# All Questions

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170 views

### How do I radio? [closed]

What's the simplest way to make a radio station from my home? I just want to bump this city with some slick tunes. What do I need to buy and about how much am I to spend?
12k views

### Why are some electrical contacts gold plated?

Gold is really expensive. Why then would anyone bother to plate connectors with it? Does it have some unique electrical characteristics that make it useful?
4k views

### Is copper-clad steel a good material for wire antennas?

There are some people selling steel wire plated with copper for making wire antennas. Perhaps the most well-known brand of this product, Copperweld, makes at least two kinds of copper-clad wire, ...
47k views

### Effect of different metals for antenna elements

Other than rust, corrosion, and other reactions with air that would make the use of a metal unfavorable, how do different metals affect the performance? Let's give Yagi an example: Let's say I use 4 ...
7k views

### How to construct a loop antenna for receiving HF?

I have a unused hula-hoop in my garage, and I ran some stranded speaker wire around it once, and attached one side of the wire to the coax shielding, and the other to the coax core wire. Is this the ...
6k views

### International characters in Morse Code?

Does the official International Morse code include alphabetic characters other than the 26 letters of the English alphabet? If so, what are the most common other alphabets or characters that one ...
313 views

### What radio regulations apply in International waters?

What regulations apply to radio operations in International waters? How far offshore does one need to be? Does the answer change between registered commercial vessels and home-made rafts or canoes?
7k views

### Noise bridge use in antenna construction?

How does a noise bridge work? And how can a noise bridge be useful in building, testing, and/or tuning an antenna?
2k views

### Homebrew 2 meter Yagi construction

Here is what I have • A Baofeng Uv-82 transceiver • A 1/2 inch 10 foot PVC pipe • 3 1/4 inch x 36 inch Aluminum rods • 2 1/4 inch x 48 inch Steel rods (I know they'll rust, it's just temporary to ...
229 views

### Why do you have to be 18 to be a Volunteer Examiner in the US?

I am a 15 year old ham, and just got my Extra class. I was really bummed when I figured out I needed to be 18 to be a Volunteer Examiner administer. Why do they make that rule?
310 views

### How far from earth do FCC regulations apply?

So, I know people in the space station need a HAM radio license for operation. How Far exactly from earth do you have to be to transmit any RF wave you want without a license?
1k views

### Low parts count CW HF receiver?

I'd like to be able to provide my kids with the opportunity to build something a little better than a passive crystal set, but still very, very simple in terms of individual electronic parts count. ...
925 views

### Why do today's transceivers use LC filters rather than crystal filters?

Going through a number of schematics for today's receivers (Elecraft KX3, for example) I note that most use LC circuits for filtering. The wikipedia article for Crystal Filters suggests, however, ...
750 views

### Would I still be a valid volunteer examiner?

I'm currently an ARRL member, and a volunteer examiner under the ARRL/VEC. I find myself needing to cut back on expenses this year and may end up dropping the ARRL membership. If I do so, am I still ...
3k views

### How does a switching mixer multiply the two signals?

I understand what a mixer does, and when I see it in a block diagram it's obvious what purpose it serves and how it fits in the overall design of the radio. However, when I look at the schematics and ...
2k views

### How can I tell if a call sign is valid?

Many different countries have different callsign formats. The US call signs typically fit into a very well defined category, but there are exceptions even there. I'm looking for a way to tell if a ...
115 views

### Why do satellite tracking programs have to be updated?

So I've heard every once and a while you have to update your satellite tracking software because of the fact that the satellites are falling towards Earth. Why can't the program automatically ...
366 views

### Practical antenna for 2m line-of-sight over 7 km [closed]

I live 7.8 kilometers birds eye view from my friends house. We are in Denver, so there may be a bit of terrain but should be relatively flat. There are a few trees, and houses and maybe a few ...
364 views

### Is there a repository of modern Amateur Radio transceiver schematics? [closed]

I am looking for a repository (SVN ect) of modern Amateur transceiver schematics. Most of the designs you can find with a simple Google search either use tubes, or now obsolete and hard to find ...
4k views

### Why do we use LSB below 10 MHz and USB above 10 MHz when operating SSB HF?

As a relatively new ham operator, I understand that it is customary to use lower-sideband below 10 MHz and upper-side band above 10Mhz when operating single-sideband HF. I'm curious how we got to such ...
580 views

### Height and feedline loss tradeoff for VHF

Currently my 2m antenna is about 3m above the ground inside, my HF antenna is connected to 30m (2db loss) coax and is about 12m up. Since the loss for 2m is a lot more when traveling down such a long ...
88 views

### Where to find FM satellite information

I'm new to satellites and I am trying to find all the information for everything. Where can I find a list of all the operational FM amateur satellites with the down-link and up-link frequencies? ...
1k views

### Max El vs Max El Azimuth

I don't have much experience with amateur satellites and I went to the AMSAT website to track a few passes. Two of the terms are "Maximum Elevation" and "Max El Azimuth" I go to look up the terms, ...
1k views

### Is transmission wattage calculated using RMS?

I understand (and correct me if I'm wrong) that transmission power follows Ohm's law ($I = \frac{V}{R}$), that is that if I have a 50 Ω antenna that I know is transmitting at 1 W, then the current is: ...
1k views

### How do I build an portable FM transmitter?

I have been bugged with the idea of building a radio in a suitcase, but I have not many clues about where to start. My idea is to make a portable FM station so podcasts can be broadcasted in a small ...
2k views

### What is a linear RF amplifier?

Most of the RF amplifiers advertised, and most of the questions about amplifiers, are "linear" amplifiers. What is a linear amplifier, and what other common amplifier type(s) exist that requires ...
741 views

### What is morse code used for in amateur radio? [duplicate]

Ok , so I know very very little about amateur radio, I've hear in some websdr frequencies morse code transmissions and I've got quite curious, what are they? Who sends moresecode transmissions ...
21k views

### How to convert a Morse Code Message/QSO from Mp3 file into text?

I tried to use both: Cwget CW decoder But neither one worked. Can you recommend a tool or an alternative approach to decode a Morse message saved as an Mp3 file?
219 views

### What are contests? What do I need to know about them being new to ham radio?

I have heard about radio "contests" but I haven't seen a real explanation of what they are and what they entail. What do I need to know about contests before getting a technician license for the first ...
1k views

### How do I design a round or square coaxial transmission line to have a specific impedance?

Certain Hex Beam antennas use a coaxial center support post to send the RF to each antenna section, which is superior, in terms of maintenance, to a post with screw terminals connected by short ...
685 views

### What should I look for in an antenna for a DVBT Dongle used for SDR?

I use a cheap DVBT dongle that I control via RTL-SDR. Right now a very basic setup. The general consensus seems to be that a long usb cable should be used (to keep noise from the computer away from ...
4k views

### What are some good options for covert dual band vehicle antennas?

Would like to have a 50W mobile in my SUV, but I'm not allowed to have a big whip on the outside. What 2m/70cm dual band antennas are available that don't say, "Ham Radio Operator"? Are there three ...
326 views

### CW on phone band

In the U.S., regulations permit CW operations throughout the amateur bands. That makes the phone section of a band look tempting when the CW/digital part of the band is busy with a contest. I wonder ...
6k views

### Understanding coax impedance

I keep doing research, and trying to grasp it, but when it comes to RF impedances, and coax, I still have trouble trying to grasp it. So first, I think you have to have a 50 ohm coax for a 50 ohm ...
230 views

### How is the 10 m band performing now in January 2014? [closed]

I bought a 10m radio on eBay back in 2007 during the solar minimum when 10m propagation was nothing to write home about. I verified that the radio worked at that time, though it didn't seem to work ...
805 views

### How does aluminum siding on a house affect an inverted-vee antenna next to it?

My two-storey house is wood with alumninum siding. I had wanted to install an inverted-vee antenna with its midpoint hanging from the eave, and endpoints near the ground, but this would place the ...
59 views

### Testing a possible grounding point?

Some multi-story buildings in my region require earthquake isolation on some of the piping. Thus my question. Is there a way to determine whether a nearby metal water pipe is actually Earth grounded,...
902 views

### How many new amateur operators can currently use CW?

Given that it is no longer a license requirement, are there any current statistics available on what percentage of licensed amateur radio operators still learn Morse Code to some degree of proficiency?...
3k views

### What is the record for the highest non-automated over-the-air CW WPM speed?

Related to this question, but using humans, and in an actual QSO, not lab conditions: Is there a record for QSO QRQ speed? And, if so, what is the record for the highest non-automated over-the-air ...
170 views

### Measuring antenna characteristics without physical access?

There is a loop antenna that was thrown around an attic interior several decades ago, of long forgotten dimensions. I found the feed line. Is there a way to measure what (U.S. amateur) bands on ...
211 views

### Frequency Modulated Light

I've been doing a bit of work on optical open-air transmission, and have been thinking, any hays that varies the intensity of the light or whatever else would affect the amplitude. Would it be ...
181 views

### What advantages does SLA have over a Lithium chemistry battery for a Go Box?

Whether you refer to them as go-boxes, go-kits, or rapid deployment kits, powering a transportable ham shack is of utmost importance. While both battery chemistry types have much to recommend them in ...
2k views

### What is the definition of DX?

I always believed that DX meant out of one’s own country, and in the continental US that can be pretty far. However, tooling around on the bands I’ll often hear people calling DX inside the US receive ...
8k views

### How to detect common-mode currents or “RF in the shack”?

Let's say we already know that if your antenna is not suitably constructed or connected then you can get current on the shield of your coaxial feed line which will flow through the shielding/grounding ...
2k views

### What should I do if my call is being used by someone else?

I've been contacted by others who want to verify a DX with me, but I was not operating at that time! It appears that someone made several contacts using my callsign for a short window of time one day....
394 views

### The ARRL handbook updates yearly. Is it useful to buy it every year?

There seem to be updates to the ARRL handbook every year, but I don't know if the updates are significant or not. Is the yearly update minor, and buying a new one every 10 years would be enough to ...
2k views

### Best QRP HF band for small antenna?

What HF bands, times of day and/or conditions might be best for attempting to make non-local contacts using QRP transmitter power (around 1 Watt) and a small indoor folded or loop antenna?
4k views

### How would operating a ham radio affect other wireless devices in my house?

I am interested in getting into ham radio however one of my concerns is could a ham radio affect current wireless communications in my house. I am particularly concerned when it comes to WiFi signals. ...