LAFAYETTE KT-135
"Explor-Air" 4-Band Receiver Kit
Howard Armstrong
Inventor of the regenerative
feedback circuit, used in the Lafayette KT-135
Collectors still enjoy building and restoring regenerative receives such as the KT-135 today
The Arm Chair Traveler Might Hear: NHK, or Radio Russia today!
Radio Japan
NHK Tokyo
NHK (Nippon Houso Kyokai ~ Japanese Broadcasting Corporation) in Tokyo was founded in 1954. The author sat behind the microphones at the NHK studios in 1991
NHK Building Near Tokyo
NHK Studio Park Shibuya
My tour guide for the day
Inside the NHK studios
QSL Card NHK 1995
Mt. Fuji located on Honshu Island. The Beautiful Island Nation of Japan
Radio Moscow
What Short Wave Listener Can't say he or she has not heard Radio Moscow's them Midnight In Moscow!
Radio Moscow QSL Card Cric. 1966
Trans World Radio Bonaire Netherlands Antilles could often be heard on the KT-135
This KT-135 Recently sold on Ebay for $76 in less then perfect condition, so they can still be found.
More interesting Radio links
Who Invented the Super heterodyne Receiver?
Edwin Howard Armstrong the Inventor of FM Radio
Before we go into further detail about the KT-135, I'd like for you to look at a little radio history frist. When ever I teach a class of new comers who are enthusiastic about radio and electronics, I always make it a prerequisite that they know a little something about Edwin Howard Armstrong. I make everyone watch the PBS video "Empire of the Air, The Men Who Made Radio." In the video Edwin Howard Armstrong is one of the featured characters, he was born 1890 in New York City and died in 1954. In my opinion, Howard Armstrong was one of the greatest inventors and radio engineers of the 20th century. The basic design of the regenerative receiver that is used in the Lafayette KT-135 receiver was discovered by Howard Armstrong. By taking a radio signal and feeding it back into the same tube repeatedly, Armstrong found that he could create gain, there by strengthening a weak signal and make it stronger. At the same time this type of circuit was limited by the amount of gain it could produce, that is until the circuit finally broke into oscillation. In the case of our KT-135 the result of trying to turn up the regeneration control for more gain would eventually cause the receiver to break into a oscillation and give the listener with a pair of headphones on one bad headache from the squeal after hours of listening. On the other hand an oscillating circuit has it's advantages for an oscillator is nothing short of a small transmitter. Armstrong's discoveries made radio communications possible over long distances and he was nothing short of a genius at electrical engineering. He later went on to discover and produce the first FM transmitter and receiver, today FM reception is used in everything! Your TV receiver, your car radio, your hand held transceiver, your cellular phone all use FM radio.
Often Working alone in the attic of his parent's home, he invented the regenerative feedback circuit in 1912, named after him as the Armstrong oscillator. Then later he invented the process of super heterodyne conversion in 1918 by beating one radio frequency with another to produce a different frequency that was often easier to work with. This process of super heterodyne conversion eventually brought wireless communication out of the dark ages of spark gaps and Morse code and eventually into the living room of nearly every American as the era of broadcast radio began. Armstrong later went on to invent static free radio reception by shifting the radio frequency of the transmitter at a rate determined by the audio signal driving his transmitter. Better known as Frequency Modulation (FM) it is used in just about everything to do with communications in the 21st century. Your television, cellular telephone, police scanners, auto receivers and countless other consumer devices all use FM radio because it is static free. We all owe a debt of gratitude to Armstrong, yet I bet you can ask anyone on the street who the man was and you will get a blank stare. Armstrong received his patent for FM radio in 1933, however he was later financially destroyed by RCA's David Sarnoff who was making older technology amplitude modulated (AM) receivers and was reluctant to change to the new FM technology. RCA being the powerful corporation that it was controlled the broadcast industry at that time, RCA did not want to change over to the new technology invented by Armstrong. The Radio Corporation of American kept Howard Armstrong tied up in the courts for years until the inventor later committed suicide in 1954 by jumping out of his apartment and plunging to his death.
To learn more about Howard Armstrong
Visit PSB.org and get yourself a copy of Ken Burns: Empire of the Air, The Men Who Made Radio you won't be disappointed having your own copy.
LAFAYETTE KT-135
"Explor-Air" 4-Band Receiver Kit
TUNE IN THE WORLD!
$22.95
Life was just a littler a little simpler back in 1969
and yet that may not have been a bad thing either!
(2010 ~ 21st Century) We now live in a society today where young people are immersed in a world of X-Box video games, I-pods, instant world wide cellular telephone communications at their finger tips, blue tooth technology and a cellular phone in everyone's pocket. With all of this technology at hand, it's hard to imagine a youngster today taking a keen interest in short wave radio listening (SWL) as many of us old timers once had our ear glued to a shortwave radio in our youth. So what was the fascination about a wooden box with a three tube receiver in it that barely works that often broke into an oscillation giving the user wearing headphones a huge headache after many hours of listening?
~Nothing ~
~Yet Everything!~
The Lafayette KT-135 was nothing
short of a dream come true for a me when in my teenage years trying to
reach beyond the walls of my childhood bedroom to distance places far
away. At hand was the Exotic Orient, the essence of cherry blossoms right from
Japan! Europe, and the excitement of hearing the sounds from the BBC
along with the Chimes from Big Ben. "This is London
Calling,
The world service of the BBC in London." Radio Moscow and the
musical theme intro Midnight in Moscow could be heard every night of the
week. Radio Havana Cuba. In those turbulent times the
Vietnam war raged on (1969) in the far east and right there on my desktop from this
little amazing box! I'LL never forget Radio Peking (Now
Beijing) saying
one night
"People of the world unite! ~ Defeat the US aggressors and their running dogs!"
Good God almighty, I thought at a youthful age, someone out there hates us! I wonder how many of you received the little red book with the teachings of Chairman Mao from radio Peking like I did and big photos of Chirman Mao? Then later my hearing about EXPO 70 in Osaka Japan. NHK- Nippon Houso Kyokai! = This is the overseas broadcasting service of NHK in Tokyo." Little did I realize at the time that some twenty five years later I would actually have the opportunity to sit behind a microphone of the NHK studios in Shibuya near Tokyo where those broadcasts originated. For me this life long fascination with radio all started with this little box and three glowing radio tubes that warmed not only my room but my heart for life!
Osaka 1970 Toshiba / IHI Pavilion Expo 70
First learning of EXPO 70 from NHK via short wave radio, I listened with excitement using my Lafayette KT-135. At that time the best I could hope for was getting some stamps from Radio Japan. I found these in a an collection I've had all these years. The two center stamps actually came from Grenada showing the Toshiba IHI Pavilion illuminated, Expo 70 Osaka Japan.
Getting back to our receiver, the Lafayette KT-135 sold for a whopping $29.95 in 1969 with the optional leatherette covered wooden cabinet that sold for a whopping $2.85 cents. The advertisements in this summer catalog go on to say the "Building this kit is an absolute pleasure - it's so well designed you can't go wrong!"
How could you go wrong building a kit
with Giant Pictorials 24" Inches long by 18 inches high.
These pictures taken from almost four feet away !
The parts layout and schematic diagram were so easy to follow ~
Even a Cave Man could build it!
Lafayette "Explor-Air"
Wow just the name alone was enough
to entice you into becoming an explorer of the ether!
Tunes International Broadcast, Citizens Band, Maritime, Aeronautical and WWV Time Signals. All from a 4" speaker and sensitive circuit with 50C5 audio output stage and 12AT7 regenerative detector!
With only $22.95 and a 50 foot piece of wire for an antenna. You had four whole bands of fascinating programming and you literally had the world at your finger tips. Maybe life was just a littler simpler back in 1969 and yet that may not have been a bad thing either! We didn't need a stinking cellular phone, the internet or Skype. We still had to use our minds eye to picture these strange new lands far, far away. And if this was your first receiver as it was for many an SWL. I'm sure you will agree the Lafayette KT-135 did more then just open your ears to the world. The Receiver kit taught the builder about so much more, geography, world events, history, stamp collecting as well as basic electronics, radio technology, radio spectrum usage, time signals and more. Who would have thought such a small thing presented to a young person would have had such an effect on shaping young minds. Some how after many hours of listening I managed to QSL 50 countries with this little gem of a receiver. To say the Lafayette KT-135 had a profound effect on my life would be an understatement as it was the driving force for a life long passion and interest in radio communications. After spending a life time in radio and electronics and yet some 40 years later I'm still learning, still listening, and wishing I could only once again be 13 years old, building that first radio kit once again, ~a Lafayette KT-135~.
Now I wonder about future generations now and yet to come. What if anything will they be able to look back on and say they learned by using an Ipod, Xbox or Sony Play Station? Something tells me there is very little to be learned from a throw away device such as an Apple I-POD, hand held video games or Sony Play Station!
I wonder?
Carol L. Maher W4CLM
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