Crystal Radios from Heaven, Regens from ?

Yesterday I was describing the heavenly sounds coming from my crystal radio. In a minimalist mood, this morning I fired up (an appropriate term!) my ET-1 regen rig. This is the single FET transceiver described in earlier blog articles. The contrast with yesterday's experience couldn't be starker. Instead of Gregorian chants, I was greeted by the screeches of excessive regeneration. The crystal receiver seemed to WANT to demodulate signals, the regen required all kinds of adjustment and coaching and, it seemed, black magic. All this made me think that while the crystal sets are heavenly, the regens seem like they are from the other place.
There is a Roman ham who has said he will try to have a contact with me using this ET-1 rig. One will be enough, then it will be back to direct conversion and superhets for me.

Gregorian Chants on a Crystal Radio

Last week I was telling Billy about crystal radios, and I followed-up by digging up the one we built in London. I don't have my really good, HI-Z headphones, but even with fairly LO-Z cans, I could pull Vatican Radio's 1530 kHz signal out of the ether using just a Germanium diode, a coil, a variable cap, and my all-purpose end-fed wire antenna.
I live very close to Vatican City (see above), but I think their AM transmitter is out of town, to the North of Rome. I visited the Wiki on Vatican Radio. Very interesting. Turns out that the Jesuits run the radio stations. Go here for a virtual tour:
http://www.vaticanradio.org/museo_tecnico/it/gal_fot_24.asp
It took me a few minutes to hook up the 4 parts of my crystal receiver; it seemed kind of fitting (and a bit eerie) to be rewarded with the faint sound of Gregorian chants.

Five. Two. Seven. Six. Three. Six. Nine. Eight......

Nick, KB1SNG, reports that he was brought into ham radio via an interest in the infamous "Numbers Stations." He sent along a link to a very interesting site on this subject:
http://www.simonmason.karoo.net/page30.html

Italian Experimental Station in the Good Old Days... And Today!

Today (he tells me it is 50 years later!) my friend Gianfranco is on the air as I0ZY.
Transmitter back then was homebrew except for a Geloso VFO purchased for 7000 lira (11 dollars at the time). Tubes were 6J5's and 6V6's. It ran AM. Two 807's in the final with 600 volts on the plates. Two 6L6's running AB2 as the modulator. His mic was salvaged from an old wire recorder. Except for the VFO, everything was from WWII surplus.
On the receive side, he had an HRO 5 by National that he picked pretty much in the same flea market area that we visit today. It was in such bad shape that they gave it to him for free! With a lot of patience and persistence, he was able to get it to work on 20 meters. Gianfranco clearly had The Knack!

And he still does! He now has a wonderful company (SPE) that manufactures in Italy some very advanced linear amplifiers. He is the designer and creator of the Expert 1K-FA. Check out this video on his company and his product:



Here is the link to the site for the Expert 1K-FA:
http://www.radio-ham.eu/Expert1K-FA.htm

SSSSSSolder SSSSSSSmoke's SSSSSSS problem

In SolderSmoke 109, I did a little experiment. Normally I do some audio processing using Audacity's Equalization option. In all of the recent episodes, I have been using an equalization curve similar to the one shown above. I drop off the low frequencies (to get rid of the Popping P sounds) and I put a notch at around 3500 Hz in an effort to get rid of the problematic SSS sounds. I had my doubts about the effectiveness of all this. Partly in an effort to save time, SolderSmoke 109 I dispensed with the processing. I immediately got a couple of e-mailed signal reports saying that the nasty SSSS sound was back.
I really can't hear it on my computer. This may be related to different sound cards. And some high frequency hearing loss that I picked up on the rifle range may be involved.
If you can, please compare the sound quality in SS108 with that of SS109, and let me know what you think.
Dean, WA6P, and Bill W7AAZ, going to send me a passive audio filter that we hope will help.
On a similar note (!), I am looking for a circuit for a simple audio signal processor for use with my DSB rigs. I need something simple that will provide both clipping (probably via the standard two diode arrangement) AND audio frequency selection. The ability to put upper and lower limits on the audio frequencies is important in DSB rigs, because they lack the crystal filters that do most of this work in SSB transmitters.

SolderSmoke -- The Book. Table of Contents

As promised in SolderSmoke 109, here is the Table of Contents for the new SolderSmoke book.

CONTENTS

Preface

Chapter 1 Electrically Inclined – Tales of an Electromagnetic Youth
Electrons and Electricity
Radio Waves
Some Basic Equations
Einstein in the Transformer
Semiconductors

Chapter 2 Off-the-Air—Amateur Radio Goes Into Hibernation
Junctions and Diodes

Chapter 3 Tropical Rebirth—Ham Radio in the Dominican Republic
The Lowly Capacitor
Resonance and Oscillation
Series and Parallel Tuned Circuits

Chapter 4 Boatanchors in Virginia—Back in the U.S.A.
Transistor Amplifiers
Mixers
Modulation: AM, DSB, SSB

Chapter 5 Mid-Atlantic Outpost—Amateur Radio from the Azores
Balanced Modulators

Chapter 6 Urban Radio—Solder Smoke in Central London
Amplifier Loads

Chapter 7 Rome—Secret Radio in the Eternal City
Feedback in Amplifiers

Chapter 8 Conclusions—A Brotherhood Without Borders

Acknowledgements

Index

To order: http://www.lulu.com/content/paperback-book/soldersmoke/6743576

SolderSmoke Podcast #109

http://www.soldersmoke.com

June 7, 2009

Violin gig in Rotterdam
June 2 Parade in Rome
Why do we use Rl=Vcc^2/2Po for Class C amps?
     NA5N article, EMRFD, SSDRA, LTSpice
Radio Signals from Jupiter and Io (on 17 meters)
VK2ZAY's X-Rays
Jeff Damm, WA7MLH:  Homebrew Hero
Tim Walford's Constructor's Club:
     Floor Polish as PCB Laquer
     Numbers Stations (very timely!)
SolderSmoke -- The Book: Very rapid delivery, even to UK
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