Cables for the new K9ZW Home QTH

With all the underground’ conduits installed it was time to get the cables ordered.

After extensive online searching, I returned to working with DavisRF, working directly with their founder Steve K1PEK.  Steve K1PEK is a US Army veteran with an Elint/Sigint background in West Germany.

He also helped me by doing some performance vs cost comparisons of options.

The shack bulkhead to Skyneedle bulkhead is a 210 ft run, and the run from the shack to the Flagpole vertical is 250 ft.

While power and data/control have their own conduits separated by a nominal 12 inches or more, shielding remained one of my concerns as well as signal loss.

I settled on using RFS Cable Wave 1/2” product bulkhead to bulkhead and Belden 9913F7 up the tower and for jumpers.

The loss is less by significant amount across the bands, especially 17 to 10-Meters where at 10-Meters it calculates at a modest 6% loss compared to a calculated heavy 43% loss for an LMR-400 spec cable.

Steve K1PEK’s calculations suggests that the “tails” of 9913F7 will add about a 0.5 to 1 dB loss over the equivalent length in RFS Cable Wave 1/2.”  This seems acceptable as the great loops of the RFS to accommodate the tower crank-up/down and rotator rotation would require much more length clawing some of the differential back to favor the 9913F7, and the Belden is noticeably less costly – more so when the added lengths for the RFS are factored in.

A test antenna point and underground conduit for a RBOG (reversible  beverage on ground) is also getting the RFS Cable Wave 1/2” along with two high spec 75 ohm receive-only cables for the RBOG.

DavisRF is also supplying an over-gauge rotator cable as I want to minimize the voltage drop to keep rotation speed high, and a special rotator type cable for a low voltage remote-to-shack crank-up control system.

Other than the rotator type cables, everything has been ordered terminated with high quality N-connectors for the most part.  In a few cases where I don’t want to change out the existing UHF connectors on gear the cables will have one end with similar professional grade PL-259s.  Given the oversized conduit we think we can pull the wires with connectors on them.

Only the shack to tower run is getting a spare feed line, as I decided to spend my budget on the best conductors and connectors than redundancy.  I do have enough high spec LMR-400 cable and other semi rigid cable to pull in a backup if the need appears.

All in all not a cheap buy, but a performance buy at a sweet spot of best performance while remaining affordable.  In comparing vendors DavisRF has an interesting twist where many of their products are freight allowed.  So the DavisRF price includes the delivery freight costs.  So when making a price comparison you have to account for additional freight on quotes that are not freight allowed.  I also enjoy working with a capable veteran who knows his stuff.  They are at: http://www.davisrf.com

Links to the RFS 1/2″ Cellflex Cable http://products.rfsworld.com/WebSearchECat/datasheets/pdf/cache/LCF12-50JFN.pdf and Belden 9913F7 Cable https://catalog.belden.com/techdata/EN/9913F7_techdata.pdf

73

Steve
K9ZW

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