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2
votes
2answers
107 views

Whats wrong with this radio signal?

I have a code that sends a beacon every 1 minute with a data-rate of 1200bps (BPSK-G3RUH). I do receive the signal using a custom software defined ground station that also decodes the beacon. After a ...
0
votes
2answers
99 views

Imaging with radio Frequency

Is it possible to image bones and tissues with radio waves (2.7GHz-5GHz) with a tiny radio frequency source and on one side and a receiver on other side which can image the data through a PC mediated ...
1
vote
4answers
136 views

Indoor HF/VHF/UHF antenna, have someone an Idea?

My wife doesn't think that having tall antennas is acceptable. Does anyone have a solution for this? Our house is 16 meter long and 10 meter wide. I have an antenna tuner (if it can help).
1
vote
1answer
66 views

Can Yaesu FT-65 be charged from a 12 VDC automotive accessory outlet?

I recently purchased a Yaesu FT-65 handheld radio and quickly discovered it had no 12 VDC power port like other handheld radios I've seen. The charging cradle uses a 12 VDC wall wart for power, and ...
1
vote
1answer
37 views

PSR500/Pro106/WS1040 Phase II Upgrade?

I want to know if one can upgrade the hardware chips/ the CPU/DSP inside police scanners to do Phase II. I know they cannot do Phase II due to hardware/software limits but if whistler can upgrade ...
10
votes
3answers
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 ...
2
votes
1answer
45 views

How Do Ground-Mounted Verticals Compare to Elevated Verticals? [duplicate]

Their performance differences may be less than sometimes expected.
5
votes
1answer
130 views

Looking for a book that contained a circuit for receiving (literally) underground amateur radio transmissions

In this comment in Earth Science SE I've said: This is a really cool question! I remember (a long time ago) reading about electromagnetic waves inside conductive soil that travelled near but below ...
1
vote
1answer
71 views

144Hz monitor with freesync noise on 40m

When I tune on 40 m (7.074 MHz USB as test frequency for there's FT8) and turn on my PC with a monitor that's 144 Hz refresh rate and has freesync on, it starts to make noise and makes signals almost ...
3
votes
2answers
108 views

HDMI to VGA adapter interference with 138.5 MHz carrier

(sorry for my English) I'm using the HDMI to VGA adapter on my pc, and receiving weather satellites on ~137 MHz with RTL-SDR V3. There was a problem: my VGA adapter creates a powerful signal, who ...
5
votes
3answers
109 views

APT/LRPT images geotagging

I want to extend functionality of some open-source programs which decode APT and LRPT images (wxapt and glrpt). More specifically I want to add possibility to overlay geographical data such as land ...
3
votes
1answer
76 views

How proper HIHI sounds like?

Recently I've read Zen And The Art Of Radiotelegraphy by Carlo Consoli, IK0YGJ. I must say, it's a great book, and as a new CW operator I've found plenty of useful information in it. What especially ...
7
votes
5answers
119 views

I can copy 15wpm how to to continue?

I solely learned to copy cw via a computer program using the Koch - method (http://f6dqm.free.fr/soft/cwplayer/en/cwplayer.htm) I never learned how to send and if it is no big disadvantage, I would ...
4
votes
1answer
165 views

Identification of valve

My favorite receiver used for 40 m AM broadcasts has a cracked valve, but the valve type normally printed on the glass has rubbed away. Can anyone tell me what the numbers for this valve are ? The ...
3
votes
1answer
51 views

2 meter and 70cm OSCAR expected signal attenuation by topocentric elevation angle, chart?

On average, is there a chart, or formula, which shows an expected signal attenuation due to the elevation angle to the satellite's position? I understand that range (distance) is also going to affect ...
5
votes
1answer
97 views

Demodulation based on external frequency source

I saw a design for a walkie talkie that used a mixer that mixed the TX freq to the RX path before demod. Looking at the SA616 chip, demod is acomplished by Gilbert cell quadrature detector that is ...
2
votes
2answers
119 views

Short low dipole, better if horizontal or vertical?

Say I have a shortened HF dipole (with significant inductive loading and/or capacitive hats), and can only mount it very close to ground level (but not touching), over lossy ground, and with no ...
0
votes
1answer
118 views

Where am i supposed to ground the audio path?

Where does the ground of the audio path go in this schematic?
7
votes
3answers
2k views

Can a 1:1 transformer be used as a protection from static electricity?

It's well-known that under certain conditions verticals and dipoles can gather static charge, which is a common reason of transceiver damage. There are several ways to solve this issue. Some hams ...
3
votes
0answers
83 views

9:1 unun material and power loss

I need to build another 9:1 unun and I start searching for my toroids... (I have build 2-3 something like 4 years ago)... In parallel I checked on Google about the correct toroid etc so I found 2-3 ...
9
votes
0answers
64 views

How do Radio Regulations and Frequency Allocations Apply to an Ionosonde?

An ionosonde is a special HF radio transmitter that periodically transmits a signal that sweeps across a large portion or the entire HF spectrum to identify the propagation of radio signal in the ...
3
votes
2answers
77 views

4:1 Balun question

With an OCF dipole, does it matter which leg, short or long, is connected to which side of the 4:1 balun, hot(coax center) or shield? How can you tell which is which, the balun is not marked. Thank ...
2
votes
2answers
80 views

Estimating near-field electric field strength at LF (137 kHz)

I'm experimenting with low frequencies, but due to the inherent nature of LF, I strive for more transmit power and bigger antennas. Now of course I want to comply with regulations, which allow (in my ...
2
votes
1answer
117 views

Which is Better to Use with Vertical Monopoles: Buried Radials or Ground Screens?

Many threads posted on various websites over the years have included statements/beliefs on this subject, but support there for the accuracy of those statements sometimes is minimal. An accurate ...
4
votes
2answers
98 views

Why isn't some form of twinax commonly used for antenna feed lines?

Twinax (shielded controlled impedance balanced line pairs) is said to be used in 10G ethernet signaling for greater noise immunity that other cabling types. Why isn't twinax (or similar) commonly ...
7
votes
5answers
167 views

Coax fed dipole: shield goes to one side, yet is grounded via chassis line to Earth

Suppose I have a coax-fed half-wave dipole antenna. The coax shield goes to one side of the antenna, the center conductor to the other side. The transceiver's chassis is connected (via the coax ...
4
votes
1answer
139 views

Yaesu FT-991A: FM and C4FM modes don't work on HF bands

I bought a second-hand Yaesu FT-991A. It works pretty well and by the look of it's internals I don't believe it was ever repaired. However I noticed one weird thing. When I try to use FM or C4FM on ...
1
vote
1answer
44 views

Vertical Hustler - do I need any radials?

I'm planning on installing a Hustler 4-BTV vertical by the house. There's already a 12 ft. steel pole mounted in cement, so I'm going to mount it on that pole about 10 feet up (sort of small mini ...
1
vote
1answer
53 views

Info on this Bunnell J-38 key

I've been trying to find manufacturing date info on the J.H. Bunnell key ("J.H. Bunnell&Co" is stamped on top of the frame), but it seems to be somewhat unique. Most J-38 keys that I've found ...
1
vote
1answer
102 views

General Vs Technician Call Sign?

Is there a distinction between a call sign for a General vs. Technician? I recently upgraded to general, I am curious about changing call sign to reflect license upgrade?
1
vote
2answers
70 views

Vertical antenna

I'm installing a vertical antenna in back yard. About 20 feet in height and using 1 counterpoise wire 16 feet for 20 meters. Does installing two or more counterpoise wires help?
1
vote
2answers
81 views

What is Logbook Of The World or LOTW?

An answer to this question on QSL cards refers to something called Logbook Of The World or LOTW. What is LOTW? What is its history? What problem does LOTW solve? (that isn't solved by plain QSL ...
3
votes
3answers
158 views

Calculation of transceiver current draw

My radio manual says its current draw is 22A. But in my naivety I would have calculated as follows: If the radio 'put out' 100W and I have a 13.8V supply then (using the formula power = VxI) 100W/13....
5
votes
2answers
105 views

What is a QSL card?

What is a QSL card? Why would I ever receive one? Why would I ever bother to send one? If so, when? Is it rude not to? Are they postcards sent by physical postal mail, or are they now digital ...
2
votes
1answer
66 views

Looking for headset to use with BTech UV-25x2

I have a BTech UV-25x2 that I'm using as a portable base station. This radio has a "TRRS" connection (GND/SP/MIC/PTT) which I would like to get a headset for. I'm relatively new to ham radio, so don't ...
0
votes
1answer
82 views

Baofeng UV-82 and DM-860 drivers Windows 7

Currently I'm trying to make my radios (Baofeng UV-82 and Baofeng DM-860) friends with my Windows 7 and Chirp. My computer has only USB ports and no COM; Google adviced the Profilic driver (PL2303/...
1
vote
2answers
103 views

What is NR and a number instead of city and state after my QTH?

I have been a ham for almost 20 years, and when on CW I have always sent my call, name, RST, and full QTH. I have noticed that now many operators send NR 5280 or something similar instead of their ...
-3
votes
1answer
45 views

Can the power output of a software defined radio be adjusted? [closed]

Some SDR transmitters have a very low power output. Can their output be adjusted?
5
votes
2answers
163 views

Looking for a schematic of a DIY circulator

I would like to build a simple HF, VHF or UHF circulator to get a better understanding of how these devices work. Sadly at the moment I'm unaware of any articles or books that provide corresponding ...
3
votes
2answers
279 views

How to determine frequency and launch angle given a target skip distance?

I would like to communicate with someone 1000 miles (1600 km) away. I'm not sure how to target a specific distance. (image source) I assume it's an interrelation of the following factors: Which ...
1
vote
1answer
97 views

ZS6BKW deaf on all bands except 40

I have purchased a high quality ZS6BKW from the U.K. I have it suspended up about 40' between 2 trees. There is 30' of coax from the ladder line to the radio (Kenwood TS-870).SWR on the MFJ269 shows ...
1
vote
1answer
54 views

Squelch won't stay open on FM 2 meter band

I am currently using a Baofeng BF-F9V2+ radio. I have found the when listening, my squelch won't stay open, despite getting a good clean signal. I am using a homemade verticle dipole antenna for 2-...
0
votes
2answers
95 views

Is there a way to find the direction of a vehicle using radio?

I was wondering If I could use an Arduino to find the direction of a vehicle using radio. I want the Arduino to find the orientation of the radio/where the object is detected (North, South, East, West)...
4
votes
1answer
83 views

What gain and power are required for successful DX contacts on 2m/70cm bands in CW?

I would like to practice in CW on 2m/70cm bands when and if there will be a tropospheric or sporadic-E propagation. However I don't have mush space for the antenna. There is a possibility to install 3+...
4
votes
1answer
200 views

Is a ground plane antenna a poor choice to use in a forest?

Some time ago, when I just started with amateur radio, a few more experienced hams told me that an inverted-V works better in the forest than a ground plane, and that it has something to do with the ...
0
votes
2answers
109 views

sdr as watts and amps [closed]

Thanks to rclocher3 for helping edit more to English why closed so my struggle to get thought to English thank rclocher3 I round back too best I put in avuenue what I was asking why closed i tryed ...
1
vote
3answers
119 views

SDR transmit on more than one frequency

I'm new to SDR. Is it possible to transmit on more than one frequency, and if so what do I need? more on computer type network side one for each 800, 2.4, 5, 60 How can I get more than one SDR to ...
1
vote
0answers
30 views

power limit on wireless FM microphone transmitters [duplicate]

I am building a "toy" radio station as a teaching tool for high school students to work with. I intend to use a small (short-range) wireless FM microphone module as the transmitter. What is the legal ...
1
vote
1answer
72 views

Receiving different gain values on two RX channels on Ettus USRP B210

I am transmitting a continuous wave and using one USRP B210 with the kitchen_sink tool in order to save the received samples from two RX channels (v.3.15.0) When I look into the received signal on ...
9
votes
2answers
1k views

Who enacts the FCC's rules and regulations?

I came across an old answer on this site which makes the claim: It would take an act of Congress to change this [FCC Part 97] rule. Is that correct? I was under the impression that United States ...

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