![]() ◄- Repair Membrane Buttons - NVIS Antennas -► ![]() Transmission Line Loss technical tutorial from Note: Set Line Length 100 here to use the ERP Calc. Note: the RG numbers given are not actual labels, but are given merely for familiarity. How much attenuation is acceptable? Well, a mere 3dB will waste 50% of your wattage!Ĭlick the links below for manufacturers’ data-sheets. ![]() Though frequently ignored, all RF transmission lines have maximum RMS voltage, and maximum power (wattage), which varies with type, brand, and frequency.Windowed ladder-line (WLL) should be (1) kept at least a few inches from metal (to prevent magnetic induction losses) (2) twisted 1/2 turn per foot (to prevent wind flap) and (3) turned at a large radius (12 inches or more).All foam-type coax cables should be taped- not attached with plastic cable ties or wire-to tower legs, etc., to prevent deforming of the foam dielectric.There are at least four commonly-used types of coax dielectric: (1) semi-solid polyethylene (PE) for temps up to 80☌ (V p 66%) (2) gas-injected PE (foam PE) for temps up to 100☌ (V p ~85%) (3) air-core: a thinner PE with a PE strand spiraled around the inner conductor (V p ~85%) and (4) PTFE (Teflon) for temps up to 250☌.However, stranded center conductors have a little higher loss than solid ones. The flexible types (9913F and LMR-400UF) are preferred, particularly for rotatable antennas. Suitable for VHF (~1.5dB loss per 100 feet at 146 MHz). 9913 and LMR-400 are popular “low-loss” RG-8 types.Suitable for higher power (~1800 watts) at HF. Suitable for medium power (~350 watts), HF and Lo-VHF. RG-8X (50 ohm) and and RG-59 (75 ohm) are about 0.24 inch.RG-6 (75 ohms) is about 0.332", typically used for cable/satellite TV.RG-58 (50 ohm) is about 0.195", quite lossy, suitable only for mobile installations (typically Suitable only for short pigtails and jumpers at very low power, as in receivers, scanners, etc. Please don’t ask me to add another coax! I don’t know where or how the K1 and K2 constants used in the arrays were obtained or derived. Always look up the cable manufacturers’ specifications and installation guides for any RF cable prior to purchase and use. This program is provided “AS-IS.” It is the responsibility of the user to verify the accuracy of the calculations when using this program. For more info, please see this AC6LA page. He later withdrew the code in favor of more accurate formulae. The Javascript that runs the loss calculator was written in 2001 by Dan Maguire, AC6LA, based on ARRL's "Additional Loss Due to SWR" formula. RF Feedline (Coax and Ladder-Line) Loss and ERP Calculators About Dough Types, Procedures, and Properties.How to Become an Amateur Radio Operator.706: Computer Control and Soundcard Interface.Amateur Radio Frequency Allocations and Band Plans.
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