10

I've not personally built antennas from scratch, but I appreciate my antenna analyzer just for being a good instrument — making the invisible aspects of my antenna system visible. Compared to using a SWR meter for the purpose, an antenna analyzer: Displays more information. A SWR meter still gives you enough information, in the sense that you can try ...


7

My name is Alex, I'm the head of technical support at RigExpert. This is actually an interesting question. Our engineers could not give an exact answer why the schedule in the second case behaves strangely. I can offer to perform another experiment - to measure the parameters of the RG-8/U coax cable using the analyzer and the AntScope and AntScope2 software....


5

No power light could just be a burned out bulb or dead LED (I have a 259B...don't recall if the power button ever lit up). If you don't have anything connected to the antenna connector, then it's perfectly normal for the SWR meter needle to go all the way to the right because it's indicating a high SWR. Put a 50 ohm dummy load on the analyzer and see what ...


4

An antenna analyzer is not necessary. Sure, it's handy. A VNA is even handier. For this equipment you're looking at something like $50 USD for a NanoVNA, up to many thousands of dollars for a lab grade VNA. If you just want to know if you need to trim a bit off a wire dipole or not, and simply get on the air without toasting your transmitter, none of these ...


4

I get that reflections show up as peaks on the IR graph, is that it? Yes, that's essentially it. Note that the reflections can be negative or positive: for example if you try it with a short at the end rather than an open you should get a negative spike in the impulse response. Falstad makes (I think) a pretty intuitive way to demonstrate the concept: ...


4

With the battery case detached from the device, look at the side with the copper terminals. You should see several seams that can be exploited with a sufficiently thin shim. I carefully used a box cutter on the right hand inner seam of the battery case and separated the battery case into two pieces without actually cutting or breaking any of the small ...


3

After much troubleshooting, I was able to resolve the above behavior by running AntScope2 in compatibility mode for "Windows XP (Service Pack 3)" For the record, I am running Windows 10 1909.


3

I couldn't live without my two antenna analyzers -- I may even get a VNA (vector network analyzer) although that is not necessary for simple antenna analysis. I own both the MFJ 259B and the Autek Research RX Vector Analyst VA1. Although both do roughly the same thing, they have a few different features and I will touch on a few of those. Besides digital ...


2

You can put a one-turn loop on the analyzer and use that to couple into the trap. There will be a dip in SWR where the trap is resonant. Here's a picture from the RigExpert manual: Connect that single-turn loop as if it were an antenna, and do an SWR sweep. The notch is the resonant frequency.


2

A coaxial collinear antenna will have a usable bandwidth of 1-2 MHz at most. Sweeping a +1000 MHz bandwidth and trying to interpret the result is not a meaningful exercise. You should narrow the sweep range of your analyzer to perhaps 5 Mhz centered on the design frequency of the antenna in order to get initial data. From there you can further restrict the ...


2

Measuring received power is pretty straightforward. Set up a receiving antenna some distance away. Make it at least 10 wavelengths, but even farther is better. Make sure the receive antenna has the same polarization. Transmit a carrier at a fixed power. Read the received power at the receive antenna with your spectrum analyzer. If it's more convenient, you ...


2

I've been a ham since 1963 and have built all my own antennas. Yagi beams—wire beams—loops—verts, etc. Back in those days all you had was a SWR bridge and maybe a grid dip meter. The most important thing, I think, is a booklet or some kind of articles on antenna design. They will give you accurate lengths and feed line info that should get you up and ...


1

The TX ranges supported by those units are the downlink ranges of recognized cellular allocations and the RX ranges are the corresponding uplink ranges — e.g. LTE Band 2 has downlink from 1930-1990 MHz and uplink from 1850-1910 MHz, and LTE Band 4 has downlink from 2110-2155 MHz and uplink from 1710-1755 MHz. Together they make up the ranges supported by the ...


1

Well, since I resolved mystery, here is short explanation. I built my own dip adapter exactly as explained by Phil - single loop of wire connected to output of MFJ-225. However, putting loop at the side of trap (as presented in RigExpert picture) did not work. Dip measurement is quite insensitive, so I had to make sure loop is set at the center of trap ...


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