Motorola Micor VHF Channel Element

[rescuecomm]

Roughly how far will the transmit channel adjust from the crystal frequency. Plus or minus 5 kHz? It's on 145.110 mhz, but the problem is when I built the wide split repeater in 1994, I put the receiver on 147.600 which is the up input of the local 146.400/147.000 repeater. The offset is 2.49 mhz which was okay back in the day, but now most handhelds want odd offsets to be be 50 kHz steps unless using a computer. It will be easier if the repeater transmit frequency was 145.100 mhz. Will it go there? This repeater was to be used as as temporary portable unit covering a triathlon at a rural state park. The event was canceled after a 4 year run and now is pretty much a curiosity.

 

[wgbecks]

It's been a very longtime since I last adjusted a Micor channel element but I am pretty sure that you won't be able to pull it that far from the original frequency. However, If you open up the channel element you should be able to solder a small value silver mica capacitor across the trimmer to increase the capacitance enough to pull it down in frequency but you'll have to experiment with the exact value to achieved the
desired result leaving enough adjustment in the trimmer to perform maintenance adjustments over time.

 

[ramal121]

You maybe will be able to swing 2 kHz on either side of center. You can try adding a cap but be aware it will affect the IDC setting. The larger the value the less adjustment you'll get from the pot.

 

[rescuecomm]

Thanks for the feedback. The radio has been in storage so long, it might not work anyway. The last backcountry communication test was done using a Yaseu dual band radio in cross band mode with a deep cycle battery. It worked very well except for the failure to train the guys who showed up.. Any future ops will probably use my old Kenwood TM-V7A in an ammo can.