All Questions

The question came up during a club event, and obviously we checked the regulations. references: "Amateur Station Licence Guidelines" page 24 "Amateur Station Licence Guidelines" page 22 These ...

Approximately what frequency should my UHF Pi-Star be set on in the US? Is there a standard?

If I have an 1.8-30MHz isolator on my multiband antenna (80m-6m), should I still be able to transmit 6m?

Assume that one does not have access to a multi-million-dollar RF anechoic chamber. When testing an amateur radio HF or VHF antenna, how would one absolutely minimize the amount of any RF radiation ...

gnuradio packetize using access code for start sync packet, but another example attach the preamblee, so what the differences preamble and access code ?

In my ongoing process of building up to a homebrewed general coverage receiver/transceiver, a first step might reasonably be a crystal set, where a tuned circuit and simple, or even improvised, ...

I have operated at several stations - including my own - where a 40m beam is stacked above a tribander. During a rain storm, there is so much QRN on the 40m beam that the band is unusable, but the ...

I need to simulate 2 helix antennae placed side by side, and see the resultant radiation pattern. But after adding the second antenna with a separate and when I try to simulate 4nec2, only simulated ...

An antenna system often consists of more than the feedline and radiating wires: such as fixed or tapped loading coils, LC traps, baluns, toroids, air variable capacitors, roller inductors, feed horns, ...

I am using four HackRF One devices that will be situated ~1000ft apart, and that must be synchronized. Running 4000ft of cable to connect their clocks is obviously not feasible. I am wondering what ...

I have an old Philips walkman that has AM/FM radio. I tried AM radio. Really I can get clearly 2 country radios. I catched very poorly 4 foreign radios or different countries, but they do lots of ...

I'm having little difficulties understanding the following schematic: I understand the part regarding current distribution. I understand why this schematic suppresses common mode current. Also I ...

Another question (Metal for antenna construction?) covered some aspected of this question, but the answers didn't exactly answer it, so I'll make it specific. Given 2 dipole antennas, resonant at the ...

Premise: I had a Baofeng GT-3 TP Mark III 8W stored and never used, this morning my nephew has found It and He tried to "play with It" transmitting at maximum power(8 Watt) despite antenna wasn't ...

Some receivers contain a noise reduction button or function. What does this noise reduction do? Is there more than one type of noise reduction? How does the circuit or software know what part of ...

I am sorry but yet again a question about GNU Radio. (I just started following some tutorials a couple of months ago and am learning about it. I am unfortunately not that proficient in it yet, but I ...

Hoping someone can identify this military radio... I spotted it at the curb and decided to make it a land-fill diversion project...

I’m super new to radio with nobody I know knowing it, so noob alert - plus some extraneous details in case you can comment on any of those. I got a pair of BaoFeng BF-F8HP radios with recommended ...

I've seen a lot of videos and tutorials on using the Quadrifilar Helix Antenna for receiving signals, but I haven't seen any material for transmitters. I'm just starting right now, but can a QFH ...

I am trying to figure out how to create a gnuradio program that can output some arbitrary waveform read from a file containing I/Q values. I would highly appreciate any guidance in this topic. Simple ...

Kindly, can anyone show me how to output CW tone or a Broadband Noise in GnuRadio in a sort of simple flowgraph if possible? Update: So, what I did is I tried not to overthink the whole issue here ...

I am new to GNU Radio. I need some reference to how to use FEC block in GNURadio. When I try to make encoder and decoder without modulation, its work as well, but when I using modulation and add ...

I posted yesterday asking how can I have signal inside my house which my house is obstructed by a hill from direct signal from the cellular's operator' Base Transceiver System (BTS). The schema of the ...

Background: Last night (and the night before) I was playing with my RTL-SDR and GNU-Radio again. Working with my FM Receiver, (which was working previously by the way), I detected that last night I ...

Consider a situation as below. I am stay in a farm field, which my house is 9.4km distance from the nearest and the only one BTS (Base Transceiver System), a cellular antenna for transmit and receive ...

I recently bought a cheap stereo amplifier with built in FM receiver from Amazon at the first link below. Testing it out today I found the FM reception to be sub-par. All of my local stations that I ...

What are CW skimmers, especially with regard to spotting networks? Are there more than one (of each)? How do the skimmers interface with spotting networks? (Or are they combined into a single ...

I'm new to APRS and trying to setup a RaspberryPi APRS GPS Tracker. I've installed Direwolf and configured it, my transceiver transmits the signal, and I've decoded it with GQRX via an RTL-SDR and I ...

Here is my measurement to a piece of RG6 cable. It is around 30cm cable. On the shield is written COAXIAL CABLE 5C-2V 75 ohm. From my measurement I got data as below: From that table, we can see that ...

I am traveling to El Salvador later this fall, and was wonder if there is any reciprocal agreement that would let me use a US callsign while there? If so, what privileges would I have there based on ...

I’m trying to be less of an appliance operator. To that end, I recently came up with a simple project that I thought I could figure out and build entirely on my own. I was wrong. My goal was to ...

Here is my C-Band parabolic tv digital receiver. As shown by the pictures, the incoming coax cable (INPUT) connected both the outer and the core. One goes to digital receiver 1 (receiver 1), and ...

I'm starting design work on a two-tube (two-valve, for those who prefer that term) reflex-regen receiver that I hope will cover AM broadcast through 160m-10m -- both amateur bands and those "in ...

The second R in ARRL stands for Relay, but is that still as relevant in the 21st century? Has it been relevant since broad damped-wave spark transmitters were supplanted with tube-generated CW, which ...

I would like to make a match half wave length (λ) dipole antenna (or probably a short dipole antenna). So I would like to make it by measure using LCR meter. What I am still confuse is about what is ...

Consider the picture below is design of half wave length (λ) dipole antenna. I read some explanations saying that it is the best design to get the optimum transmit power. Half wave length (λ) is from ...

Have you used an SSTV decoding application on an up-to-date version of macOS? Which one, and if you built from source, can you share the steps you took to do so? I do not know of a single working ...

There is an unknown ferrite toroid. I would like to figure out whether it can be used in an audio transformer, or maybe in a 1:4 transformer on given HF frequency. The experiment I came up with is ...

I'm planning to build a two-tube reflexed RF regen receiver soon. I'm examining methods of controlling the regeneration — it needs to be possible to both initiate and halt oscillation in all bands (I ...

I was wondering what happens when you directly electrically couple the transmitter antenna to the receiver antenna? Particularly I’d like to know what happens for FM radio broadcast. Since I don’t ...

I want to buy an SDR RTL USB dongle and I'm looking for one on Amazon. I currently saw ones from 100 MHz to 1.7 GHz. I can't decide and I know almost nothing about radio, but I want to experiment ...

I tried to understand the physics of Fuchs antenna and there is one thing that I don't quite understand. This is probably a very silly question, but I spent a lot of time looking for an answer (books, ...

I tried to build a multiband EFHW antenna as described in articles by PA3HHO, PD7MMA, G0KYA and many others. I decided to start with a short 40/20/(15?)/10 meters version without any loading coils. ...

For a modern rig, any rigs that come out within the last 20 years. How long would it last in storage? By that, I mean "dust it off and plug and play". Assume it is in a dry and cool place, without ...

Is there a legal (U.S. FCC) or a commonly accepted standard requirement for SSB opposite sideband and and carrier suppression for either manufactured or kit built transmitters? Does the 43+ dB down ...

Long ago, it was fairly standard to provide lightning protection for outdoor radio antennas by installing a large double-throw knife switch -- antenna leads to the center, radio on one side, ground on ...

I'm having trouble running a simple flowgraph with an osmocom source and a qt gui sink. If I run the file with a waveform generator instead of the osmocom source, all is well, the plots appear as they ...

I've been writing a SciFi story, and it calls for something very unusual to happen. I'd like to check this idea for plausibility, but as I'm not a radio ham myself, I don't know if this already exists ...

I am building a 1000W microwave kiln for glass jewelry. The internal capacity needs to be around 5 litres. What internal dimensions of the cavity should I avoid, or strive for, to ensure even heating....

I'm new to amateur radio, and as a beginner project, I wanted to use some of the basic components I have to create an AM receiver. Anyway, what I'm trying to do is create a simple AM receiver that ...