some difficult times and sold it. I regretted the departure moments after the exchange.

Well, finally after lots of searching, the right unit came along.

Here are a few pictures of my excellent E-bay buy.

I will begin to dig into the electrical status of the rig later this week but the unit seems well cared for and not abused. 

I will keep you posted. It will be happily married to my Drake 2B and Q-Multiplier after it passes muster.Yes fellow hams there are still gems out there for your collections. Just wait for the right buy and then go for it!

73’s  Harv -=WA3EIB=-

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

Photo by WA4KCY

Bill,
       I know you would appreciate this. Got an email this morning from a local ham who was getting rid of some "junk" radios, wondered if I or someone else could use them. Once I heard I got over there to pick them up. Among the usual, real junk was a Hammarlund HQ-110C receiver, in the original box and a Johnson Viking Ranger, also in the box. With all the manuals as well. The boxes are showing their age, the Ranger's being not much to look at. I am told neither works and haven't been looked at / turned for at least 20 years. What a find! They are very clean and complete, as far as I can tell.
The plan is to restore them to pristine condition and, hopefully, use them in one of the local museum as a working station.
 
Mike Herr
WA6ARA
DM-15dp

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Book Recommendation: "Martian Summer" by Andrew Kessler

I took this book with me to the Dominican Republic this summer, and I really enjoyed it.  Kessler has an unusual, very funny, self-deprecating writing style.  He is not a scientist nor an engineer, but he is given access to the inner sanctums of the Mars Phoenix mission, and spends an entire summer watching and documenting the work of the people running this mission.  

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

Amateurfunk -- Ham Radio in Germany in 1955

Ah, those were the days!  The bands were in good shape and hams built their own gear.  
Don't let the language barrier deter you -- this German language video is really a lot of fun and worth watching.  It provides a nice look at the hobby as it was 60 years ago. Thanks to Stephen and Michael for alerting me to this.    

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An SWL QSL

I always like to get QSL cards from shortwave listeners.   I suppose this has to do with my broadcaster tendencies.  I blame Jean Shepherd for this.  Owen heard my K2ZA DX-100 on 40 meter AM. 

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