Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Microwave Magazine Article on 100 Years of Rvcr Design




 
The AM Forum
May 22, 2019, 11:21:24 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Microwave Magazine Article on 100 Years of Rvcr Design  (Read 336 times)
0 Members and 1 Guest are viewing this topic.
Tom WA3KLR
Contributing
Member
*
Offline Offline

Posts: 1910



« on: March 10, 2019, 09:43:23 AM »

Microwaves & RF magazine, October and November 2018, has a two part series titled 'A Selected History of Receiver Innovations Over the Past 100 Years:

https://www.mwrf.com/systems/selected-history-receiver-innovations-over-last-100-years-part-1
https://www.mwrf.com/systems/selected-history-receiver-innovations-over-last-100-years-part-2

Enjoy.
Logged

73 de Tom WA3KLR  AMI # 77   Amplitude Modulation - a force Now and for the Future!
MikeKE0ZUinkcmo
Member

Offline Offline

Posts: 340



« Reply #1 on: March 11, 2019, 07:36:14 AM »

Thank you for the link Tom.  Quick, interesting read.
Logged

Mike KE0ZU

Bold Text and PICS are usually links

https://mikeharrison.smugmug.com/
PA0NVD
Member

Offline Offline

Posts: 529


Nico and Chappie (Chappie is the dog...)


« Reply #2 on: March 11, 2019, 12:49:25 PM »

Very nice link Tom, thanks a lot
Here some more info of the Coherer receiver.
At the pic you see a replica of the Meiser and Mertig receiver of 1900 that I did build with the help of information and pics of the real receiver that is in a museum in the UK. They have the only one in existence of this type .
The receiver has a coherer simply made of a small glass tube (1/4 of an inch in diam.) two electrodes glued inside and filings of steel. It is advisable not to use a magnetic steel, the particles have the tendancy to stick together when magnetized . I think I used SS, but I am not sure after a few years. I didn't find much difference in sensitivity using various metals.
I made the polarized relay with an impedance of 3500 Ohms and used a battery of 1.5 Volts. The relay works with 0.8 Volts minimum at approx 250 uA. It has a rotatable magnet aside to cancel the effect of the earth magnetic field and adjust the relay at maximum sensitivity..
The receiver works already with pulses of approx. 10 uWatt and gives out 1 Watt DC at 4,5 V to drive the writer, so it has a comparable gain of 50 dB, quite amazing.
With a small spark transmitter (an original of 1900 used to sell to laboratories in 1900 to investigate the Herzian Waves), I can repeat many experiments as done by Marconi experimenting with antennas and tuning


* coherer receiver 010.jpg (111.47 KB, 780x585 - viewed 51 times.)

* spark transmitter 002.jpg (61.36 KB, 480x640 - viewed 46 times.)

* spark transmitter 003.jpg (53.42 KB, 502x477 - viewed 45 times.)
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.056 seconds with 18 queries.