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#1
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F.S. National Comapny S meter
sparky wrote:
National company signal strength meter used in some HROs and other National radios. price is $25.00 plus shipping. a href="http://s820.photobucket.com/albums/zz123/sparky12x/? action=view¤t=DSCF0011.jpg" target="_blank"img src="http:// i820.photobucket.com/albums/zz123/sparky12x/DSCF0011.jpg" border="0" alt="National Meter 2"/a Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? |
#2
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F.S. National Comapny S meter
Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. |
#3
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F.S. National Comapny S meter
sparky wrote:
Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. |
#4
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F.S. National Comapny S meter
See this picture HR)-60
http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39*pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. * The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. *Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. |
#5
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F.S. National Comapny S meter
sparky wrote:
See this picture HR)-60 http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39 pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. I guess the meter will drift to the right when power is applied to the radio with no signal. Weird. I'm going to have to find the schematic to the HRO and figure it out. |
#6
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F.S. National Comapny S meter
Kenneth Scharf wrote:
sparky wrote: See this picture HR)-60 http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39 pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. I guess the meter will drift to the right when power is applied to the radio with no signal. Weird. I'm going to have to find the schematic to the HRO and figure it out. I meant drift to the LEFT when power is applied. |
#7
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F.S. National Comapny S meter
"sparky" schreef in bericht ... See this picture HR)-60 http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39 pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. The AR88 had also a meter with the zero left (when there was a meter anyway, because many had no meter at all) It measured the cathode current of one of the IF tubes. (Less amplification/cathode current means more signal). That leads to the somewhat odd 'zero right' configuration MRe PE1NQr |
#8
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F.S. National Comapny S meter
I found the schematic for an early HRO
(http://www.portabletubes.co.uk/sitefiles/hro1259.djvu), it seems the s meter is in series with the plate circuit of the last IF stage, so it measures the plate current. At maximum signal the plate current of that stage must be close to zero to send the meter to the 60 over nine position. MRe wrote: "sparky" schreef in bericht ... See this picture HR)-60 http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39 pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. The AR88 had also a meter with the zero left (when there was a meter anyway, because many had no meter at all) It measured the cathode current of one of the IF tubes. (Less amplification/cathode current means more signal). That leads to the somewhat odd 'zero right' configuration MRe PE1NQr |
#9
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F.S. National Comapny S meter
On Dec 22, 8:26*pm, "MRe" wrote:
"sparky" schreef in ... See this picture *HR)-60 http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39 pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. The AR88 had also a meter with the zero left (when there was a meter anyway, because many had no meter at all) It measured the cathode current of one of the IF tubes. (Less amplification/cathode current means more signal). That leads to the somewhat odd 'zero right' configuration MRe PE1NQr- Hide quoted text - - Show quoted text - Not sure one can understand the dilemma! Lets say the meter is typically in the plate circuit of one or several RF or IF amplifying tubes. When the set is active and with no signal, the meter deflects (from right to left). That type of meter is often called a 'Right zero' meter). When a signal is received a negative AVC voltage is generated; applied to the grid circuits of the amplifying tubes their plate current is reduced. The stronger the signal the greater the AVC voltage and ergo the greater the reduction in plate current. Hence the meter swings towards the right (or zero) in proportion to the strength of the received signal. |
#10
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F.S. National Comapny S meter
terryS wrote:
On Dec 22, 8:26 pm, "MRe" wrote: "sparky" schreef in ... See this picture HR)-60 http://www.universal-radio.com/CATAL...xvr/HRO60.html it has a meter with the zero on the left. On Dec 21, 7:39 pm, Kenneth Scharf wrote: sparky wrote: Why is the meter 'zeroed' against the right peg, is it broken? Or did National design it that way because they had a backwards meter circuit that pulled full current with zero signal? This is a backward meter by National. The meter deflects left when current flows. The radio must have had a backwards meter amplifier then. Weird. Guess one could design a proper solid state amplifier to make it work, but you'd have to 'zero' the meter at full scale with no signal. The AR88 had also a meter with the zero left (when there was a meter anyway, because many had no meter at all) It measured the cathode current of one of the IF tubes. (Less amplification/cathode current means more signal). That leads to the somewhat odd 'zero right' configuration MRe PE1NQr- Hide quoted text - - Show quoted text - Not sure one can understand the dilemma! Lets say the meter is typically in the plate circuit of one or several RF or IF amplifying tubes. When the set is active and with no signal, the meter deflects (from right to left). That type of meter is often called a 'Right zero' meter). When a signal is received a negative AVC voltage is generated; applied to the grid circuits of the amplifying tubes their plate current is reduced. The stronger the signal the greater the AVC voltage and ergo the greater the reduction in plate current. Hence the meter swings towards the right (or zero) in proportion to the strength of the received signal. If you need a replacement S meter for an HRO or any receiver that used this kind of S meter circuit, fine. When I saw that S meter I thought it would look 'cool' in a (solid state) QRP rig I was planning. But, I'd have to come up with a 'bass-ackwards' meter circuit to make it work. I suppose that the meter should end up in another HRO or similar receiver that needs a replacement though. |
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