2019年8月9日 · $\begingroup$ @BrianK1LI so, the QFH is supposedly an excellent antenna for satellite reception since it's truly omnidirectional for 180 degrees. I was thinking of using it to listen to 2m sats, and later when I get my license, use it to tx as well. $\endgroup$

2024年1月27日 · So maybe I can convince myself that this allows you to go from an unbalance 50-ohm coax to the balanced feed that the QFH really should have. I'm not 100% certain on that point. Design 2 really confuses me because the connection point into the shield of the coax is an arbitrary distance apart depending on the length/width ratio of the helix.

2023年6月28日 · Just finished building a QFH antenna to see if I can capture the new Meteor M2-3 and improve NOAA APT. I built it out of 1 1/4 inch PVC water pipe, and isolated aluminium fence wire, I printed a cap that also serves as stability supports now I'm …

Due to the construction complexity of a QFH antenna, I would consider a simple quarter wave ground plane antenna or a vertical 1/2 wave dipole as the ground antenna for this example. Either one would be kept at least 1 meter off of the ground via a non-conducting support with the top of the antenna tilted to ~60 degrees away from the line of ...

2020年1月25日 · Whilst the calculations using the calculator seemed to work well, instead of the intended 137.5MHz I found that my first QFH was tuned for 126MHz (made using speaker wire) and the second was at 135MHz (made using copper pipe), so neither are ideal for the NOAA and Meteor satellites which broadcast between 137.1MHz and 137.9125MHz, which I ...

2019年8月18日 · QFH is a "wave antenna" that captures signal by being aligned with the propagation of the EM wave in space. Beverage antenna does a similar thing at MW/LW frequencies (and is physically enormous as a result - it has to be many wavelengths long).

Hello! After getting mixed results with a v-dipole I decided to try making a qfh antenna, I followed the rough dimensions of another users qfh that I saw yesterday, intending to dial the specifics once it was roughly complete. For some reason it has a very high SWR, at around 12. My nano vna is fully calibrated and accurate.

2024年5月19日 · My antenna qfh ke-137 that I want to use for noaa apt is more responsive on the 990 MHz then (-31db) compared to the 137 MHz (-8.42db).

2015年4月27日 · QFH antennas are actually reputedly one of the best antennas for not being effected by their surroundings adversely. That is why they are used on satellites. Lots of hams use both 2m and 70 cm QFH antennas - often on the same mast- Just keep them at least a few meters apart - and again- preferably dont use them for transmitting without some ...

2022年6月28日 · Welcome to Reddit's own amateur (ham) radio club. If you are wondering what Amateur Radio is about, it's basically a two way radio service where licensed operators throughout the world experiment and communicate with each other on …