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3
votes
1answer
22 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 ...
1
vote
0answers
20 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 ...
6
votes
0answers
19 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
1answer
30 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
43 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
85 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 ...
3
votes
2answers
61 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 ...
4
votes
3answers
52 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
47 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
32 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
0answers
25 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 ...
0
votes
1answer
56 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
59 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
49 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 ...
2
votes
2answers
112 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....
4
votes
1answer
65 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
23 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
26 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
85 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
35 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
113 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 ...
2
votes
2answers
149 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
57 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
45 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
0answers
11 views

Transistor cross reference with pinout [migrated]

I need to find a replacement transistor. The only number I have to go by is a manufacturer (of the unit, not the transistor) part number from 1974 which of course leads nowhere. I know it's a ...
0
votes
2answers
89 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
64 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
182 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
93 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
103 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
29 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
60 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 ...
4
votes
0answers
56 views

Commercial Loopstick Antenna Manufacturers

Not sure this is the right forum for this but I thought I'd give it a shot. I am an electrical engineer working on a product that needs a loopstick antenna. I had thought that AM radios were so ...
0
votes
0answers
36 views

how do you tune blind? [duplicate]

I'm about to axe the display on my radio in pursuit of cheapness. However, I need to know, how do blind hams with older rigs tune to a station?
0
votes
1answer
62 views

How should I stack these folded dipoles?

Looking to stack these 8 folded dipoles on my 100ft tower. I can not find any information whatsoever on these. I have 4 consecutive serial numbered boxes. Bluewave Marathon BME139FN1H0 138 - ...
1
vote
1answer
55 views

Can I get non demodulate IQ signals from WebSDR

I want to take a non demodulate audio signal from webSDR portals (http://www.websdr.org/). In order to try to feed these in DREAM DRM Radio software or GNURADIO. Could be cool almost try it for ...
5
votes
1answer
50 views

Do External Signals Affect Antenna S11/SWR Measurement?

Do external signals affect the S11/SWR measurement of an antenna? For example, if I try measuring the S11/SWR of an HF antenna with a SWR meter or a Vector Network Analyzer in the middle of a field ...
1
vote
2answers
60 views

Advantages of IQ mixer versus baseband sampling SDR architectures?

What might be the advantages, if any, of HF SDR architectures that use a mixer between the ADC/DAC and RF, versus those that sample or generate RF directly at baseband with a fast ADC or DAC? Are the ...
2
votes
3answers
246 views

What causes my direct conversion 80m receiver to receive AM broadcasts?

I am making a Direct conversion receiver from this circuit at this website. I made it for the 80m band and I changed: The frequency of VFO to about 1.75 MHz L1 and L2 to a bandpass filter for 80m ...
0
votes
1answer
37 views

How to identify type of modulation from recording done by gqrx or gnu radio?

Is there a tool or some other way that would allow me to find out the type of modulation of a specific signal? What I specifically try to do is to decode signal from this remote control: http://www....
1
vote
1answer
47 views

How is gqrx producing audio?

How exactly is GQRX converting signal in any frequency to produce audio output? Is it actually done by gqrx or some other element of the stack?
0
votes
0answers
11 views

RF signal Multiplier or Chopper [migrated]

I'm trying to design a circuit that "multiplies" two signals. Here is my problem. I have an electrical unit with two separate circuits. One circuit drives the other one with a square signal. The ...
4
votes
2answers
92 views

Working satellite on 2 meters, at what arc distance to sun (center) will noise floor be problematic to a disruption of a communication path?

Is there some simple utility, or published set of charts, or suite of formulae, where one can approach the situation by inputting a space weather summary, (sunspots, various indexes, etc), the receive ...
0
votes
1answer
68 views

Solid angle for different E/H plane beamwidths

The solid angle formula calculates the surface area on a unit sphere, from projecting a rectangular patch onto the surface of a sphere. Image source This is calculated using the azimuth angle $\phi$ ...
1
vote
3answers
155 views

Do I always need a tuner at both ends of the transmission line or is that only for certain types of antennas/circumstances?

Last night was my first night on the air as a General licensee and at HF. I've got an IC-7300 with the built-in antenna tuner. I'm pretty sure I understand how to operate the radio, for the most part. ...
4
votes
1answer
61 views

no contacts with Rockmite

I finished building my Rockmite ][. It's running off of 3x 18650s, or 12v. I connected it to a MFJ-1840T and held the antenna horizontally in the air (also tried vertically) with my hand. I tried ...
1
vote
0answers
33 views

UK Intermediate training a not qualified newbie

I'm 99.9% certain that this will be OK, but independent verification would be reassuring. I am an "Intermediate" licence holder in the UK. This means that I am authorised to design and build my own ...
0
votes
1answer
44 views

Calculating receive wattage given transmit power, antennae dBi and path loss

I would like to understand how to calculate receive wattage given the following (excluding feeder loss and SWR): Transmit 50 dBm (100W) => 24 dBi directional antenna => 30 dB path loss => 24 dBi ...
0
votes
0answers
19 views

How do I alter the low power setting on a QYT KT-8900

There is no difference between the High and Low power settings. Both being around 25 watts. Is there an internal adjustment or do I have to re-program the radio?

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