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10
votes
1answer
498 views

Who funds amateur radio satellites?

I am currently studying for my Technician Exam and I am amazed at the sheer number of amateur radio satellites in orbit. Knowing how expensive it is to launch something into space, and assuming there ...
10
votes
3answers
4k 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 ...
10
votes
2answers
88 views

Where on the web can I find a calendar of upcoming contests?

For years, I have been using SM3CER Contest Service for HF contests. It is always good to have a backup, so I am looking for more or better. What do you recommend?
10
votes
2answers
143 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 ...
10
votes
6answers
2k views

While backpacking, is it worth mounting the antenna to the backpack frame (above my head)?

I am planning a trip with a large group in 6 weeks. We will be spread out in small groups on a trail in a mostly desert plateau landscape perhaps 5 miles apart, but mostly in a straight line. I'm new ...
10
votes
1answer
1k views

Why is dynamic range relevant for an SDR?

Sometimes I see dynamic range mentioned as a figure of merit for an SDR. For example, I know that the bits per sample used by the analog to digital converter can affect the dynamic range. Why do I ...
10
votes
2answers
3k views

How do I troubleshoot a Baofeng UV-5R that won't receive?

I have a couple of Baofeng UV-5R radios. I have a profile in Chirp that works great on one of them, and I foolishly pushed that profile straight over to a UV-5R without checking firmware versions. ...
10
votes
4answers
4k views

How do I find out what bands are open?

Say the deck is stacked. I'm out in the country with an all-band QRP home-brew rig, and an active antenna. Or say ship-wrecked and marooned on that desert island. The battery only has enough juice ...
10
votes
2answers
3k 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 ...
10
votes
3answers
367 views

Do I need to actually lock up my station?

Per §97.103, one is responsible for the proper operation of one's station, which of course includes that no unlicensed person uses it to transmit. I have heard suggestions (no link handy, sorry) of ...
10
votes
3answers
391 views

What is the best practice when tuning an antenna on air?

I have a magnetic loop antenna that takes a long time to tune and of course, while tuning it, I need to be transmitting. What is the best procedure for tuning on air? I understand I need to check ...
10
votes
2answers
612 views

Can an amateur use cellular technologies with SDR?

Software Defined Radio is opening up many new possibilities for amateur digital modes. One family of technologies that interests me is cellular. 2G GSM voice/sms and 2.5G GPRS data has been proven to ...
10
votes
2answers
2k views

Buddipole model comparison

Can anyone give me some insight into the different Buddipole models available? They look pretty similar to me except for the sizes. What would make you choose one over the other?
10
votes
3answers
398 views

Using MIMO in Amateur Radio?

MIMO, Multiple Input, Multiple Output, is used widely in commercial data transmission. 802.11n and LTE devices use it to increase throughput, link reliability, and channel usage without increasing ...
10
votes
2answers
996 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 ...
10
votes
2answers
241 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 ...
10
votes
4answers
1k 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 ...
10
votes
1answer
2k views

How does a “chip antenna” work?

How does a tiny surface-mount "chip antenna" for the 2.x thru 5.x GHz frequency bands work? What allows such a tiny item to radiate or receive RF with some amount of efficiency? What allows a chip ...
10
votes
2answers
690 views

What is meant by “poles” when discussing filters?

I was looking over the product page for the K3 (dreaming I know) and noticed that they offer a variety of crystal filters. Some are 5-pole and some are 8-pole, other than price, what is the ...
10
votes
2answers
596 views

Scoring quality of Morse Code “fist”?

When learning, teaching oneself, or training a class in Morse Code sending using a hand key, how can acceptable quality be scored (other than the letters being correct terms of dot-dash sequence)? ...
10
votes
1answer
1k views

What Part 97 rule allows unattended, automated transmissions, such as APRS weather stations and beacons?

What rule allows Amateur Operators to establish and operate remote, automated stations like APRS weather stations or beacons? Are there different rules specifically for beacons, or do they all fall ...
10
votes
1answer
2k 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 ...
10
votes
1answer
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 ...
10
votes
1answer
313 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 ...
10
votes
1answer
4k 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 ...
10
votes
1answer
879 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. ...
10
votes
5answers
443 views

Are there formulae to calculate capacitance and inductance of an antenna?

How to calculate internal impedance of a dipole antenna? Its resistance has two components ie wire resistance and radiation resistance, both these can be calculated using formula. Are there formula to ...
10
votes
1answer
129 views

Is there a special name (and if so what is it) for this flush-style SMA variant?

I have some radios that have a special antenna connector. It looks like an SMA connector, but the dielectric is flush with the end of the connector: rather than recessed the way "normal" SMA ...
10
votes
4answers
552 views

Why are commercial SDRs so limited in operating frequency?

I spent a bit of time researching SDRs, mostly looking into the possibility of building an all-FPGA-based TRX. There are a lot of commercial ready solutions; some are cheap, some not, but they all ...
10
votes
2answers
256 views

What is the most common amateur identification practice for mobile US amateurs operating in Canada?

When a US Amateur operates in Canada, IT and Canadian regs permit some lattitude on their identification. I have read that some will prefix a "VE3" plus their own home callsign (Ontario, meaning I am ...
10
votes
2answers
4k views

What is the expected microphone input voltage level of a handheld transceiver?

Ok, so I'm looking to inject some computer generated CW into a little handheld rig by wiring direct into the mic input line. What sort of voltage is expected on this input, are we talking uV, mV or ...
10
votes
3answers
395 views

Aside from repeaters, what station types allow automated transmissions?

I know repeaters don't have to have a control operator at the radio in order to transmit given certain conditions are met. Are there any restrictions to setting up automated stations which transmit ...
10
votes
1answer
208 views

What is body blocking, and does it work with a stock HT on a foxhunt?

I've heard that you might not need a special directional antenna to participate in a foxhunt, that some people are able to use their body to help determine the direction of a signal. How does this ...
10
votes
3answers
562 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 ...
10
votes
1answer
4k views

How to design a rubber ducky antenna

I am attempting to design an antenna for a 162.4 MHz omni receive only application and am confident it is going to be difficult if not impossible. I have very tight specs on space(6" diameter by 3" ...
10
votes
1answer
735 views

What does a lightning bolt symbol next to an antenna connector mean?

On the back of my Yaesu FT-897, next to each of the antenna connectors, there are lightning-bolt-ish symbols. What do these mean, and is there something I ought to be doing because of that? I have ...
10
votes
4answers
893 views

How does an antenna transform impedances along its length?

If I insert some impedance (like a loading coil, or a trap) at the base of a monopole antenna, the effect on the feedpoint impedance is easy to predict: the impedance is in series with the antenna, so ...
9
votes
6answers
26k views

What is a Gamma match in the context of the driven element of a Yagi antenna?

How (and why) does a Gamma match work, when used on the driven element of a Yagi antenna? As shown here: (source: http://www.iw5edi.com/ham-radio/?2-element-yagi-for-10-meters-band,49) The article ...
9
votes
2answers
2k views

Is Morse code allowed on FM in the USA

Let's say I get my little 2 meter FM handheld out and make a little sine-wave generator with which I pulse a morse code and if I connect it to headphones a speaker, I hear the dits and dahs of a nice ...
9
votes
5answers
25k views

Is there a simple, DIY, antenna suitable for HF receive only?

So the antenna I'm thinking about doing might be* way too large for my property. Is there another simple, cheap, DIY antenna I could try on my receiver? I know I'm going to want to hook it up and ...
9
votes
5answers
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 ...
9
votes
4answers
31k views

What is the difference between channel & frequency & band in RF?

I am reading about wireless networks basics. I found three terms I cannot find exact definition for: channel, frequency band, frequency. Can anyone give exact definitions for them?
9
votes
3answers
6k views

What is the effect of using different number of radials with ground plane antenna

I'm new to electronics and telecommunication at all, I having trouble with understanding the difference between 2, 3 and 4 radials, as I've searched online I've learned that I can use only 1 radial(...
9
votes
4answers
333 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 ...
9
votes
2answers
380 views

Why do we have to hand wind toroids?

Many, if not most, ham radio kits (transceivers, tuners, ununs, baluns) require the builder to hand wind and tap their own toroids. (example) This is a considerable area of stress for newbie builders ...
9
votes
6answers
5k views

What is the impedance of an end-fed half-wave antenna?

It is my understanding that the feed-point impedance ($Z_a$) of an end-fed half-wave antenna is dependent on at least the following factors: $L_a$: The length of the radiating element of the antenna. ...
9
votes
2answers
2k views

Can every antenna be used both for transmit and receive?

Assuming I have an antenna for receiving GPS signals, can I use it also for transmit — to create a repeater in a tunnel (or some place with no reception)?
9
votes
5answers
315 views

Does an amateur radio licence work worldwide? [closed]

Lets say that I get my amateur radio license in country A and then some time later I move to country B. Will I need to get a new license on country B or does the license obtained in country A works ...
9
votes
3answers
3k views

Why do so many HF transceivers use a UHF connector?

Just looking around at various rigs online for a fiend. Lots of them look really attractive TS-480, K2, K3, FT-450D, FT-950, IC-78, FT-897 to name just a few... These rigs are mostly HF, albeit some ...
9
votes
4answers
3k views

Can I operate in the United Kingdom with a US license?

Can my license from the United States be used to operate while I'm in the United Kingdom?

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