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Cobra 148 GTL

The mike amp has its own filter cap on the power for that circuit. It's C18, originally 47uf. Got in the habit of using 470 or 220uf to replace it. Usually clears up this issue.

73
Great advice, that cleared it up!
On another note, what is the best Unlocking Clarifier Mod out there with the least amount of slide, Im not crazy about trying to tune in on sideband with a clarifier that go a channel plus. I remember reading out here somewhere of a mod that gives you 5-6 each way. Are you aware of a good mod for the cobra 148 that would do that.

Regards
 
C148 Clarifier mod.jpg

PLL +8v - anywhere along that trace from R137 to the jumper (JP53 ?? can't read) that connects to the trace under the PLL should be good for +8v constant.
R175 is a 3.3k. Increase this value, this decreases the amount of slide. Lowering it from 3.3k increases the amount of slide. You could also add a resistor in series with the "top" of the RIT/Voice Lock/Clarifier pot, the end that goes to the +8v source. The lesser variance in voltage that the Clarifier pot has from top to bottom, the lesser the amount of slide. You will have to realign the PLL adjustments (the 33 MHz PLL loop adjustments) to get back to center slot. If you want the amount of slide to be more "linear", equal amounts of rotation = equal amounts of slide, make sure to put R44 and R174 back in.
 


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  • @ Geoexplorer69:
    Coax question. I just put up a new Sirio monsoon base antenna with 100’ of rg8u coax testing with myMFJ antenna analyzer shows 1.4 swr at 26.965mhz and a 1.1 at 27.405 mhz . When I checked the ohms it’s steady a 30 ohms across the entire bandwidth.
  • @ Geoexplorer69:
    Is 30 ohms worth worrying about in a 100’ run of rg8u ?


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