All Questions

Lets say there is a reception antenna connected to a detection system with a coax, and a transmitter sends a plane wave. What happens is that the antenna gets a certain power, following the [...

I want to know the best copper wire or tinned copper wire for a fan dipole for 160, 75, 40 meters. It would be coax fed and I would like it to handle 1500 watts or more. I would like 65/30 strands of ...

Is there a way to identify this coaxial cable? I am interested in model and parameters such as epsilon, diameters etc. There is nothing written.

I'm building a dipole antenna for 433 MHz, first one ever. I will have to use a ferrite bead to balance the feed. How many decibels of attenuation should I expect from the ferrite bead?

Apologies in advance if this question is too straightforward. I was browsing for some information about the dimensions of Yagis. This yagi listed by PEOSAT, called Cue Dee 15144AN, is stated to have a ...

I need to ground an upper floor shack, but I do not know very much about grounding. I have a Pathfinder dipole by Radio Wavz and I don't believe I need any RF grounding, but as for safety and ...

I'm looking to connect my Yaesu FT3D ham radio to a Linux laptop via bluetooth. I understand it only does audio over bluetooth, but for my use case that's acceptable. My end goal is to run Direwolf ...

I've managed (thank you FT8!) to have LOTW-confirmed contacts with the 6 applicable continents. However, on reading the ARRL page for the WAC award it says that you have to apply on paper and that ...

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 ...

When you respond to an FT8 CQ and the other side doesn't respond after a couple of your transmissions, what is proper etiquette? (Assuming you're working split and not transmitting on his receive ...

I just answered this question, and I wanted to know if any particular shape has been found to be successful for anyone. There seems to be a lot of research on IEEE that indicates that there should be ...

I'm starting to tinker with an RTL-SDR (generic, and cheap, so nothing fancy in any respect, hence the "pragmatic" in my question title). It's clear that the antenna provided (about a foot ...

If we take an iron disc in space that is spinning on its axis, no electron in sight for miles other than the disc. The disc is magnetized with 2 poles. Speaking from an electrical potential, yes the ...

EDIT: I have succeeded in getting the AM receiver to work, by replacing the AM Demod block with a Complex To Mag, and a Band Pass filter (this is noted as an alternative in the AM Demod docs). ...

So I see NASA has issued a geomagnetic storm watch for a possible G2-level storm on the 11th. I’m at about 53 degrees north geomagnetic latitude. Is this something I need to care about equipment-wise? ...

I think the far-field is significantly different in vacuum versus air, is this true? More specifically, when we talk about far-field, we mean the electromagnetic wave as a whole etc. but in the near ...

I have a problem on the understanding of a half-wavelength antenna. Namely, why is the half-wave antenna has a highest power emission. Considering Far Field factor F($\theta$), which is known from the ...

Depending on the parameters used in the link budget formula it seems that one may come up with a received power (dBm) larger than the transmitter output power (dBm). For example: Frequency: 50 MHz ...

I have a theoretical question about EIRP. EIRP is calculated by summing the power of the radio (the intentional radiator, IR) plus the gain of the antenna (dBd/dBi) minus the sum of the losses. The ...

I have this audio file (WAV) that I'm trying to decode using multimon-ng (also tried Qtmm AFSK1200 Decocoder). It should be using AFKS1200 but multimon-ng can't demodulate it and by the looks from the ...

I use gnuradio and fosphor to view the spectrum from USRP B210, default gain set to 34, output looks like concave as below: ...

Workflow as below: When file_source after file_sink,center frequency is not recorded and ...

In quite a lot of places below 7000kHz I see a repeated noise figure. A hum, then about 12kHz above it a "flapping" with beeping noise, and then about 50kHz from that whistling with three ...

I recently found out there are very cheap (down to under a dollar) adapters that convert the 5 Volts from a USB port to 12 Volts. Manny small QRP stations draw very little power. For instance, the ...

I have been reading and doing the steps on this webpage of GNURadio : https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation In the middle of the page, there is a section: "Using ...

Are there any good/useful "libraries" of RF noise out there? I know about http://www.arrl.org/sounds-of-rfi but it is pretty limited. (And I wish the screencaps showed the FFT rather than ...

I'm building HF kits 80m EFHW kit, and in the instructions it directs you to tie a knot in the antenna wire. I'm concerned of damage to the wire. I have found no source as of yet that indicates if ...

I bought a UV-5R Plus (8 watt radio in the same casing as a normal Baofeng), and I've noticed some strange behaviors. Occasionally when I key up on my local repeater, the radio turns itself off and on ...

I'm looking for advice for running coax cable to my shack on the second floor of my house. I'm planning to use this coax line for HF (recently upgraded to General!). I'm a newbie and I am very handy, ...

I have made a loopback flowgraph in GNU Radio companion to implement a 4FSK modulation. For the modulation section, I have simply adjusted the "chunks to symbol" block to map each 2 incoming ...

In the ELF-VLF frequency band,some background noise like Schumann resonances shows in the spectrum analyzer as peaks. I want to have a overview look of the background noise of ELF-VLF frequency band,...

Morse code in this doodle? think Interstellar (movie) https://www.google.com/doodles/googles-23rd-birthday

I try to use gnss-sdr these days with USRP B210. When I connect GPS antenna with RX port,gnss-sdr output well.But GPS antenna ...

I want to check the EM pulse between 3HZ-3kHZ with N9041B UXA Signal Analyzer,it seemed the only antenna I can use is Aaronia MagnoTRACKER,but the price is not affordable. Then I plan to make ELF-ULF ...

I have a question about "best practice" in regards to how the 2nd mixer IF port is coupled to (in my case) a 20m double tuned filter on transmit. I'm currently building out the transmit ...

I'd like to mount an antenna mast to the gable end of my house. I was planning for the mast to extend from ~10 feet above the roofline down to the ground. I've seen wall mounts specifically for masts, ...

I have a USRP B210 SDR that has only 56 MHz bandwidth. How can I automatically scan a wider bandwidth (like from 80 MHz - 5 GHz) without manually changing the center frequency in GNU Radio? In the ...

Various answers include 1/8th of the wavelength all the way down to 1/10th, but would 1/15th or even 1/20th of the wavelength be sufficient for a 60 meter (5 MHz) horizontal NVIS antenna?

I have a dipole wire antenna that is tuned to 14.0 MHz so that it has an SWR there of nearly 1:1. Is there a mathematical formula by which I can compute the expected SWR for other frequencies? I would,...

Is there a 2-3 meter long loaded dipole for the USB 40m ham band that I can use on a 2nd floor balcony?

Consider an array with same isotropic antennas, $P_{ele}^n$ is the input power of the nth antenna. As I consider antenna radiation efficiency = 1, the $P_{ele}^n$ is also the radiated power of the nth ...

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 ...

I'm new to the world of ham radio so this might be obvoius, but I have a Baofeng UV-82 which can transmit and receive up to 520MHz. I need to be able to transmit and receive on frequencies up to 1GHz. ...

I am moving into a new apartment in the city soon which is on the 24th and last floor of an apartment building. I will have access to the roof of the building also. I'm still trying to understand ...

I got a little tired of Si5351 and decided to build an analog CW transceiver. It's almost done and works pretty well. However, I discovered one problem. When I reach the VFO control with my hand the ...

I have been using a Par EndFedz Mk2 Trail Friendly 40/20/10 though using the matchbox from an EndFedz EF-QUAD (with Vibroplex’s blessing) so I could transmit at more than 25W. On all three bands I ...

I'm trying to visualize the frequency band utilization during a GSM phone call using SDR. Ideally, I would like to plot the whole 900 MHz range, i.e. 876-959 MHz. However, even setting the zoom to the ...

If you have preprinted QSL cards that have your home address and grid square on them, what's considered the most proper way to do a physical QSL exchange for a contact that was made while you were ...

Say you have a resonant antenna that also has a tuner. Does this help at all? Can your antenna be "fine tuned" ?

I'm a new ham (licensed back in the spring) and very new to HF (only a couple of weeks). One thing I've noticed in the phone bands is that things seem to rarely go the way all the articles aimed at ...