Meisner and Mertig coherer receiver

ID: 372129

This article refers to the model: Coherer Receiver (Meiser & Mertig; Dresden)

Meisner and Mertig coherer receiver

22.Feb.15 13:32

204

Nicolaas van Dijk (CR)
Articles: 43
Count of Thanks: 5

A while ago I started to build a polair relais for a coherer receiver with the idea to do testing and perhaps building a complete receiver. With the help and a whole lot of information from Nikolaus Lowe (to whome I am very gratefull), I did build a relais that did switch at a voltage of approx 1 Volt and with an impedance of 2.5 kOhm (when adjusted well)

At internet I found pictures of the receiver friom Meisner and Mertig in a museum. I did contact the museum and inmedeately received pictures from which I started to build such a receiver using the relais.

The coherer has copper electrodes and RVS metal filings. Iron metal filigs worked perfectly, but were easily magnetisised wich impaired the correct functioning of the coherer.

The only thing still to be made is the wooden base, but I tested the receiver and did like to share the results.

The sensitivity is good, when you approximate the gain of such a receiver, it is amazing.

I measured the input impedance with an open coherer and a CW signal of - 30 dBm. It was in the order of 1 kOhm at 1-10 MHz. The peak RF voltage measured at the input generated by the spark of a BBQ lighter was approx 100 mV. at the threshold where the coherer detects.

That means that the detected input power was approx 10 uW.

I could easily swith a 1 Watt load at the output resulting in an approximated gain of 50 dB!!!!

In order to get a reliable decoheracion (is that correct English or did I invent a new word?), the coherer has to be attached a little sloppy. When attached firmly, the decoherer sometimes does not function and ticks twice.

It is really fun to experiment with coherers, highly recomended!!.

Kind regards

Nico

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Meiser and Mertig receiver is finished

06.Mar.15 17:48

204 from 1925

Nicolaas van Dijk (CR)
Articles: 43
Count of Thanks: 5

The receiver is finished and working very fine. Attched a few pics.

Kind regards to all.

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