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  1. Q

    Impedance Matching Hairpin/Coil?

    I'm making a 5/8 wave vertical antenna. I understand that inductance matching with a coil lowers the impedance of a 5/8 wave that I believe is about 250 Ohms. Is the coil design using its magnetic field to create inductance as its main purpose? Or is the coil just using its length to...
  2. Q

    Cobra 148 IC3 pin 7 voltage

    My Cobra 148 GTL (Philippines), IC3 (AN612) pin 7 is showing 7.6 volts. I'm trying to do an alignment and checked for voltage before connecting my BK 1803D freq counter. The max input for the counter is 3 volts. I thought that pin should be 2.8 volts? I did notice R131 was cut, so I put a new...
  3. Q

    PC-122 Bias Adjustment/Transistors

    Does anyone know the what the PC-122 bias adjustments should be set to? I do not have a service manual. I noticed the similar radios like the TRC-453 and Uniden 810 have different values. Where is a good source for authentic 2SC2312C and 2SC2166 transistors? Thanks.
  4. Q

    Transmit Frequency Potentiometer

    I have a question about adjusting the transmit frequency for a Cobra 148 and Realistic TRC-451. My radios were off frequency, so I adjusted the transmit frequency potentiometer in each radio. For example VR3 in the Realistic. I only have a 5 digit frequency counter, and used that while...
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