Use a TV coax and balun for a poor-man's OCFD?
Can I use TV coax and a cheap TV balun to build a poor-man's OCFD? Marginal performance is acceptable if it saves money. If I could listen to 10% of transmitters within a 100 mile radius that would be...
View ArticleFeedline and balun for 80m horizontal delta loop
I am new to HF. I'd like to put up an 80m delta loop. Due to aesthetic considerations I need to use coax to the shack. If tuned for 3.55MHz, I anticipate having a good SWR on 80m, 40m, and 20m. The...
View ArticleG5RV Jr. fed with ladder line and coax
I am a new ham and I was just given a G5RV Jr. I have about 20 feet of coax plus about 60 feet of 450 ohm ladder line I can feed it with. Can I extend the G5RV Jr. feed line with the ladder line I...
View ArticleWhat are the effects of different feed-line incidence angles?
Consider a dipole antenna fed by a coax (say, longer than the antenna) with a signal reasonably close to the dipole's resonant frequency. Various sources say that the feed-line should approach the...
View ArticleWhat is Electrical length in RF and how to electrically cut and measure the...
What is electrical length in detail? Why is it so that 1/4 wave , 1/2 wave dipole antenna works properly and not a full wave antenna? What is the role of electrical lengths in degree?
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Total cancellation in corporate feed network for patch antenna
I'm trying to build an array of patch antennas in order to receive a GPS signal. The idea is to build 4 patches and connect them with a corporate feed network. An example of corporate feed is this...
View ArticleHow do I use a signal generator + oscilloscope to measure feeder length?
I could relatively easily take the feeder down and use a tape measure but it’s more of a challenge to learn how to measure the length using my oscilloscope -Red Pitaya - but I have to admit I have no...
View ArticleOn a horizontally setup 20m delta loop I am looking to determine the...
Base of loop will be about 6 feet above ground. RG-8 or 213 will be used for the feed wire. Ugly balun as well.
View ArticleIs there an instance where you can directly feed a half wave dipole with...
Like the question says, can you feed a dipole with coax with no ill effects? Nothing else in the system, just the antenna and the cable.
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Excitation coefficient of a linear phased array
it's well known that in a linear and equispaced antenna array, the array factor is equal to:The array is then called uniform if $|I_n| = I$ is the same for all elements. The phase terms $\angle I_n$ is...
View ArticleWhat happens to the signal level if the antenna has high SWR?
I'm currently reading "Reflections: Transmission Lines and Antennas" by M. Walter Maxwell, W2DU. This book explains well why the energy is not lost because of high SWR during transmitting, assuming the...
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(When) does a transceiver re-reflect 100% of reflected power?
There has been a long discussion of one question here. Phil, W8II and I agreed that it's better to post a separate question.There are several sources (some editions of "The ARRL Handbook",...
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Can coax be run through the center of a radiating element without currents...
I run a λ/2 vertical dipole for 20M that's fed to a 1.5:1 balun at its center with coax that is perpendicular to the dipole (parallel to the ground), for about 30 feet before it comes down to the...
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