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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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29th Nov 2009, 6:51 pm | #1 |
Rest in Peace
Join Date: Nov 2006
Location: Leominster, Herefordshire
Posts: 174
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"S" Meter on CR100/B28 Series
Hi Forum,
Does anybody have any info on the above mod? Any info gratefully received, and any hints. (Even, don't be so stupid!!!) Mike Bayliff M0XGG |
29th Nov 2009, 7:27 pm | #2 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,510
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Re: "S" Meter on CR100/B28 Series
Mike,
Please don't go and mash a hole in the front panel for a meter as was the thing to do at one time. There must be twenty CR100s with modified front panels survive for every one unmodified! Andy |
29th Nov 2009, 7:51 pm | #3 |
Heptode
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 595
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Re: "S" Meter on CR100/B28 Series
Hi Mike
Agree with Andy, but if there's already a hole use it ! A better idea is to fit the meter in the speaker housing. Attached is the circuit I used. Almost any N channel FET will do, the circuit being driven by the AGC line. Received signals give a forward reading on the meter, after the 500 ohm pot is used to 'zero' it under no-signal conditions. Regards Pete |
29th Nov 2009, 8:05 pm | #4 |
Rest in Peace
Join Date: Nov 2006
Location: Leominster, Herefordshire
Posts: 174
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Re: "S" Meter on CR100/B28 Series
I agree with both of you, Andy and Pete, no new holes should be drilled. Mine will probably be external mounted, my pal has one that has been butchered by chrome plating the front panel!
Anyway, many thanks, Pete, for the circuit. |
1st Dec 2009, 8:47 pm | #5 |
Rest in Peace
Join Date: Nov 2006
Location: Leominster, Herefordshire
Posts: 174
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Re: "S" Meter on CR100/B28 Series
Mods, you can close this thread if you like
Mikebay |
1st Dec 2009, 8:54 pm | #6 |
Dekatron
Join Date: Feb 2005
Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW
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Re: "S" Meter on CR100/B28 Series
Pete, that is a very elegant solution, I like it!
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Engineers make things work and have spare bits when finished |
1st Dec 2009, 10:02 pm | #7 |
Heptode
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 595
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Re: "S" Meter on CR100/B28 Series
I can't claim ownership of the idea behind the circuit Sean.
I tried a few different s-meter amp circuits, but the one I submitted seemed to give the best results for me. Also, I'd mention that one of my CR100s had 3 in diam. hole in the panel for a meter when I got it. This I filled by screwing a sheet of aliminium behind it, then leveling the front appperature with decorators' filller. After sanding & spraying, the result is quite convincing ! Regards to all on this great forum Pete |