One conversation topic seldom spoken of is feed line loss and its influence on antenna performance. It wasn't until reading about Micro dB Theory and its dearth of available literature that I decided to seriously drill into the topic.
The premise of micro iterations both inside and outside the shack relating to improving one's RadioSport score is definitely measurable. Additionally, by investigating our literature, I can parse fact from fiction and establish a workable framework to begin testing and executing against.
For that, I'm grateful to those whom lead the way, and continue leading, because this is a crucible moment for Amateur Radio's portfolio of programs and general public interest in those programs.
What is feed line loss? I pulled out my trusty Extra Class License Manual, Ninth Edition published by the American Radio Relay League (2011) whom Ward Silver, N0AX authored for an authoritative beginning at learning about the physical connection between antenna and transceiver.
Likewise, I wanted to account for Brian Kassel's quick decibel calculation in his "Decibels, a Refresher" in the September/October 2002, Volume 30, Number 5 issue of the National Contest Journal.
Kassel suggested one must account for system debits in addition to calculating gain as measured in decibels (2002). One debit to consider is feed line loss.
Basically, Silver (2011) suggested that feed line loss is a function of increasing one's operating frequency including the choice of the dielectric material inside the coaxial cable. Admittedly, I never considered the material component as influencing line loss, and Silver explained it in journeyman terms.
My inner engineer understands the difference between PE (solid polyethylene) and FPE (foamed polyethylene) as explained by Silver. The author suggested additional air pockets inside coaxial foam reduced loss and increased velocity factor (2011). However, according to Silver, where a system credit exists there follows a system debit; decreasing feed line loss and improving velocity factor lowers high voltage capability of coaxial lines.
Please reference Table 9-1, on page 9-32, in the Extra Class License Manual, Ninth Edition (2011) and take note of transmission line characteristics. I soon discovered 'why' elite stations prefer aluminum jacketed hard line for runs greater than 100 feet and its root mean squared voltage characteristics. Likewise, the resilient parallel line and its dB/100 foot low loss and high voltage capabilties, over that of commonly used transmission line.
Life is high frequency.