Tuesday, July 05, 2016

Trouble shooting tips for the YCCC array

Did you check each of the 9 preamps? Disconnect all of the antenna feedlines from the combiner and reconnect each one to the CTR port, one at a time, and power up the system. (Leave the 2 delay lines connected). Note the signal level with the one antenna connected, using a local BCB station if you can tune there. Remove the feedline when you finish testing one preamp and then repeat the same test on the next antenna preamp. They should all have the same signal level. If one is down, you have another bad preamp. Next thing to check is the 9 RF chokes on the combiner board. These are fragile devices that can fail under excessive current. With DC power removed from the system, put an ohmmeter across each of the chokes. You should see 6 ohms +/-1 ohm. If you see an open circuit or a short circuit (close to zero ohms), you have a failed choke. Finally, in the switch box unit, test the RF choke in there with the ohmmeter. Also test each of the 12 diodes with an ohmmeter. Measure the resistance across each diode with the ohmmeter leads connected one way and then reversed. One of the ohmmeter connections should show much higher resistance than the other way. If it doesn’t you have a failed diode. Do you use your array in the summer? I disconnect all cables and feedlines from mine for the duration of the summer to avoid lightning damage. I learned this the hard way. Of course, it means I don’t operate 160 or 80 in the summer, so that’s the downside.

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