Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[bdanger]

My VR36A has a broken off antenna. I re-soldered the coaxial cable back on the patch antenna, but reception is lousy now. My question is how long should the coaxial cable be exactly? I think a small piece of the shielding is missing. I understand from other mod pages that the original coaxial cable should not be shortened. I need the measurement from the PCB to the end of the coaxial cable. Any one know the original length? Can the length really effect the reception?

[dave w]

Slightly shortened coax between the VR36 antenna and the receiver circuitry should not have any effect on the VR36 range.

Recheck your connections and soldering. Look for a strand of the shield touching the center conductor. I don't know if the center conductor insulation is teflon, or foam, but if foam, make sure the foam isn't melted. Also you might try checking center conductor to shield with an ohm meter. It should read fairly high.

[bdanger]

I checked the opposite sides of the patch antenna with a ohm meter on 200k setting, there is no resistance, 00.0 like a dead short. Probably melted the inner insulation when soldering? Could the circuit itself show the same reading?  So the two sides should show some resistance? If so how much? Thanks Dave for the advice.

[dave w]

I checked the opposite sides of the patch antenna with a ohm meter on 200k setting, there is no resistance, 00.0 like a dead short. Probably melted the inner insulation when soldering? Could the circuit itself show the same reading?  So the two sides should show some resistance? If so how much? Thanks Dave for the advice.

Yes, you have a shorted coax.

Should definately not be zero. I don't know what it should be, but the input resistance of a receiver should be high when you ohm across the input (center lead of coax to shield) on the 200K scale. I would think even up in the megohms as normal for receiver input(?).

[bdanger]

I disconnected the patch antenna and measured for continuity again, checking just the coaxial cable. Again no resistance, dead short. Maybe the unit has a bad capacitor. I'll make more tests later. Thanks Dave.