common

218 links

Common Mode Currents on Coax - These baluns are used to attenuate the common mode current that flows on the outside of the coaxial feed line.
[ Hits: 176 | Votes: 0 | Rating: 0 ]
50:450 Ohm (9:1) Balun for vertical antennas - A page describing how to home made a custom 9:1 balun for a common portable wire antenna. The author suggest to use 4C65 or FT140-61 toroids instead of the common Amidon T200-2
[ Hits: 516 | Votes: 11 | Rating: 6.72 ]

Bazooka Antenne - A bazooka antenna design in German with dimensions for 20m and 40m band with RG174 coax cable stronger than the common RG58
[ Hits: 1270 | Votes: 3 | Rating: 4.67 ]

The End-Fed Half-Wave Antenna - Presentation - A very well done presentation about End-Fed Half-Wave antennas. This PDF document contains a summary of experiences in how to build custom EFHW antennas. Includes an interesting comparison table of UnUn configurations with recommended toroids, Wire size, turns and capacitors. An useful recap on common errors in building homebrew EFHW Ununs completes the document.
[ Hits: 406 | Votes: 3 | Rating: 8.67 ]

Magnetic Loop for the 2m band - Such kind of omnidirectional antenna gives the possibility to be QRV with horizontal polarisation, as commonly used for the CW and SSB section of the 2m band. This actual design shows a 1.3:1 bandwidth of about 150kHz, centered to 144.200MHz.
[ Hits: 573 | Votes: 1 | Rating: 10 ]

Portable wire antennas - This document describe serveral wire antennas, from the folded dipole, to the common halfwave monoband antenna for those who want to make HF portable operations in holiday.
[ Hits: 845 | Votes: 2 | Rating: 1 ]

Duracomm Power Supplies - Power Solutions for Durable Communication Systems. Founded in Sep. 1992, DuraComm Power Supplies is a worldwide recognized leader in ultra-reliable AC-to-DC switch mode power supplies commonly used in the communications industry.
[ Hits: 140 | Votes: 0 | Rating: 0 ]

Morse Code Reception - Exercise sheet - Useful exercise sheet to learn morse code reception. In A4 format PDF File, it contains groups of 5 characters commonly used while learning morse code reception.
[ Hits: 1076 | Votes: 10 | Rating: 7.9 ]

Northern California Transmitter Hunters - The Northern Calfornia Transmitter Hunters are a group of people that share a common interest in amateur radio transmitter hunting.
[ Hits: 191 | Votes: 0 | Rating: 0 ]

Ameritron AL-811 Panel Meter Lights - A solutiom for the Ameritron AL-811(H) RF power amplifier, burnt panel meter lights. A common failure with the Ameritron AL-811 and similar amplifiers is that the panel meter lights burn out prematurely. These bulbs are usually integrated into the actual panel meter. The solution for this is to provide the meter backlighting with LEDs.
[ Hits: 1184 | Votes: 2 | Rating: 5 ]

Balun_cmr Calculate common-mode impedance - This EXCEL Program Worksheet calculates the common-mode impedance of a 1:1 Guanella (current) balun which is placed at the feed point of a balanced antenna system fed via coax.
[ Hits: 404 | Votes: 1 | Rating: 10 ]

Pass Recorder - Pass Recorder is a small application that records audio from satellite passes based on tracking data it receives from the commonly used SatPC32 application
[ Hits: 186 | Votes: 0 | Rating: 0 ]

FT CALC 1.3 - Ferrite Toroidal Core HF Calculator - This EXCEL Program Worksheet calculates the safe operating conditons for a toroidal transformer operating between 1 and 50 MHz. Manufacturer data for complex permeability, magnetic dimensions, and saturation flux density must be available. Some core types which are commonly used in amateur transmission are included. The program produces limiting winding voltages for linear operation and temperature rise over the range of frequencies and power specified.
[ Hits: 283 | Votes: 1 | Rating: 2 ]

Coax Loss Calculator Online by K5VR - RF Feedline (Coax and Ladder-Line) Loss and ERP Calculators made with Javascript. This complex feddline loss calculator has already several line types paramenters for most common coaxial cables from Belden, Time LMR, Wireman and other common products. Result will give Matches loss, SWR loss, dB and Watts power loss.
[ Hits: 252 | Votes: 2 | Rating: 5 ]

Choosing the correct Ferrite - Common mode currents are those currents that flow in the same direction on a wire bundle, as opposed to the currents that flow
[ Hits: 250 | Votes: 0 | Rating: 0 ]

Cost-effective ferrite chokes and baluns - In this article the author describes some new designs of ferrite loaded chokes for suppressing unwanted common mode currents at HF applied to feed lines like choke baluns, but also in the shack, applied to various coaxial, mains and data cables
[ Hits: 864 | Votes: 5 | Rating: 6 ]

Interfacing HAM radio - An article about interfacing amateur radio devices, usually transceivers to computers. It is a general article that cover common interface models using USB or RS232 for popular ham radio brands like Yaesu Icom and Kenwood
[ Hits: 553 | Votes: 1 | Rating: 10 ]

An Experimental Q Meter - The article describes Q factor, methods of measuring Q factor, inductance and capacity using a Q meter and the design of an experimental Q meter unit. The Q factor or quality factor of an inductance is commonly expressed as the ratio of its series reactance to its series resistance.
[ Hits: 235 | Votes: 0 | Rating: 0 ]

TYT MD-390 Rx Audio Issue - Common issue on the TYT MD-390 when the speaker start sounding like it is broken, but it depends by the external mic cover.
[ Hits: 172 | Votes: 1 | Rating: 10 ]

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 ]