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RR145/S (RR145/S)

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Forum » Valves / tubes - Semiconductors » VALVES/TUBES / SEMICONDUCTORS in RADIOMUSEUM » RR145/S (RR145/S)
           
Eero Ukkola
Eero Ukkola
 
FIN  Articles: 5
Schem.: 1
Pict.: 460
20.Apr.06 19:18

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Reply  |  You aren't logged in. (Guest)   1 Hello Friends
I found that "TUNING INDICATOR"-tube my basket. Now I thinking how methode this tube works and when it wos made and where. Its base are three letter DGL. Who knows?
BG: Eero Ukkola/FIN
Konrad Birkner † 12.08.2014
Konrad Birkner † 12.08.2014
Officer
D  Articles: 2334
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20.Apr.06 20:25

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Reply  |  You aren't logged in. (Guest)   2 All I know: it is a glow discharge device. The indicating glow area ist proportional to the discharge current.
The usual application was in the early 1930's to feed it via a series resistor from the anode or the screen grid of the AGC RF tube. Strong signal made higher negative AGC voltage, thus reducing the gain of the RF (variable mu) tube, which in turn increased the anode/screen grid voltage and simultaneously gave a higher indication on the tuning indicator. The series resistor was usually adjustable (100 kOhm pot.) and an additional electrode  (>200 v fed through 1-2 MOhm) kept a minimum discharge when no signal was there and the RF tube at full gain i.e. at minimum anode voltage.
As an example have a look to the schematic of this Radio http://www.radiomuseum.org/r/saba_weltsuper_630wl.html

This article was edited 20.Apr.06 20:29 by Konrad Birkner † 12.08.2014 .

Heribert Jung
 
Editor
D  Articles: 916
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23.Apr.06 04:52

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Here is a picture of the indicator:

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Jose Vigil
Jose Vigil
 
RA  Articles: 62
Schem.: 43
Pict.: 75
11.Jul.06 00:59

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Reply  |  You aren't logged in. (Guest)   4 Hello Eero: It is also used in the Koerting Transmare 38.
The neon discharge is proportional to the signal strenght as mention in other reply.
The effect of this indicator is great. Let me know if you want Photos of this working.
I wonder why was no longer used. Perhaps the cost.

Best Regards. Jose
  
rmXorg