Amateur Radio Stack Exchange
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1500 questions
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3 answers

Can I use new 14500 batteries instead of AA with Yaesu VX-8DR?

In addition to the proprietary battery, that came with my radio, I also purchased the part allowing usage of three AA-batteries. That was about 10 years ago, before the appearance (and wide availability) of the 14500 standard. Simply replacing AAs…
Mikhail T.
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How to calculate or estimate surface area of required ground plane for a mobile antenna?

I don't have conditions for installation of a fixed 2 m/70 cm antenna at home, so I'm thinking of using a mobile magnetically mounted antenna on a conductive plate instead. So my question is: What are the rules of thumb for getting ground plane…
AndrejaKo
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Antenna tuner at the transceiver output confusion

I am a bit confused. Let's take a HF transceiver for example. My understanding is that the output impedance of the transmitter is 50 ohms. The impedance of the coaxial cable feedline is 50 ohms, and if we have a resonant antenna at the operating…
Engineer999
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bizzare CW on 2m

I'm currently in Kershaw, SC. Yesterday an automated signal popped up on a 2m simplex freq (147.455 MHz) and has been running since. It sounds like Morse, but it is random letters that don't seem to have any repeating pattern. After every seeming CW…
Aaron
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How to meassure a ferrite using a VNA?

I want to measure a ferrite toroid using a VNA. I would like to classify it for a whole range of frequencies but if it's too complicated I'm OK to just pick one frequency. I have 3 questions actually: 1: Is there a preferred test jig? My plan is to…
Jack0220
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Do these look like amateur radio antennas?

I am planning to move into a new apartment, and of course would like to install a HF antenna there, on the roof if possible. Today I noticed a small Yagi antenna on the roof of the building , more than likely for VHF, but more interesting, seems to…
Engineer999
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Will a HF beam antenna on rooftop building interfere with other antennas there

I am moving into an apartment on the top floor of a building and I intend to install a HF beam antenna for 20 to 10 meters, on the rooftop of the building. I notice that there are already some antennas installed there on the rooftop. Possibly TV…
Engineer999
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Is tuning at all useful for an antenna that is already resonant?

Say you have a resonant antenna that also has a tuner. Does this help at all? Can your antenna be "fine tuned" ?
NonYaBidnezz
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Are there an MTTF/MTBF/MTTR data on the typical tubes used in the FT-101/TS-520?

I browse ebay.com for used rigs in good condition and approaching my shoe-string and ... There appear to be a decent quantity of boat anchors out there - FT-101, TS-520, TR-4 to name just a few. By definition, a boat-anchor would date to the…
VU2NHW
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Can a 1A Field Day station qualify for the "Alternate Power" bonus?

We just finished our Field Day operations, and we're having a disagreement on whether we qualify for the Alternate Power bonus. Our 1A (single transmitter, emergency power) station was completely solar powered for the duration of Field Day, which…
W5VO
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How to center-feed a single wire dipole?

I have heard that it is possible to feed single wire like a dipole from the center-point without actually making two separate wires. How would I do this, what impedance would I expect to see, and what matching technique should I use to keep it at…
Skyler 440
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Phased array (rx only) with separate complete receivers

Is it possible to have a network of separate (but co-located) 'receivers' (antenna + adc) act as a phased array receiver? Supposing one can get very precise timestamping on each receiver, couldn't all the receivers be assembled as a phased…
Touisteur EmporteUneVache
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EFHW: better to get far end really high, or middle somewhat high?

I built a 40m end fed halfwave antenna and unun, and the wire is about 66 ft long. I have some tall trees nearby I can hang it in, semi-permanently. Which of the following would be better? A) hanging the far end nice and high, about 50ft, but then…
User5754448
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Using a Return Loss Bridge and Nano VNA to measure amplifier characteristics

One of the difficulties of measuring active devices like LNA and IF amplifiers with the Nano VNA is the care needed to avoid over-driving the amplifier input and, more importantly perhaps, to avoid blowing up the CH1 port during S21 (gain)…
Buck8pe
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Why am I not hearing repeater identification more often?

I just bought a 2m/70cm handheld. I programmed in the local repeaters and have been scanning them for a couple of days. Only about twice have I heard one of the repeaters come up and identify itself. From reading, my understanding is that the…
plafratt
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