Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

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1500 questions
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1 answer

Cell Tower distance measurement

I am developing a hobby project to detect/measure the distance between my cell phone and a cell tower (GSM tower). I am newbie. I don't even know whether this is possible or not. I have following hardware: Raspberry Pi 3 RTL2832u I am planning to…
Avadhana Technologies
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Powering transceiver and SWR/power meter from same supply?

I'm mostly sure this will be ok, but I'd like to confirm. I have a switching power supply (can't remember the model right now, but it's for ham use, 13.8V/30A) and I'd like to power both the FT-857D as well as the power/SWR meter from it. Is there…
Rimio
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How important is the impedance and resonance of a receive antenna?

I'm very new to shortwave radio, as evidenced here: Can an antenna be too powerful for certain receivers? I want to build a longwire receive-only antenna for the HF frequencies. I've been using the source: SWL - Shortwave Listening as a guide, but…
fishfritters
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Lightning strikes nearby and coaxial cable

A direct hit on my home by lightning is very, very unlikely. However, many lightning strikes that hit Earth nearby are by far the main hazard for ham radio gear (in my opinion, after 60 years in the hobby). The huge electromagnetic pulse generated…
user10987
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8 answers

BF-F8HP: "Radio did not respond" when trying to use CHIRP

I'm trying to program my Baofeng bf-f8hp with the chirp software, but as I have to do, "Download From Radio", after I choose the appropriate maker, product and model, all I get is an error message which reads, "An Error has occured: The Radio did…
IX Mendoza
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3 answers

Will an iron chimney work well as an antenna?

There is an iron chimney near my house that is not used anymore. It is ~15 meters in length and ~0.5 meter in diameter. How good will it be as an antenna for rtl-sdr?
vasili111
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1200 baud packet radio can't communicate

I'm toying with a simple 1200 baud packet radio I built. I'm attempting for it to be compatible with APRS, which uses the Bell 202 signaling, 1200Hz for mark and 2200Hz for space, which I assume map to 0 and 1 respectively. However it's not…
Adam Davis
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Can an antenna be too powerful for certain receivers?

I'm brand new to shortwave radio and have been researching what kind of a receiver to get. I'll use it on the antenna I'll build (longwire, 50-100 feet) for shortwave listening; no transmitting. Right now I have my sights on a Tecsun PL-360 as it's…
fishfritters
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Why should I practice one month before a contest, rather than the week before?

I've seen suggestions that it's better to practice a month prior to a contest, rather than at any other time prior to the contest. What is special about a that time frame that it would be suggested so often?
Adam Davis
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What is Norton's transform?

This article from Itchen Valley Amateur Radio Club describes an interesting technique called "Norton's transform": This results in a negative capacitor, but in a circuit where there are other parallel capacitors which can be combined, the result…
Phil Frost - W8II
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I would like to listen to a red roadster in space

I have been listening for signals (any) of the Space-X Falcon Heavy. Just out of curiosity. And I am wondering if anyone has received any. According to the Falcon-9 User Guide table 4.6 looks like this: Although it mentions "Falcon launch vehicles"…
Edwin van Mierlo
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HF/VHF antenna for high altitude balloon

I'm working on the design of a dual band transmitter for use on a high altitude balloon. I'll be transmitting on 2 meters and 20 meters (APRS and WSPR) with about 50 mW. To keep the weight to an absolute minimum, I'm designing it to use a single…
whalphen K8VFO
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QSL cards and distance minimums

Newly licensed HAM here. Are QSL cards only exchanged during DX, or could they be exchanged with local contacts as well? How does one request a card? I’ve heard there are bureaus that route cards; is this the most appropriate way to send a card?
djdy
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Can a vertical antenna be used for NVIS?

I know that verticals are normally chosen for their low angles of radiation without obscene heights, but I'm not especially interested in DX and am primarily looking for local coverage via NVIS. I've not had great luck with dipoles at my home…
William
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How to access a P25 repeater?

Are there any special instructions for accessing a P25 repeater? What makes it different from a CTCSS/PL-tone-encoded repeater? What special features does a radio need to access it?
Dan
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