All Questions

Similar to Will stainless steel bolts work with my copper antenna? however my concern here is with electrical properties. With copper antennas I never gave it much thought... just solder the wire. I ...

I have a GNU Radio Companion flow graph, where I have the following connections: 440Hz cosine wave throttle block audio sink All of the above blocks use the same sample rate (48KHz). When I ...

Can I feed a folded dipole constructed of hollow tubing by threading coax through the element to create both an impedance transformation and balun? I have fed coax through the tubing of the dipole ...

I'm installing a new antenna mast to hold one or more antennas. The new mast will be strapped on to a chimney near the center of my house. Coax will run down the mast, across the roof, down the side, ...

How hard and expensive would it be to send a file from my house in London to a coastal area in Spain? It would most likely be software I want, so it must transfer perfectly, however if it is feasible ...

There are a ton of old USSR Gunn diodes available on ebay and I'm looking for a cavity that can make use of them. I am willing to machine one myself if necessary, but I'm unable to find any decent ...

Why line of sight communication links have a restricted range for a given tower height? Is it only because of the Earth's Curvature?

I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M. I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide. While I was at it, I ...

5 wpm is easy to learn and better than nothing in emergency. Speed Morse Coding is fine for "sport competition" I am trying to find out which is the typical speed for what I call "conversation" and ...

What are the effects on signal propagation if this ground plane is just a metal object and what are the effects if the ground plane is actually grounded? I am asking this question because someone ...

What is the definition of these terms? Would a system with signal to noise ratios of uplink 100dBHz and downlink 80dBHz be downlink-limited?

If I'm building a vacuum tube HF transmitter (say, 40 m band), obviously the simplest mode to build is CW; it's common to key the oscillator input to the final (in order to keep the oscillator running ...

Using software defined radios I can generate and demodulate a DVB-S2 signal live. I'm wondering if I can use this to send single pictures over the air using as narrow BW as possible. Using QPSK and a ...

The specs of the Elecraft T1 tuner say, that it can match a 10:1 SWR. What does that mean in terms of impedance ratio? What antenna impedance can it match to 50 Ohm then? Or is it not that easy?

The solution for the voltage in a transmission line can be written as: $$V(z) = V_o^+ e^{-jkz} + V_o^- e^{jkz}$$ The voltage $V(z)$ is the difference between the conductors of the line at a certain ...

Phones will receive signal from many pRRus. Should I average the antenna gain and all the path-loss (both line of sight and no-line of sight)? Or should I sum them all together?

If I get a German Amateurfunklizenz, will I be allowed to experiment with non-communication radio technologies like radar? Obviously, I'd still adhere to using allocated ham bands, stay within power ...

I can't find my Baofeng DM-5R in the CHIRP list of supported radios. I've been told that I should try by telling CHIRP to assume a different radio from the DM-5R - perhaps the UV-5R!? Do you know if ...

Are jammers relate to electronics or electrotechnics , why ? Please ,tell me the main difference between electronics and electrotechins and why we can classify jammers as electrotechics or ...

Last night there was a power outage at home. I was able to see a LOT of stations on 20M (FT8). As soon power returned, all of them disappeared. You can see in the waterfall very clearly when power ...

If an antenna needs to be mounted on a metal structure what would be needed to avoid interference? Are there just some specific length to avoid or it is better to be separated by some insulator? As I ...

TL;DR Laptop keeps switching between Signal Link audio output and speakers. Problem goes away when I turn TX knob down far enough on Signal Link. I just bought a SignalLink and have it connected ...

I recently bought this tube for use in an art project and would like to know what it is and what it was originally used for. Unfortunately, the silkscreen labelling on the glass envelope was worn off ...

I am new to RF field and trying to use an Archimedean Spiral Antenna design from this paper to capture 915MHz RF for the P2110B power harvester chip. The estimated antenna impedance is 188 Ohm (see ...

I noticed that the pinout for cheap Baofeng connectors has +V available. I'm interested in powering some electronics directly from this connector. When unloaded, this seems to have about 3.3V on it, ...

I've been looking at options for a high-gain directional antenna recently, and I've noted that there are commercially available parabolic antennae for the shorter bands -- specifically 70 cm, with an ...

I understand that Wi-Fi transmits on 2.4 GHz or 5 GHz whereas local ham repeaters transmit around 147 MHz or 450 MHz. What differences would be needed in antennas tuning into either of these ...

I'm running a feed line from the end of my amplifier to the antenna for HF transmissions. I'm using RG8x / mini 8. There's an existing pathway through my house I'd like to use that has a cat 5e ...

I have a new TYT MD-380; it works well for DMR channels, but on analog, the squelch doesn't seem to open when it should. I'm relatively new to ham and my first suspicion is user error, but it's ...

I was at Anaheim HRO and few guys there were talking about an MFJ all band vertical antenna that does not need radials. I forget what model number it is but it is one of those "wife pleasing antennae" ...

I just purchased a UV-5R to hopefully integrate into business class radios my company uses. Do I need a technician or other class FCC license to operate these only on the frequencies I already access ...

I am working on my 80m and 40m CW transmitter and ran into a problem: I need to match the high impedance of PL504 to 50ohm coax, a Pi match seems to be the best, but I don't know how to calculate ...

We have a question about the algorithm for conversion from coordinates into grid squares here, and this is an extension of that. I've noticed that there are several web-sites (for example here, or ...

Would a disconnected wire or conductive mat below a low height antenna reduce ground losses? A tuned length of wire under a wire antenna might be suitable for NVIS gain. But would a bunch of space ...

I have a couple of HTs with channel scanning features. I imagine setting the radio to scan mode takes more power than just listening to a single channel, but what rough order of magnitude? Will I lose ...

Is it possible to set a gnuradio flowgraph to record with a File Sink a fixed number of samples? I would like to use this wave as a reference. Thank you!

I want to base the output network for a 500W push-pull HF amplifier on "A 250W Broadband Linear Amplifier" described in Chapter 17 of the 2014 ARRL Handbook. I need advice on whether and/or how the 1:...

I'm asking this because of the comments in this answer, that imply that steel (mostly iron) has similar characteristics to ferrite. Specifically, it is implied that inserting solid steel into a ...

I want to build an ladder SSB filter using 8 MHz quartz resonators. I don't have frequency meter but I have NWT-70. How can I match crystals to build a good filter? What kind of parameters should I ...

I'm new to amateur radio, and I would like to listen to those satellites in the orbit. Where do I start? What types of amateur radio satellites exist?

Are transmit antennas the same as receive ones? I am making a extended Wi-Fi comms CCTV camera.

lightning damage can be extensive and costly, its even life-threatening. If I have properly grounded the equipment and have a Surge protection device, do I have to disconnect the antennas during the ...

I wonder whether the source code of VE6YP (Tony Field) coaxtrap design program (link 1, link 2) was ever published or described. As a Mac user I'm having little difficulties using this software and I ...

Not sure if in scope for ham SE. I'm very new to this. Most wifi repeaters contain an actual router and two radios set up to receive and transmit at different frequencies. Why can't we have a wifi ...

I am trying to put together a vertical pole style antenna with a loading coil housed at the base using a plan very similar to the one described in this ARRL article. I am trying to understand how to ...

I have an Ettus E310 from which I send some data via ZMQ to a computer. On the remote computer I am running a Qt GUI in which I am displaying a FFT and a variable. After about an hour, the GUI needs a ...

I managed to successfully install Winlink on my Ubuntu operating system but it is not completely functional yet. I don't know which COM my computer is set up to use, and there are a lot of them ...

My friend is blind and would like to take the amateur radio license exam. I understand that the question and the four possible answers can be read to them, and that is fine. The one question that we ...

I have to measure the S parameter for a rectangular sample with an antenna that works from 2 to 18 GHz. I need to measure a large band from 5 to 15 GHz and I have a problem with the known F.F. (Far ...

I'm working on a kite-supported antenna for an 80m QRP rig -- to be flown at beaches, on mountaintops, and possibly other places where I want to work HF but don't want to lug poles or give up ...