Telecom Milestones

 AMATEUR  RADIO

A BRIEF HISTORY

 

From the first days of Wireless Telegraph (1900), many experimenters with basic knowledge in electricity and electro-magnetics were eager to build by themselves wireless telegraph stations. Technical magazines published articles with instructions to build Wiireless Spark-Gap Transmitters and Ctrystal Receivers. Soon after, electrical materials distributors and stores began to offer parts for do-it-yourself wireless equipment.

The picture from: 

http://www.uv201.com/Photo%20Pages/ham_3.htm  shows a wireless station of hobbyist around 1912. The equiment on the shelves include loose-coupler tunner, crystal detector, spark-gap transmitter using a car ignition coil for High Voltage, a Morse Key and headphones.

 

Until 1912, there were no regulations in the USA regarding the operation of wireless stations. The wireless hobbyists that later on were called Radio Amateurs, operated freely and quite often caused interference to commercial and maritime wireless communicatrions.

MURDOCH   APARATUS

       CATALOG  No. 14

    W.M.J Murdock Cmpny

           Chelsea, Mass.

The Radio Act of 1912 covered all the wireless telegraph activity and in 1913 a Radio Call Program was published. Each amateur station had a three characters Call Sign. The first figure was for the district plus two letters. For instance:  1WH was the call sign of Hiram Percy Maxim, a most famous founder of the ARRL.

 

To avoid the interference caused by radio amateurs to the commercial and maritime telegraph stations, radio amateurs were allowed to operate at wavelengths shorter than 200 meters (1,500 KHz). At that time, shorter wavelengths (higher frequencies) were considered as inefficient for long range wireless communication. Amateur radio activity on the short waves spread all over the world and soon it was proved that short waves are ideal for very long range communication, even with the low power transmitters in use by amateurs. Radio amateurs discovered the reflection effect of the ionosphere layers on the propagation of shot waves around the globe.

 

Radio amateurs were involved in the development of radio communication since the days of spark-gap transmitters, through the vacuum tubes era to the existing semiconductors, integrated circuits and digital era. 

 

Starting with Morse Code mode at the Wireless Telegraph Era, radio amateurs operated AM (Amplitude Modulation) mode at the beginning of the Vacuum Tubes Era. The Morse Code is called CW (Continious Waves). The AM mode was replaced by the more efficient SSB mode in the 1960's. FM mode is used on the VHF UHF bands.

MY STATION

GALLERY OF HAM RADIO EQUIPMENT

HAMMARLUND HQ-129-X General Coverage Communication Receiver (1948-9)

 

It has a continuous coverage from 540 KHz to 32 MHz. The reception modes are AM and CW. The BANDSPREAD DIAL enables fine tunning on the 80, 40, 20 and 10 meters amateur bands. It was produced from 1946 until 1952. 

 

          TUBE LINE-UP

6SS7                    RF Amplifier

6K8                      Converter

3 x 6SS7              1st, 2nd , 3rd iF Amplifier

6H6                       Detector

 

6SN7GT/G          1st Audio Amplifier and “S” meter

6V6GT/G            Audio Power Amplifier

6SJ7                     B.F.O

5U4G                  Rectifier

VR105                 Voltage Regulator          

DRAKE TR-4 (Was in use in my station since the beginning of the 1970's)

DRAKE RV4

 

Remote VFO - Speaker and power supply cabinet for the TR-4 Transceiver

ICOM  IC-746PRO 100 Watts HF/6m/2m Transceiver

ICOM IC-22A  10 Watts 2m Mobile Transceiver

SOVIET ARMY HF RECEIVER R-311 (1960's)

BAO FENG UV-5RA, 5 Watts VHF-UHF FM Handie-Talkie 

ACCESSORIES

LAFAYETTE CERAMIC DESK MICROPHONE  99-4607

MFJ HF/144/440 MHz SWR WATTMETER

                    MODEL MFJ-864    

EAGLE SWR - Field Strength Meter C3042

BENCHER BY-1

VIBROPLEX "ORIGINAL" Semi-Automatic Key

Serial No. 13980 (1940)

Straight Key J-37 (WW2)

MY ANTENNAS

BUTTERNUT HF9V 80-6m 9-Band Vertical Antenna

With a pair of 1/4 wave radials for every band from 80m to 6m.

MULTI-BAND DIPOLE

 

Mounted inside the roof, covering 40m to 6m bands.

 

The coil at the center is made of RG-213 and acts as a BALUN.

GALLERY OF ANCIENT  PICTURES AND DOICUMENTS

Final works on my homemade 10 Watts modulation amplifier, with push-pull 6V6's.

 

I was a teenager at the high school (1950).

NC-200 Reciver used with my homemade 807 tubes transmitter (not shown in the picture) - 1960's

                                               

DRAKE TR-4 transceiver with the RV-4 remote VFO - 1970's

The first page in my first Log-Book (Dec. 8 1952)

 

My transmitter was homemade 20W with two 6L6's and a crystal oscillator. The receiver was home raadio with short wave bands plus a homemade BFO circuit, to receive CW. A windom antenna completed the set.

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