length of coax

22 links

Vertical antenna for 20-15-10 m - This is a vertical multiband antenna made up of several aerial elements lambda/4 length, feeded with just a coaxial cable in French.
[ Hits: 23571 | Votes: 20 | Rating: 5.2 ]

Squarooka Antenna - squared bazooka for 2 meters band - Sort of similar to the one of the 6m omni. Instead of using twin-lead, this design makes use of a more or less regular double bazooka antenna (coaxial dipole). Your attention shall be drawn to the available standart literature, such as Rothammel. In order to "compute" the dimension, Karl Rothammel mentioned that the total length of the dipole shall be 95% of the free-space wavelength. The short-circuit bridges (closing the folded dipole) are to be placed at a distance-fraction being equal to the velocity factor of the coax cable used, which will be 66% using RG-58 or RG174.
[ Hits: 356 | Votes: 0 | Rating: 0 ]
Lightweight 144 MHz Yagi antenna - A Lightweight 2m Yagi for SOTA. The boom is 20mm PVC electrical conduit and the elements are 2.4mm aluminium TIG welding rod. The antenna is carried as a single length of conduit with the elements stowed inside the boom, sealing them in with a bung. The driven element is connected directly to 50 Ohm coax with a BN-43-202 balun core to decouple the coax shield.
[ Hits: 178 | Votes: 0 | Rating: 0 ]

40m loaded dipole - This is an short dipole for 7 MHz. Total length of this dipole is just 10 meters, 33 feet. Missing lenght is balanced by a coil made of 49 turns of a 40mm diameter pvc pipe. The use of a choke balun is recommended, as always, to adapt the unbalanced coax cable to the balanced antenna, and to prevent RF feed back along the coax shield.
[ Hits: 193 | Votes: 4 | Rating: 8.75 ]

Bazooka dipole for 70 cm band - Here is a very simple 70cms dipole from Harald PD2HFE, which uses a single piece of RG-213 coaxial cable 34 cms in length.
[ Hits: 16562 | Votes: 30 | Rating: 6.67 ]

A Cost Effective Current-mode 1:1 Balun - A cost effective current-mode 1:1 balun can be constructed from a length of coax and a rod typically used for a broadcast antenna loop-stick, some electrical tape, cable ties, a length of PVC water-pipe and some connectors.
[ Hits: 9193 | Votes: 4 | Rating: 7.25 ]

The Guanella 1:4 balun - A cost effective current-mode 1:4 balun can be constructed from two lengths of coax, two ferrite rods, some electrical tape, cable ties, a length of PVC water-pipe and some connectors. This form of 1:4 current-mode balun is named after G. Guanella.
[ Hits: 3636 | Votes: 1 | Rating: 10 ]

Coax Dipole Calculator - An efficient program to calculate dimensions of coax dipoles, or bazooka antennas considering velocity length of different coax cables. Express dimensions in feet/inch and meters/cm. Freeware by VE3SQB
[ Hits: 17578 | Votes: 74 | Rating: 5.31 ]

Coaxial antennas - G3TXQ study on coaxial cable demonstrate that it can reduce an element's length by something approaching the Velocity Factor of the cable
[ Hits: 1290 | Votes: 1 | Rating: 10 ]

Full Wave Loop Dimensions - This article contains the measurements for building a full wave loop using wire and length of 1/4 Wave Coax Matching Transformer
[ Hits: 1088 | Votes: 3 | Rating: 7 ]

Simple Coax Mag Loop Antenna - A homemade Magnetic Loop antenna from a spare 3m length of RG213 working from 30m to 15m with a 130pF tuning capacitor
[ Hits: 4001 | Votes: 11 | Rating: 7.18 ]

Archimedean Spiral Antenna for RTLSDR - Dodgy plans to make Archimedean spiral antenna for RTLSDR software defined radio receiver. Made of two equal lengths of coaxial cable seems to be the easiest circularly polarized antenna to make that will cover a broad range of the rtlsdr dongles E4000 tuners
[ Hits: 1033 | Votes: 2 | Rating: 10 ]

Quarter Waves and Velocity Factor - Coax Velocity Factor in Baluns, Does it Matter? Test results show coaxial cable velocity factor does not always enter into stub length calculations especially in the world of Baluns
[ Hits: 208 | Votes: 0 | Rating: 0 ]

CoaxTrap - This program let you design of antenna trap using length of coaxial line wound as solenoid on a coil former.
[ Hits: 5524 | Votes: 10 | Rating: 3.7 ]
Bootstrap coax traps for antennas - Analysis of an antenna trap where a coil is formed of a length of coax cable, the outer conductor of one coax end is tied to the inner conductor of the other coax end, and the remaining connections form the terminals for the trap.
[ Hits: 1356 | Votes: 2 | Rating: 9 ]

Windom Antenna with 4:1 balun - The Windom is an Off-center wire multiband Antenna. The old version was fed just by a single-wire connected on 1/3 of antenna's overall length or with an open-line feeder (later versions). Here is another model with coaxial feeder, which is compatible with Solid States - 50 Ohm output transceivers .
[ Hits: 8027 | Votes: 9 | Rating: 6.89 ]

Revisiting the GR5V and ZS6BKW Multi-band Antennas - NEC models are used to explore the GR5V and ZS8BKW optimizations. A third optimization is also rediscovered. The effect of fixed lengths of 75 ohm coax are explored. A link to the NEC model is provided.
[ Hits: 312 | Votes: 1 | Rating: 10 ]

Coaxial Cable & Power Handling - This calculator can be used to estimate the attenuation (dB loss), power handling capability, and transmission efficiency for some of the more popular Wireless Communications and MIL Spec cables at the frequency of interest
[ Hits: 1183 | Votes: 8 | Rating: 8.17 ]

Measure Impedence of Coax Cables - This video shows one way to use a scope and function generator to measure the length of a piece of coax transmission line as well as estimate its impedance
[ Hits: 1093 | Votes: 3 | Rating: 6.67 ]

miniVNA PRO Modifications - The mini Radio Solutions miniVNA PRO is the only affordable vector network analyser (VNA) I know of that offers remote wireless operation. This is very interesting because it allows to measure the input impedance of HF antennas installed at height without having to deal with coax cable lengths, baluns nor common mode suppression chokes. However, to render the miniVNA PRO truly field proof, it requires a number of significant modifications.
[ Hits: 136 | Votes: 5 | Rating: 7.8 ]