440 Mhz J-Pole Antenna plansupdated
- Here is a 70cm (440 Mhz) J-Pole antenna that is inexpensive, and easy to build. Author use 1/2 inch copper pipe, and the associated fittings necessary. The dimensions arenít typical however, thisiswhat it took to get its SWR low.
The Hairpin Monopole Antenna
- Numerous questions have been raised concerning its performance, namely How can a balanced structure radiate? and Whatis its impedance? This article will attempt to answer these questions.
Some plain facts about multiband vertical antennas
- There is considerable confusion as to what exactly a multiband vertical antennais. The confusion concerns the method of feed, how much mismatch one can expect, how many radials are required, how the particular antennais built for multiband use, plus some other points.
Local QRM reduction
- It is not always possible to tackle the sources of local QRM. What remains is trying to reduce the noise level by means of your antenna system.
Learn how to reduce QRM and understand how cancell noises by PA0SIM
Antenna Gain on Trial
- Most people think it's a good thing to have and the more the better. However, thisis not always true - and the amount of gain is often not what it appears to be. Assuming higher gain iswhat you need, how do you determine what will give the best performance?
Quarter Wave with radials
- VHF quarter wave antenna mainly for scanner usage, The quarter wave antennais an easily designed and constructed antenna for whatever frequency you want, although with the following design, you may to limit it to the VHF and UHF bands due to the physical size.
Portable Wire Antenna
- W4ZT used thisantenna for Field Day and other portable applications. He built them for all bands between 160 meters and 6 meters. You can make them easily using whatever wire you have available and make the insulators from scrap plastic
- Hams have been putting stations in their cars since the Twenties. Today, there is great satisfaction in facing the challenge of installing a transceiver in our small cars and pick-ups, using somewhat inefficient antennas
Getting Started in SW Listening
- Excellent and exaustive guide to shortwave listening offered by monitoringtimes, includes operating guides, technical suggestions, buying guieds, antennas implementations and more, all whatis needed by shortwave listening beginners.
- Freeware antenna software that lets you see what the polar diagram of your rotatable beam actually looks like where it is operating.
With PolarPlot you can measure the polar diagram of the antenna and check for abnormalities - compare plots taken before and after changes to the design or location - check the -3dB beamwidth - look at the front to back ratio - see the size and position of the sidelobes.