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Cobra 29 modulation adjustment.

Terry Thornsberry

New Member
Oct 13, 2016
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Ohio
I have a somewhat newer 29 ltd classic, 2011 model. Every post I've read about the modulation adjustment tells you to turn vr4 all the way up counter clockwise, problem is my radio has no VR4. Is RT4 the same as VR4 ? Any answers greatly appreciated.
 

My money is on "he gets on Loud", without an o'scope he may never know just what he has done.
Anything turned up past stock on a 29 wont look good on a scope. Some of the few that I have looked at, look really bad! Being stock and fairly narrow banded and getting a little wider with harmonic distortion doesn't hurt anyone.

I might have to check that out one day, if you crank the mod on a 25/29 how much wider will it make your signal? I have a couple radios I could try this on.....
 
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Edit: A video is coming soon (Within 24 hours) with flashy waterfall(s)!!!
But I don't think it going to get very wide even with a clipped limiter, a ceramic filter is inline for TX and RX, correct?


Boy I bet I could really generate some harmonics with "talkback" and his cousin "Mike Gain" while creating a nasty feedback loop!
But even with a clipped limiter and the stock mic audio in my mind it's not going get "too" wide, even though it will splatter and bleed because of all the harmonic distortion "bouncing around" when the radio gets slap-retarded on RF spectrum, because of negative peaks and audio distortion it produces nasty crud all around your target frequency ultimately wasting energy and efficiency of the transceiver (for what the sane, & normal people like me want to do with a radio). I will have to test to confirm.


Let's say you have an export & a computer to direct inject it, and you've already done a true, clean and proper asymmetrical modulation modification (Add some processing through the computer) That Mid/Hi-Fi signal is going to look wider, no doubt about that in my mind, and it will sound great I believe I just have to hook an export radio I have to a Dummy Load and I will import the captured audio from the RTL-SDR into the video with Windows Home Movie Maker or w/e I find.

" 73, LeapFrog going 10-6 "
 
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I looked at a Cobra 29 with a clipped limiter, and without on the SDR waterfall.
It got into the adjacent channels, & audio gain(not really bandwidth) increased but not by anything to right home about with the clipped amc, it sounded distorted
(& "very loud").

I may one day shoot a video, my description is incomplete and not 100% accurate.
 
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Yes with the 54 mhz trap circuit intact, the 2nd harmonic was -60db down this changed hardly (if at all) with the limiter clipped, this was my first time using an SDR, keep in mind I may have no clue what i'm talking about after all!
 

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