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4 views

Limit of transmission in GSM 1800 band

What is the limit of a transmitter in the GSM1800 band (~1830 MHz)? The ETSI GSM specification states a limit of -47dBm between 1GHz and 12.75GHz (https://www.etsi.org/deliver/etsi_gts/05/0505/05.00....
0
votes
1answer
26 views

How can I design a microstrip patch rectenna that can power up 1W of payload?

I know the major components of rectenna should be Receiving antenna - Patch Antenna Matching circuit Low pass filter Rectifier - Schottky diode but I could not visualize how can we put all ...
3
votes
1answer
62 views

Turning raw APT data into an image

I apologize if this question is a little out of scope for the amateur radio stack exchange but I feel like it fit better here than over in any other forum. I have successfully parsed raw PCM data out ...
3
votes
2answers
87 views

What kind of loop antenna is this, and what is the relationship between its diameter and wavelength?

At the bottom of webpages in the advertisement swamps I keep seeing this image of an antenna, accompanied by an offer that I won't be clicking on. But the antenna itself looks quite intriguing. It's ...
0
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0answers
33 views

Silly doubt on Radio: A quest to find a radio station or online radio [closed]

I'm new here on this stackexchange so maybe this question will be offtopic. So I'm not searching a particular Radio Station. But, I'm searching a radio station with some "particularities". A all ...
0
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0answers
47 views

AM transmitter and reciver [closed]

How can I make circutes which can send and recive AM wave ? I want to send my Voice but i don't the circute which can transmitter and recive
3
votes
2answers
85 views

Actual Impedence of a folded dipole at resonance

I am using a Folded Dipole which I bought when I first got my General License. It was advertised as an all band antenna. My results with it were less than the claims made by the makers to say the ...
3
votes
1answer
81 views

RF Bridge Problem - K6BEZ Antenna Analyzer

(New, simplified edit of the original question) This question regards erroneous SWR measurements of K6BEZ antenna analyzer design from 2013 using Arduino and AD9850 DDS modules. There have been many ...
4
votes
1answer
264 views

How does a Viper Antenna work?

Are any of you guys familiar with a "Viper" antenna? It came up in a recent discussion with club members for higher frequency bands (6m, 4m, 2m). I hadn't heard of it before and internet searches ...
3
votes
1answer
83 views

Do Far-Field Radiation Patterns/Gains of NEC Software Accurately and Always Show the E-M Fields “Launched” by Vertical Monopoles?

Judging from posts on the Internet, this belief commonly is considered to be valid. But what is the correct answer?
0
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1answer
31 views

GNU radio companion raw captured data file split

My file is a simple raw data 32 bit floats sampled at 384 kHz. No metadata or anything alike. The file is some 10+ GB. I am looking for a method of isolating a certain group of signals from it into a ...
1
vote
1answer
33 views

voltage rating for RF filter components

I want to design a PCB for a diplexer for Satellite operations. I want to use SMD capacitors and possible inductors to get some experience with soldering SMD components. What should the voltage rating ...
2
votes
1answer
53 views

Convert NEC antenna file to .out-file for Wattwächter

I've just wrote a NEC Antenna file of my longwire with xnec2c on Ubuntu. To calculate protection distance with Wattwächter, I need an .out-file. Protection distance means the safety distance for human ...
2
votes
2answers
70 views

High Altitude Balloon Antenna Design

I'm designing a weather balloon with a club at college. We want to build the antenna from scratch to learn more about antennas but are at a loss as to which antenna design would actually work for high ...
3
votes
1answer
80 views

Trying to understand the work of 4:1 coax balun

Let's consider the following picture (source): When current passes the half-wavelength matching section it changes the phase to the opposite, this is why we get +V and -V in the feed point, 2V ...
0
votes
1answer
38 views

Had +5VDC and GND swapped, feeding a GPS receiver. Source is +5VDC output @ DB9 port on Yaesu FT-2600M, now showing 0V. Did I fry something?

Basically, I connected +5VDC to the ground of a GPS receiver, and now have no power from the power source. Is it possible to mess something up by doing this? I feel like this is more of a basic ...
4
votes
2answers
68 views

Does a dipole require a 1.5:1 balun?

Dipoles ideally have 72 ohms impedance. I know most of the time this isn't what one gets and it can vary a lot. But let's assume we can build this perfect dipole that exhibits this impedance. Why do ...
2
votes
1answer
66 views

300 ohm to 50 Balun at antenna feedpoint, or near receiver?

If I build a folded dipole, it will have an impedance close to 300 ohms. I have to match this impedance to the 50 ohms of my transceiver. I know many people match that impedance with varying lengths ...
0
votes
3answers
76 views

To folded dipole, or not to folded dipole?

I currently operate a 20M half-wave dipole with a balun. It's a little lower than ideal, but it gets me on the air. I've read about folded dipoles. But I've found contradicting information about them....
1
vote
5answers
129 views

Can I contact the International Space Station using my Baofeng UV5R?

I saw this article but I can't imagine the power output, (eight watts max) would be enough to be picked up by the ISS at 200 miles above me. Similarly, I don't know if the preamp on the receiver ...
1
vote
1answer
80 views

Use for Verizon 4G tower antenna

Our church had a Verizon Cellular site until about 6 months ago when Verizon cancelled the lease. After they left we negotiated for them to leave the cabling between the cell site and the antenna ...
1
vote
1answer
212 views

Any way to block one FM station

I live next to a 100 kW FM transmitter, 600 feet away transmitting on 103.7 MHz. It is south east and most other station I want to listen to are in other directions. This station comes though most ...
1
vote
1answer
44 views

Gnuradio AM broadcast receiver distorted audio

I have been trying to build a gnuradio AM broadcast receiver, but without success. I have tried a lot of combinations, but all of them produce a very distorted audio. I have an NBFM receiver using the ...
3
votes
0answers
43 views

Can the external VFO input in a Heathkit SB-(100, 101, 102) be used to operate on frequencies outside the radio's normal range?

I've got a Heathkit SB-102 that I'm working on making operational (problems with transmit, receiver works just fine). This model radio has a 9-pin Molex connector in the back, intended to connect an ...
2
votes
2answers
85 views

Does RF go through thin corrosion better than DC?

I might have a bit of a problem with my groundplane, but I am unsure. I am using a ground screen instead of radials. The problem is the ground screen is made of galvanized metal, but I can see that a ...
-4
votes
4answers
52 views

what is a good way to study for the tech test

I took the test last week but I failed it I was in a program that went through all the chapters but I just very bad at taking tests is there a way to go around the test
0
votes
2answers
65 views

ISOTRON 80m 75m Antenna Position

I know, a dipole is the way to go, but cannot fit one, only a 'birdhouse' antenna like the 75m 80m Isotron antenna. Is it better to put at 15 feet Above Ground Level outside, or 20 feet AGL ...
2
votes
1answer
55 views

Gain of Yagi turnstile?

I am currently working on a system to communicate with amateur CubeSats. I have decided to use the turnstile crossed-dipole style yagi because it is relatively easy to construct and uses circular ...
0
votes
2answers
80 views

Is roaming strictly a DMR feature or does it also relate to analog?

I've an AnyTone 878uv pluss and I want to know if roaming is only a DMR feature or if it can be used with analog repeaters?
0
votes
1answer
40 views

Audio too high, how to troubleshoot

I am using a TYT TH-9800 with a 10 m half dipole antenna on low power (5 W) to connect to a WIN linked repeater (+5.0 MHz offset and 123.0 tone). I made contact with two other stations and was told ...
0
votes
1answer
45 views

Can you measure how much radials you are lacking for HF vertical?

I have tried mount ham sticks on SUV and a convertible use trunk lid mount, especially on 40m on the convertible I notice the SWR changes from opening the door and close the door. Now I am quite ...
2
votes
3answers
87 views

Tweak antenna resonant frequency higher

This is a very simple question and I'm sure if I had a bit more background knowledge, I could figure it out myself. Let's say I have a 1/4 wave vertical antenna that is slightly too long, but it is ...
1
vote
1answer
41 views

How to calculate VFO/IFO frequencies?

I am trying to build a simple superhet receiver for listening SSB signals. I read several articles about SSB and got confused so I am looking for some practical explanation. I have 2 mixers, quartz ...
0
votes
1answer
59 views

Inverted L Feedpoint Height

I have this antenna EFHW 40-10 from Maple Leaf Studios. My current configuration: Inverted L with feed point 3m above ground, with "L" at 9m. I have 45 20-foot in-ground radials just below the feed ...
3
votes
1answer
83 views

Is it possible to receive weather satellites with a ham radio rig? (Icom 910)

I would be interested in receiving weather satellites (NOAA and Meteor) with my Icom 910. It has very good filters and could be a better solution than a simple SDR. However, its manual specifies that ...
2
votes
2answers
77 views

Using two VHF antennas vs one because of a large obstruction

We have a VHF Omni directional antenna, 2.5 W and 119 MHZ (approximate) mounted on top of a commercial hanger. Access to the antenna is out of the question because of the lack of fall protection. ...
0
votes
1answer
67 views

How can I manually programme these FRS channels onto my Baofeng UV5R?

I've been using Repeater Book to manually programme some repeaters in my area, up to fifteen miles. I later started programming some FRS, GMR, and MURS frequencies based on the CSV file that someone ...
0
votes
1answer
70 views

Can i use an anaolgue IC switch to change a 10 m yagi's directivity by somehow combining received signals with different variable phase?

Can i use an analogue IC switch being triggered at the same frequency I am receiving on to change a 10 m yagi's directivity by somehow combining received signals with different variable phase either ...
1
vote
1answer
76 views

SO-239 (UHF) vs N connector power handling on 160m

I am curious how much CW power an N connector or SO-239 connector will handle on such a low frequency like 160m band. I know on VHF they will probably handle about 800W before getting too warm. I ...
1
vote
4answers
85 views

Which 10 m antenna will give the most rejection in one direction for received signals which are vertically polarized?

I want to null out a particular direction so that i can't receive some vertically polarized interference on 10 m coming from that direction. Which 10 m antenna will give the most rejection in one ...
-1
votes
1answer
66 views

How would I calculate aperture efficiency for an antenna?

How to calculate aperture efficiency for an antenna with the following parameters: Big reflector diameter= 24 mm Gain= 9.265 dbi Frequency= 11.60 GHz
6
votes
2answers
88 views

Why aren't “ghosts” and intersymbol interference due to unmatched impedance (high SWR) a concern for HF receivers?

In amateur radio, we care about impedance matching when we need to keep the load within the equipment's specification (for best performance, or just to avoid damaging a transmitter), when we want to ...
0
votes
0answers
37 views

Text transfer From/To SDR

I bought a hackrf one and I don't think it works. Before I return it can someone show me a grc flowchart on how to send text or a text file from a hackrf to a rtlsdr? I have been told you can do it. ...
4
votes
3answers
1k views

Vertical Yagi spun at 1000 RPM: gain properties?

If I were to mount my 10 m vertical Yagi on a pole with a motor attached at the bottom with the appropriate fastening and coax mounted via electrical brushes, if the Yagi is spun at say 1000 RPM would ...
1
vote
1answer
25 views

CHIRP-programmability of the Alinco DR-635T/E

I am a beginner in ham radio and am trying to program repeater data into my Alinco DR-635T/E VHF/UHF mobile radio. The manual that came with the radio is so poorly written that I could not ...
1
vote
2answers
55 views

Batch sampling SDR

I am using RTLSDR on macOS with Cubic SDR, it works great and is very intuitive. Now I want to do a frequency envelope analysis where I need to basically 3-d plot intensity versus frequency and time. ...
3
votes
1answer
75 views

Does copper wire get sold as flat straps to reduce inductance?

The extra book (11-9) safety section mentions that a "large diameter wire, or even better, a wide flat strap, has the lowest inductance and makes the best ground connection." Does anyone actually have ...
4
votes
1answer
192 views

Will painting a 4 element 10 m yagi using conductive paint onto the side of a building work?

Will painting a 4 element yagi using conductive paint onto the side of a building work?
1
vote
0answers
34 views

Why is self-resonance important in a loop antenna?

I visited a "small loop antenna" calculator web site today and fed in my horizontal loop gepmetry, curious to see what it would say. 2" dia wire, 72' circumference, 3.935MHz. Interesting results, ...
1
vote
1answer
42 views

Is there a suitable alternative to using a metal pole to mount a vertical yagi apart from wood and fiber glass?

Does anyone know if a non-metallic pole approx. 4 m long is available that i can use to mount a vertical 10 m 4 element yagi ? that is not wood, PVC or fiber glass as these are either too heavy or not ...

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