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*COMPLETED* simple S meter? for a minerva tropic master
#1
Tongue 

maybe i need to do sum searchin eh before i post?   
Naw,, me thinks ill be a brat Icon_smile

I have me a minerva tropic master and armed with some notes i took from a member about how to hand make a BFO , i jumped in.
i quickly realized i dont like my note taking , so i move over to exploring a S Meter mod to this set.

although i know there is a few generation gaps for me to catch up with to get better at working on this tech, i am trying real hard.  My RF skills are all be zilch,  i mean i understand how all this RF stuff operates, i just dont have the experience to understand how it works if that makes sense.  its just like mux / dmux digital tech but on an analog form with all kinds of parts on either end specific to RF.  Ive never had a job where RF was something i visited often enough to end up needing to "know it" well.


when things like this happen to me, i tend to adapt in different solutions that involve using techniques i already know.

Adding an Smeter to my minerva was explored for a few hours last night.
i went in thinking about what i know.
i know :
--that when we tune , signals become stronger or weaker.
--RF signals with respect to the reference IF are being detected, and amplified, passed on down to the speaker.
--the speaker is nothing more than a wound up coil of wire and or an integrated magnet reacting to the signal that was previously amplified.
--there must be a few terminations that are constantly changing in voltage with respect to the peak to peak amplitude of the signal being compared to the IF.
-- i know that as you turn the tuner knob voltages must change.
--an smeter could be described in a basic conversation as nothing more than a meter bridged across a shunt tow which the shunt is constantly bombarded with varying really super low voltage like mili volts.


at this point i have found in the minerva at least six terminals that vary in voltage.
I also found that at my speaker, the mv readings are monitorable.  ive noticed that with the volume set to a reasonable level, for this set it seems that around 20mv means "nothing is there".  When there is  a station, the mv reading could be around 50mv on a weak signal to as much as 500mv on a strong one.
i took my readings with both a analog meter and a digital one and the act of inserting the meters across the speaker had affect on signal reception or audibility.  this got me to thinking................ of something i already know i can do to build a decent Smeter.

I want to tie a millivolt meter across the speaker as a visual indicator of signal strength.


a few links i am using as the "style" i would like.
this must be small
must be a millivolt meter 0-500mv or 0-500-0 etc


this one goes only to 100mv,, i know that strong stations and depending on my vol knob,, it would max out and peg most of the time.
https://www.ebay.com/itm/0-100MV-2A-MILL...Swxu5ZJAvn


is there a place i can buy a analog millivolt meter with a wider measurment range?

should i just buy a 10$ cheapy analog meter and gut it and re-box it and make my own by setting it to the proper scale then mount and call it good.?





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