# All Questions

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23k views

### Calculating Antenna Length on the FCC Exam vs. in Reality

I have seen the following formulas for calculating half and quarter wavelength antennas: Formula for $\frac{1}{2}$-wavelength antenna (in free space): \mathrm{Length~(feet)} = \frac{...
2k views

### Is is possible to operate D-Star from a software-defined radio?

What is preventing a software-defined radio from transmitting the D-Star protocol?
21k 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?
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 ...
973 views

### Can I transmit anything inside a Faraday cage?

Can I perform any transmission regardless of my license as long as I'm inside an RF sealed enclosure, such that no RF will be detectable from my transmissions off my property? I imagine the answer is ...
3k views

### How can I add amplitude modulation to this transmitter?

I recently built this circuit, and could hear a nice full quieting signal on my short-wave radio with a 7.2 megahertz crystal for the 40 meter band. What is the simplest way I could Amplitude ...
10k views

### How To Join Packet Radio BBS

I'm a complete newbie here, and on the Southeast Coast of the USA. I don't even own a ham radio yet. Some preppers and I got to talking about a dystopian time of Internet collapse where shortwave ...
514 views

### What are the relative bandwidths of the amateur bands?

While I was operating on 40 m for Field Day, I noticed a higher SWR than when I first set my antenna tuner for the band. This happened, of course, because I was in a different part of the band, but I ...
1k views

### What is generally considered “too much” power for JT-65 on HF?

Recently, I have begun experimenting with JT-65A, mostly on 20 meters. I usually run about 5 watts with that mode, since I know that JT-65 is a weak-signal mode. Is that still too much power? What is ...
1k views

### Direction finding: How to find a stuck FM transmitter on 70cm?

There's a blank carrier on a 433 MHz FM voice frequency here. How should we go on about finding the transmitter's location? Practical procedure? Could be somewhere downtown.
6k views

### How is the IF for a superhet selected?

There seem to be almost as many choices for the intermediate frequency (IF) as there are superheterodyne receivers and transceivers out there. The ones I have come across are 455 kHz, 452 kHz, 1.6 MHz ...
1k views

### Amateur radio in an EOC?

Consider a small town's emergency operations center. While there are amateur radio operators involved, they primarily work for government or public safety, and there is no active ARES participation. ...
230 views

### Do volunteer exam coordinators provide accommodations for applicants with visual impairments?

I am a prospective HAM, and I recently began reading the ARRL's third edition of their Ham License Manual, published in 2014. Anyhow, under WHO CAN BE A HAM ...
4k views

### Share antenna between receiver and transceiver?

I recently put up a fan dipole for 80/40/20/10. I'm looking for a way to share this antenna with a receive-only SDR and my shack transceiver. Obviously I can just switch this antenna between the two ...
662 views

It is common wisdom that transmissions of any sort (perhaps unidentified, encrypted, in the FM broadcast band, etc.) are permitted if they are sufficiently low power. Where are the FCC regulations ...
8k views

### Protect rig from static charge on antenna

How can I continuously discharge static from my end-fed antenna? My Electraft K2/100's autotuner (schematics) has an SWR bridge using two 1N5711 pin diodes. These diodes get blown if any static ...
579 views

### What is the role of digital data modes in emergency communications?

Emergency operations are typically reliant on voice traffic today. Are digital data modes used at all in emergency operations, and why/ why not? Couldn't data modes be used to pass information more ...
9k views

### Where are the baluns for VHF and higher? How can one be made?

In another question, commenters recommended that I look into adding a 1:1 balun to a dual-band dipole to eliminate the feedline as a radiator. As I understand it, a 1:1 balun also functions as a choke,...
570 views

### Is there a KML or similar file that shows all of the CQ Zones?

I'm wanting to view the CQ Zones in Google Earth, and I understand that a KML file will allow me to do so. Is there a place where I can get a KML file that shows all of the CQ Zones?
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 ...
561 views

### Calling a friend on simplex

Can someone please help clarify. I have tried searching all over, but almost all of the examples you find online and in books are for calling CQ on HF. I am new to ham radio, and recently got a few of ...
2k views

### Are antennas circuits?

For an antenna to work, doesn’t charge have to flow through it? A current must be present. To me it indicates it must be a circuit, but how is a dipole a circuit? If they are not circuits, then how ...
232 views

### How do I increase my phone intelligibility?

Listening to various operators at different times, I've sometimes noticed, especially during contests, that some operators are easier to understand than others, and it doesn't all seem to be due to ...
4k views

### How to reduce RF in the shack when using vertical HF antenna (no radials)

What can be done to reduce RF in the shack (riding back along the coax) when using a vertical 10M antenna (without radials due to space constraints)? The antenna is an IMax-2000 at 32' elevation (20' ...
921 views

### What does a SSB frequency actually indicate?

An SSB signal is an AM signal with the carrier and other sideband filtered out, if I understand correctly. As such, when specifying an SSB frequency do you specify the carrier frequency, then state ...
5k views

### What is the best time of day/Band to make a contact with Hawaii from the East Coast?

I need to get Hawaii for Worked All States, and live on the East Coast (Virginia). Furthermore, I have a poor antenna, and thus only the prime times of the day seem to really be opened for me. What ...
2k views

### Why can't I hear myself from a second radio when bouncing off a repeater?

I am a relatively new ham, and haven't joined any club yet or participated in any nets. I have, however, hit a repeater just to know I can do it. I was told my sound was scratchy (no surprise there) ...
511 views

I stayed at a resort in the U.S. recently that is located in an unpopulated area with virtually no radio reception. To fill the gap, the resort has its own FM station that can be heard only within ...
193 views

### What skills will I learn from contesting?

I got into Amateur Radio for emergency preparation and to allow me to expand my electronics hobby. My needs are being met, but I'm wondering if I'm missing out on increasing my skills by avoiding ...
262 views

### Why do satellites receive and transmit on different bands?

Most satellites I've found transmit on VHF and receive on UHF or vice versa. Why is this? I would think there's enough space on a single band.
5k views

### What do the three-letter modulation codes (emission designators) stand for?

I've seen these weird three-letter modulation codes like J3E, A3F, A1A, F3E and so on. Someone even wrote 2K40J3E or 12K5F3E. What do these codes stand for?
5k views

### Conductive boom vs non conductive boom: what's the difference on a Yagi?

I designed a Yagi antenna using 4nec2, assuming that I would use a non conductive boom. If I use an aluminum boom but I insulate the elements from the boom, can I keep the same design? How does it ...
477 views

### Key CW on zero crossings - zero bandwidth?

I remember being surprised to learn that a CW signal has a bandwidth (albeit small), but when I thought it over, it made sense. Essentially, we are modulating the carrier with a low frequency square ...
5k views

### How is “clarifier” control helpful?

My radio-club recently got a Yaesu FT-225RD transceiver and I'm trying to digest its manual (available for download here). This is the first ham radio that I'm learning how to use, so I could be ...
2k views

### Does iron ore in the ground affect my signal?

Mineral content in the ground varies from one place to another. I've visited places where the ground & waters were an orange-red shade from the high iron content; not good for trees either. This ...
662 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 ...
868 views

### Is “low loss” cable required for HF?

I use RG-58 for all my HF antennas, since it's light, flexible, convenient, and cheap. And super easy to choke. Whenever I have a problem I just loop a few turns of it on a ferrite core and the ...
371 views

### What kind of antenna is that one?

Yesterday I saw the following antenna: I am very puzzled, at first glance it seems a simple dish but: The mesh is really wide (low frequency?). It is pointing to Zenith. I think that most dish ...
5k views

### How do I renew my FCC amateur license?

I have a technician class license, and my license expires in March 2014. How do I renew my license? I received a notification in the mail from W5YI-VEC informing me that I could renew my license ...
2k views

### Capacitive hats on wire dipoles?

Capacitive hats seem to be advertised as an option for mobile vertical antennas. One mentioned advantage is the they can widen the SWR bandwidth, making the antenna easier to tune. What might be the ...
4k views

### Is there an optimum Antenna Feedline Length for mobile installations?

I bought a ham radio antenna mounting kit for my car that includes ~16' of coax. One end has a trunk lip NMO antenna mount, the other end has a re-solderable PL-259. I asked the sales person if it is ...
885 views

### How can I participate on Echolink with my Android phone?

I want to use my Android mobile phone to send and receive over Echolink, like if I was using an amateur radio station. How can I do that? I'm a SWL and only plan to listen until I get my license, and ...
331 views

### What would propagation look like on Mars?

If we could get a few HF stations on Mars, what would the propagation look like? Thought shamelessly copied from this blog.
5k views

### Is it legal for a non-profit to use ham radios for emergency purposes?

I've been tasked to help update my organization's emergency contingencies and ham radios were brought up. We provide residential services to the mentally handicapped and we are looking at ways to make ...
7k views

### Are Baofeng radios illegal in the U.S?

Having a low price budget, my search for my first ham radio to buy has led me towards Baofeng. A quick Google search on baofeng showed a lot of results that said that certain model baofeng handhelds ...
1k views

### Will electrically joined dipoles of different lengths, at right angles, behave as a multiband antenna?

I haven't seen this done, (which, after more than a century of amateur and professional radio development, is probably a bad sign), but I had an idea the other day for simplifying the setup and feed ...
371 views

### Is use of the phonetic alphabet mandatory?

The phonetic alphabet is often used on amateur radio to spell out names and callsigns more clearly, especially when the clarity may be poorer. However, there are cases where I simply forget certain ...
936 views

### What is the highest US amateur license I can get in one sitting?

If I start with no current license, can I take all the exams in one sitting to get to Amateur Extra?