All Questions

In order to generate circular polarization in a crossed-yagi, a 90° phase delay is required between the horizontal and the vertical antenna. In practice, this is achieved either by making a mechanical ...

Looking to build a crystal radio, need help with the coil. I'm looking to get something to work with 1/4" thin wall copper tubing. Already have some nice diodes and whatever capacitors/resistors I ...

It's easy to understand, conceptually anyway, the difference between a horizontally polarized antenna and a vertically polarized one, when referenced to ground. However, when they are pointed nearly ...

In the context of wondering how to convert characters per minute to words per minute, it was pointed out that CODEX and PARIS are used as typical words for measuring speed of CW operators. As the ...

I have a cheap baofeng uv-5r, and I sometimes hear an intermittent transmission which pulses past the squelch threshold with periods of dead space between, roughly 0.75 seconds or less. My job uses a ...

I'm working out the science behind mounting an antenna on a vehicle, and I came across the concept of ground planes. This answer says that longer is better but don't worry about it too much, but this ...

I would like to make a 1:1 balun with М1000НМ ferrite core (magnetic permeability - 1000) and 1 mm thick copper wire using triple bifilar winding. Unfortunately I didn't manage to find a clear ...

I was searching for DIY end-fed antenna. Some of the articles I found say that for a 1/2 wavelength end-fed I need a "small to no counterpoise" (with a lambda*0.05 m counterpoise), but some other ...

I was using a 10-ish meter wire as my HF rx antenna. That's all I can install in my QTH. However I realised that my ~10 m wire can be turned into an end fed dipole for 20 meter band. But there is a ...

I am putting a run together from my shack to a new 2 meter antenna I've built. I'm blessed to have many trees on my property and I'll be placing the new antenna about 90 ft from the ground by hanging ...

I wish to fit this on the house gable end, however the location has a metal phone line bracket that will be just bellow the antenna radials. Will this cause any detrimental effects?

Are there combo handheld radios for CB and amateur radio? If so, is it practical?

This GBTimes article A tiny Chinese satellite is orbiting the Moon and allowing radio amateurs to download images links to this tweet which shows a high gain UHF? antenna pointed at the Moon, and that'...

I'm building a radio communication system for an amateur rocket project. We've decided to use LoRa 868MHz system. My question is, which antenna for the ground station will be the best choice? We're ...

Can someone tell me why exactly a transistor non-linear power amplifier will amplify an AM signal without noticeable distortion, but will distort an SSB signal, giving the familiar scratchy sound ...

I am looking for data that compares the number of transmissions per month or year among the various digital modes such as DMR, D-star and Fusion. I want to see how popular these technologies have ...

I'd like to estimate the power density from a 13.56 MHz power source in a near-field WPT (wireless power transfer) scenario. Using a spectrum analyzer with a receiving antenna will give the E-field ...

And also, can anyone tell me how? Using Arduino or any other way ...

Forgive what may be a basic inquiry from a new enthusiast. I am new to amateur radio, just barely passed Technician and General tests. I am also a pilot and have an RR class licence. I believe that I ...

I have one straight horizontal wire antenna 35 meters (114.83 feet) long. I want to make it work the best on average for the 80, 40, 20 ,15 and 10 meter amateur bands. Can anyone tell me the best ...

This task is our milestone, even the lecturer doesn't know how to do it, I will be grateful for even the smallest clue, thank you in advance. There are given two, identical, parallel, short dipoles ...

I have a G5RV Jr. antenna on a fiberglass mast at 10m height. The only metal on the mast is a 1/8" thick steel guy ring with stainless steel snap links, plus a few small metal screws. Hanging freely,...

Q1.1: Why can a helix calculator not be used for linearly loaded antennas? Those online calculators suggested that the turn pitch/wavelength should be around 0.25. However, a typical linearly loaded ...

After reading the commentary in this question and its answer, it's apparent that ham procedures/norms/protocols/etiquette are substantially different than military and public safety radio procedures. ...

I was reading up on a radio review, and it mentioned something I was not familiar with, "Busy Channel Lockout". Unfamiliar with the term, I did an Internet Search, but didn't get back much, and for ...

I've build an air capacitor like the one described in this article, although I used 1 mm thick single side copper boards (FR4) instead of solid copper sheets. I would like to use such capacitors in my ...

I got my Extra-class ticket some time ago. I was able to discover what my score was (the number of questions I got wrong). However, my examiner was not able to tell me specifically which questions I ...

Currently my location is Nepal. We use the ICOM f-7000 radios without the antenna tuner. We use the frequencies round about 5-9 MHz, for communication over distances between 150 and 400 km. During ...

I am currently looking for a good solution to create a simple VHF dipole connected to a RF preamplifier / band pass filter. The intended use is 88-108 FM RX. I see basically two solutions for a rigid ...

I would like to use a shortened whip antenna with a coil in it's base, e.g. OPEK HVT-400B. My transceiver maximum power is 100 W (and antenna's - 120 W). To make the antenna work I need counterpoise ...

I'm in the "information gathering" phase of a RF Power Meter project and the design I fancy (W7ZOI Power Meter) calls for a feed-through capacitor at the output port. I understand that a feed-through ...

To receive the amateur radio license Klasse A (HAREC) in Germany it is since 2005 not required anymore to pass a CW exam, due to a corresponding change in the Radio Regulations. However, the exam is ...

I need to create a setup where I have three radio transceivers (869.4MHz) setup in a straight line. I need to be able to communicate, in both directions, from the centre pole to the outside two poles,...

A great many moons ago, I spent a 24 hour period with a HAM radio connected to a PC, and listening to transmissions from a massive number of sources. Some of the transmissions included Morse, RTTY, ...

I have a lot of 'donated' coax that has been given to me with unknown provenance. I'm wondering what things I can do that can determine whether I keep it or send to the tip? Some of the things I have ...

When designing a resonant circuit, for example as a local oscillator, the product of $L$ and $C$ determine the resonant frequency according to $$f_{res} = \frac{1}{2\pi \sqrt{L C}}.$$ This means that ...

In most schematics of ham radio receivers and transmitters the inductor is mostly given specifically as the number of turns around some certain toroidal ferrite ring (for example). This corresponds to ...

I have a Yaesu FT-101EE, D-104 Mike, MFJ-929 Antenna Tuner, 80-10 OCF Dipole Antenna. When ever I key up for more than a few seconds, the wifi network goes down for a couple of minutes disconnecting ...

Flying around the area, I noticed this from the air - I have tried doing some searching but have been unable to find the name of the design or its specific use; What is this massive antenna, and what ...

I have been monitoring power of a P25 control channel (at about 850MHz). For awhile, 24 hours a day. I graphed the power over a couple of weeks and it is almost sinusoidal, decreasing significantly ...

I'm going to buy Yaesu FT-891 as my first transceiver. I know that I can measure SWR with it if I use FM mode and minimum power, which is 5W for this transceiver. However, I don't know whether it's ...

I've notice a couple of times over the past couple of weeks that the noise floor, particularly on 40 and 80, is exceptionally high as the grayline passes me into night. I'm looking at the general band ...

I need to calculate the antenna gain in both dimensions: azimuth and elevation. The datasheet of the antennas I am using has two different radiation patterns, one for the elevation and one for the ...

My understanding of why movie characters say "break" and "over" during radio conversations is based on this answer, which says that people using half-duplex devices often will want to let others on ...

I'm attempting to follow this white paper in order to build an antenna. This is my first antenna and as such I have a rather simple question. DIY 137 MHz APT Weather satellite antenna by Adam-9A4QV ...

I'm looking at dual band (2 m & 70 cm) antenna designs for my next project. A very interesting one to me is the Mighty Woof, which is essentially a fan dipole made of copper pipe. Would the ...

I'm using symbol sync block (symbol_sync_ff) on my project and i use many different sps values that i need reset on runtime. I'm trying to reset sending clock_est tag. Is this the right way to reset ...

I live in Moscow, Russia and use DIY indoor magnetic loop antennas to listen amateur radio. Recently I received quite strong signals from Italy (20m, IV3UTV) and Slovenia (40m, S51CK), both operators ...

My unit is 25' by 25' each side and the front is 22' across. The overhang is about one foot with aluminum and vinyl underneath. If I wrap an OCF dipole (fed with 4:1 balun) around this overhang in ...

I'm really new to this, and I was wondering how the whole PTT system works? I have a headset with microphone, and a Baofeng UV-82 radio. I know the radio has its own PTT button, but is there any kind ...