# All Questions

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2k views

### When may a ham operate beyond the privileges of their licence class?

As far as I know, all radio amateurs are assigned privileges on Power Output Mode of operation Operating bands as a function of the class of licence they hold. These privileges differ from one ...
599 views

### Why do concurrent FM signals not mix together?

Generally when I hear two conflicting signals they do not mix together, but rather one dominates then the other. This phenomenon can be observed on FM broadcast station when driving out of range from ...
6k views

### Is there a way to listen to live HF communications using the internet?

I'd like to be able to show people what a QSO sounds like without having my transceiver available. Is there a way I can listen to amateurs talking in real-time (or using Morse code) on the HF bands ...
332 views

### Why is the speed of light rounded to 286 Mm in calculations involving frequencies below 30MHz?

I understand that in order to make the maths simpler, frequency ($f$) is expressed in megahertz (MHz) and the velocity of propagation in free space ($c$) for frequencies above 30 MHz is expressed as ...
769 views

### What gain do I need to talk to SO-50 with my HT?

My HT has 5 W of power, a sensitivity of about 0.2 µV, and I would like to talk to the SO-50 with it. How much gain do I need in my antenna to make this work?
5k views

### How do I discover APRS coverage?

I'm considering adding simple APRS transmitters to my vehicles. I'd rather just put one in and forget about it, but I understand there are areas of the US where a stronger transmitter would be ...
205 views

### What are amateur radio bands? [closed]

I'm new to radio and would like to know what amateur radio bands are. I'm also wondering about the range of these bands/how many there are.
1k views

### Why do Amateur Radio organizations in the United States oppose the relaxation of encryption prohibitions?

I saw this question stating that it is illegal to encrypt traffic, at least in the US and UK. I also heard that there was recently an attempt to get the FCC to loosen this restriction, but a lot of ...
8k views

### What does Ham mean?

Amateur radio operators are always referred to as Hams, it's basically the most common term for the hobby, at least around here. Where does the term come from? I heard that it's an acronym for ...
2k views

### How can I prevent my mobile radio from draining my vehicle's battery?

I'm a very absentminded ham. I have a radio mounted in my car, wired directly to the vehicle battery. Fuses and high-gauge wire and all that good stuff. But, if I accidentally leave it on, my battery ...
9k views

### How do I power my radio in a vehicle mobile install?

I want to install a 30W mobile UHF radio in my car. I already have an antenna and mounting bracket - but how do I get power to this radio? It has an SAE bullet connector on the back - do I just need a ...
1k views

### Can I have multiple inverted-vee antenna fed by a single coax?

A friend who recently received his call is planning to setup an inverted-vee for 40/20m bands. Our take is the signal will take the path of least impedance into the correct length antenna wire. ...
716 views

### Why is an exemption for music given to NASA broadcasts of manned space flight missions?

FCC 97.113 Prohibited transmissions reads: (e) No station shall retransmit programs or signals emanating from any type of radio station other than an amateur station, except propagation and ...
367 views

4k views

### How to calculate the peak-to-peak voltage of a sine wave given RMS voltage

How do I calculate the peak-to-peak voltage of a sine wave given RMS voltage?
75 views

### When and how do I use a Smith chart? [closed]

What are some real-world problems that a Smith chart can help me solve? Ultimately I'd like to gain a more intuitive understanding of the space the chart represents, but it seems to me that actual, ...
1k views

### Why is the solar-flux index measured at 10.7 cm?

Why is the solar-flux index measured at 10.7 cm? What makes that such a special frequency?
8k views

### How to find the front-to-back ratio given an antenna radiation pattern diagram?

I know that the front-to-back ratio is 18dB in the below antenna radiation pattern diagram, but I don't know how to read the diagram to obtain this result. How does one read and understand such ...
122 views

### Model of a specific DVB-T tuner chip (circa 2013) that can be used to collect raw IQ samples

There is a common DVB-T receiver chip capable of producing raw IQ samples, which makes it a good device for Amateur Radio SDR experimentation. The chips is used in some DVB-T USB dongles sold around ...
1k views

### Where can I find the official definition of ITU Zones?

I've been looking around for a spot that has the official definition of what the various ITU Zones are, but can't find one. What is the official definition? I'm hoping for more than just a map, unless ...
4k views

### Can I listen to hams on a standard AM/FM broadcast receiver?

I am very much out of practice with amateur radio (like many others), so to some, this question may seem obvious. I don't have any specialised amateur radio equipment, but I do have a Sanyo AM/FM ...
59 views

### What are some fun activities hams participate in? [closed]

Yes, Amateur radio is a hobby. The general impression however is that it is a geeky/nerdy/kooky (I forget which carries a negative connotation!) hobby; either the ham sits at a transceiver, or is ...
253 views

### Which qualities/features does an SDR radio device need to be usable for Amateur Radio?

I know what things to note when selecting an analog amateur radio, but SDR devices have completely different specs, e.g. sample rate and resolution. What do I need to know about the device to make ...
6k views

### Phasing harness for antenna array

I understand that certain antenna designs (particularly phased arrays) require feeding each radiating element with a certain number of degrees of phase separation in order to achieve a desired ...
399 views

### Getting Started with APRS [closed]

The APRS.org web site provides some good information but is not very well organized and does not appear to be actively maintained. What are some good resources for beginners seeking the following: ...
172 views

### How is ARES different from RACES?

Just what the title states. Here, in India, in the context of public service we hear of RACES (Radio Amateur Civil Emergency Service). I recently learnt about something called ARES in a similar ...
321 views

### How is a “Generally Inactive” ham determined for Field Day GOTA?

ARRL Field Day Rules allow a GOTA station to be operated by "a generally inactive licensee. " There are members of my club which started to become active again after a long term of inactivity a few ...
17k views

### How can one convert from Lat/Long to Grid Square?

I see that many contests, awards, and other items, use Grid Squares as a means to identify where one is. How can one figure out what one's grid square is, given lat/long?
3k views

### OK to use any repeater?

There are a number of repeaters in my area, each belonging to a particular amateur radio club. These guys are all friendly and willing to chat but I was wondering if it was bad form to make use of a ...
2k views

### Practical 80m vertical wire antennas without radials?

We'd like to install an antenna for 80m at our club/contest station. Our club, OH2K, is housed at a school, and we can't fill the roof with a radial mesh. The roof is not metallic itself, either. We ...
110 views

### Interference generated by antenna placement?

I'm thinking about putting up a 80m dipole in the back yard, the only place I have to put this (can't do inverted V since I don't have a high enough location) is close to a overhead telephone wire. ...
595 views

### How to Evaluate Antenna Data

I found some data on antennas that had been tested for a specific radio. I'm trying to decipher what this data means and how one would go about gathering it. Are there any good resource for learning ...
164 views

### What regulatory issues/differences should I be aware of as a US ham vacationing in Europe (Poland)?

I am a US ham with an Extra Class ticket. If I were to go Poland (or possibly some other part of Europe) on vacation and bring some radios, what legal stuff do I need to know about? I know that my ...
95 views

### HSMM problems introduced by mismatched antenna feed points

I have been trying to understand the finer points of HSMM, and I ran across this statement about antenna feed points (emphasis mine): 802.11 signals produce very broadband signals, typically 20-22 ...
23k views

### What do “QRM” and “QSB” refer to?

An answer on Basic QSO format? mentions things like "QRM" and "QSB". What do those terms mean?
1k views

### Is there a way to modify my Yaesu FT-60 to transmit on all 4 ham bands it can receive?

I have a Yaesu FT-60, and it can transmit on 2m, 70cm, and receive 1.25m and 33cm bands. I would really like to find a way to get it to transmit on 1.25 and 33cm. Is there a way to make this happen?
1k views

### AIS and RTL-SDR Dongles

I am looking for an Windows-based AIS Decoder for RTL Dongles. Currently, there is a solution available using GNU Radio and SDR# but it is complicated to set up and keep running. ADSB has a dedicated ...
463 views

### Secure communication over Amateur-band HSMM / 802.11 in the United States

I'm quite interested in 802.11 over amateur radio frequencies; however, all I have done at this point is reading (I don't have a ham license yet). The conventional wisdom (espoused in this ham.SE ...
464 views

### What's the purpose of a soundcard in digital communication?

If I get involved in digital communications do I need to buy a soundcard? If so, why, what does it do?
1k views

### Basic QSO format? [closed]

What is the basic format for a QSO? How should I answer to "CQ", how do I know when it is my turn to answer, when should I give the report, etc.?
481 views

### Is a Technician license enough to assist in times of emergency?

Is a Technician license enough to assist in times of disaster/emergency or do I need General or higher?
227 views

### Can I modify my radio to transmit on frequencies that I can currently only listen to? [closed]

I bought a radio that can receive 4 ham bands, but only transmit on 2. Can I modify my radio to transmit on these frequencies legally?
30k views

### Should I chose a vertical or a horizontal HF antenna?

If I only have the budget for one HF antenna, should I chose a vertical or a horizontal antenna?
98 views

### Can wood be used to build 6m quad? [closed]

Could I use wood to build 6m quad? If not, what material(s) would be better/more useful?
3k views

### Pros/cons of the PL259/SO239 connector (M type)?

What are the pros/cons of the PL259/SO239 connector (M type), and why is it used preferentially on civilian rigs vs military?
382 views

### How do I determine antenna spacing?

How do I determine antenna spacing so that I don't end up overdriving the front end of a receiver when transmitting?