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Sunnyvale, CA | Use right angle TNC connectors with 50 ohm cable, type RG58-CU. The RG59 and RG-6 cables are 75 ohm cables, usually with F connectors and a solid center conductor. The center conductor of the RG58-C cable is stranded and twisted and resists breaking from flexing. the solid center cables are quite susceptable to breaking on a tarctor because flexing solid copper conductors causes work hardening brittle fractures to occur.
we have seen some cheap import TNC connectors with slightly over-sized center pins that tend to destroy the center pin contact on the EZ-Guide and antenna TNC connector, so make sure the center pin is within spec, because it will cost a lot more than the price of a cable if you have to send your EZ-Guide 500 to have the connector replaced because you used a mis-sized center pin.
It is also important to make sure water does not seep in between the shield and center insulator at the connector. If water does get into the cable, the cable will exhibit excess loss and the SV SNRs will be low on the status screen. When not in use, make sure the open connector left on the roof is not exposed to the rain. Good TNC connectors have o-rings and tend to be resistant to rain when seated and the ends should be covered when not in use.
Low cost cables tend to have less % braid and these coax cables leak a little. The leakage can cause the antenna to oscillate if the leakage gets back into the antenna element. You can tell if the antenna is oscillating caused bya leaky cable because the GPS will not be able to track any satellites. Making sure the cable leads directly away from the antenna is helpful in preventing feedback from a leaky cable.
Most cheap cables are not right angle and the cable bends at the crimp ferrule. After enough bending, the connector breaks or the braid becomes an open circuit, hopefully when it is convenient to change out the broken cable, and not in the middle of planting, while trying to beat the rain.
other than these potential problems, cheap cables can work great. | |
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EZ 500 antenna cable
