M0NTV video on SSM2167 microphone module
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source: https://www.youtube.com/watch?v=Aclr229Kq5c
Nick ("the Vic") mentioned that all the little red SSM2167 modules he has bought have resistors R1 and R2 swapped. I checked the one I bought in 2019 and can verify Nick is right, R2 is 1K ohm, should be 15K ohms, R1 is 15K ohms, should be 1K ohm. As Nick did, I'll try removing them and replacing with through hole equivalents.
He also mentioned his DVM, a Brymen BM235. Touted by EEVblog but well over $100 - I think I'll wait until the Metex finally bites the dust :)
Good video, I will have to start looking at Nick's older videos as well.
BTW, just for the heck of it I tried my unmodified module listening to W1AW code practice on 80 meters with the K2 as the receiver. The idea is to see how fast the limiting /agc is. Here are scope pictures of the leading and trailing edges of a code element with the input in yellow on top and the output from the SSM2167 on the bottom in blue:
As can be seen that while the limiting is immediate, it takes quite a few cycles at the leading edge of the element before the AGC tames the square wave back to a sine wave. Oh well, just a thought that it might be useful in a non-agc rig to save the operators ears without distortion. Possibly the module could be modified to increase the AGC speed ?
Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm
source: https://www.youtube.com/watch?v=Aclr229Kq5c
Nick ("the Vic") mentioned that all the little red SSM2167 modules he has bought have resistors R1 and R2 swapped. I checked the one I bought in 2019 and can verify Nick is right, R2 is 1K ohm, should be 15K ohms, R1 is 15K ohms, should be 1K ohm. As Nick did, I'll try removing them and replacing with through hole equivalents.
He also mentioned his DVM, a Brymen BM235. Touted by EEVblog but well over $100 - I think I'll wait until the Metex finally bites the dust :)
Good video, I will have to start looking at Nick's older videos as well.
BTW, just for the heck of it I tried my unmodified module listening to W1AW code practice on 80 meters with the K2 as the receiver. The idea is to see how fast the limiting /agc is. Here are scope pictures of the leading and trailing edges of a code element with the input in yellow on top and the output from the SSM2167 on the bottom in blue:
As can be seen that while the limiting is immediate, it takes quite a few cycles at the leading edge of the element before the AGC tames the square wave back to a sine wave. Oh well, just a thought that it might be useful in a non-agc rig to save the operators ears without distortion. Possibly the module could be modified to increase the AGC speed ?
Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm
