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8 votes
Accepted

Do you need to analyse the SWR of your radio repeatedly? Or periodically? If so, Why?

If nothing about the physical situation changes, then the SWR will not change. But something might change in the long run, perhaps: Damage to the feed line (water intrusion, sun damage to insulation, ...
Kevin Reid AG6YO's user avatar
  • 24.6k
7 votes

What does an antenna analyzer tell me about these coaxial cables?

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 ...
Alexander Antonov's user avatar
7 votes
Accepted

Measurement of antenna with VNA does not match its specs

The NanoVNA isn't exactly precision equipment, and the Linx datasheet specifies a maximum VSWR of 2.3, so it's possible the antenna is within spec (barely). You could double-check your calibration by ...
Phil Frost - W8II's user avatar
5 votes

Faulty MFJ-259 - meter hits end stop on power up

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 ...
imabug's user avatar
  • 689
5 votes

Measurement of antenna with VNA does not match its specs

In addition to Phil's excellent answer, these specifications are in an "ideal" free space. Having your NanoVNA in close proximity to the antenna (even having the antenna lying on a wooden ...
Dieter Vansteenwegen's user avatar
4 votes

Rig Expert AA-35 ZOOM Amateur Band coverage in the United States

60 kHz is about 5000 meters in wave length so yes it does go below 2,200 meters. The Rig Expert AA-35 is an antenna and cable analyzer. While often used by amateur radio operators, it is not ...
Jim's user avatar
  • 1,703
4 votes

Diagnosing antenna problem with RigExpert AA-600

@hobbs has the correct answer - look at the VSWR only, and see where the antenna is working. The antenna analyser, and any network analyser, measures the magnitude and phase of the reflection ...
tomnexus's user avatar
  • 11.3k
4 votes

What does an antenna analyzer tell me about these coaxial cables?

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 ...
Phil Frost - W8II's user avatar
4 votes
Accepted

How can I replace the NiMH battery in an old RigExpert AA230 Antenna Analyzer?

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 ...
Paul's user avatar
  • 1,455
3 votes
Accepted

How do I get my Windows 10 PC to consistently recognize my RigExpert AA-35 ZOOM?

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.
K8KV's user avatar
  • 377
2 votes

Is it possible to measure antenna trap with MFJ225 without help of PC?

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 ...
Phil Frost - W8II's user avatar
2 votes

Why Coaxial Collinear Antenna Gives Strange Graph of Frequency Sweep vs SWR?

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 ...
Glenn W9IQ's user avatar
  • 18.6k
1 vote
Accepted

why is 3rd order intermodulation for 2110-2155 = 1710-1755?

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 ...
hobbs - KC2G's user avatar
  • 12.4k
1 vote

Is it possible to measure antenna trap with MFJ225 without help of PC?

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 ...
Pedja YT9TP's user avatar

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