# All Questions

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60 views

### What should I take into consideration when choosing a new antenna? [closed]

I am trying to choose a new antenna for the HackRf One, but there are several variables to consider, such as the frequency, threading, resistance etc. In general, what things should I take into ...
131 views

### Mismatched Radios: A Baofeng UV-5R & a Cobra ACXT 645 [closed]

I've got a Baofeng UV-5R and a Cobra ACXT 645, and I'm trying to get them to communicate. The Cobra transmits and the Baofeng (programmed with CHIRP) receives, but not the other way around. I've ...
55 views

### advice needed for balanced line terminals

I am designing a portable antenna with a radiating element and a balun that are not close to each other. The impedance has been designed to be close to 50 ohms. ...
58 views

### Can my neighbors ham radio station be preventing my TV antenna from proper reception? [duplicate]

I have a winegard 8200 series antenna and it worked flawlessly in getting me reception of more than 70 stations. The wind blew it down and I couldn't replace it for about 6 months due to the fact that ...
129 views

### Simple Gnuradio TX/RX loopback example/tutorial

I'm looking for some sort of simple and a beginner level instructions on how to build TX/RX loopback flowgraph using GnuRadio software and B200 USRP with an attenuator FW -10 + 10dB. Kindly, help me ...
33 views

### Unsure how to assemble Shakespeare SSB antenna; not working [closed]

Have 23 foot Shakespeare SSB antenna. Can not connect through the side feed termination band? Antenna not working? What is the band supposed to look like? Is the termination band supposed to be ...
72 views

### FLDigi Crashes When Trying to Load RigCAT Description File

I am trying to setup FLDigi with my ICOM-7300 via the USB connection so I can start using digital modes. Everytime I try to follow the instructions here, it doesn't work. Specifically, everytime I try ...
48 views

### Baofeng 888s side key didn't work and solved [closed]

Thanks. Solved. Baofeng 888s, programmed with chirp, worked great. I hit the device with CHIRP many times, Everything was ok., but moni button after a month, didn't work. First I thought that the ...
43 views

### Baofeng 888s sidekey (moni) don't work

Baofeng 888s, programed with chirp, worked good but maybe at change channels during pushing moni button or something else (I don't know), don't work. I tried to change side key options by programming, ...
99 views

What is the definition of these terms? Would a system with signal to noise ratios of uplink 100dBHz and downlink 80dBHz be downlink-limited?
62 views

### Building a ray tracing path-loss propagation model of LTE for small cells (pRRus) [closed]

Phones will receive signal from many pRRus. Should I average the antenna gain and all the path-loss (both line of sight and no-line of sight)? Or should I sum them all together?
60 views

### Are jammers relate to electronics or electrotechnics , why? [closed]

Are jammers relate to electronics or electrotechnics , why ? Please ,tell me the main difference between electronics and electrotechins and why we can classify jammers as electrotechics or ...
55 views

### Looking for a formula used by VE6YP trap calculator

I wonder whether the source code of VE6YP (Tony Field) coaxtrap design program (link 1, link 2) was ever published or described. As a Mac user I'm having little difficulties using this software and I ...
67 views

### Parasitic inductance of relay contacts

I need to switch a bank of filters operating on bands from about 2MHz to 30MHz. The parasitic series inductance of the relay contact system will have an effect on the performance of my system. ...
86 views

### Retuning 2m Duplexers (Q2330E) with Spectrum Analyzer and Tracking Generator

Yesterday I was trying to tune up the duplexers one can at a time as listed in this Sinclair Youtube Video. After tuning them my receive is awful and my transmit is somewhat not what it used to be. ...
58 views

### How to limit frame transfer in Gnu Radio Companion?

I have as source a bit frame, then I modulate it, to finally transmit it with my HackRF. I can receive and decode it normally with another HackRF. However I would like to limit to a number of frame ...
67 views

### Using SW radio to detect Jupiter

I read here (in the ideas section) that an old shortwave radio can be used as a receiver for listening to Jupiter but am unsure about how to do it. MY radio has both a whip and ferrite antenna, ...
95 views

### 2GFSK 9600bps Transmitter and amplifier for 433 MHz

I'm looking for a reliable, however cheap solution for ground-space communication. I need at least 50W of transmitted power with 2GFSK modulation at 70cm band (433 MHz). Transmission will be done ...
41 views

### Any reception reports from ExseedSAT1 yet?

My answer to the question Where can I find the TLE of ExseedSat 1, India's first ever private LEO satellite? is currently that while 60+ objects are being tracked from this mutli-payload launch, ...
78 views

### unexpected output using HackRF One with rx_power

I am trying to make a wide scan from 24M to 1700M using HackRF One by using: rx_power -f 24M:1700M:1000k -g 50 data.csv This gives me a nice output like this. ...
28 views

### To decide coherent time and fade duration from measured received signal spectrum and relate them to channel modeling

This question was asked in Electrical Engineering 2 days ago but hasn't received very informative responses. https://electronics.stackexchange.com/questions/387255/decide-coherent-time-and-fade-...
125 views

### AWR_4000 by awc programming software [closed]

Ware can I find the programming software for this radio It's cold awr advantage programming software for the 4000 4002 anyone know or has a copy of it to send on email to Mr ouly of you can email me ...
71 views

126 views

### TM-V71A Echolink - Constantly Transmitting

I just got a Kenwood TM-V71A, and I really want to use it for Echolink operation as a simplex node. I got it mostly working, but there's one huge problem - it's constantly transmitting over the ...
75 views

### Can a radio antenna damage a phone? [closed]

I am currently attending a radio technology course. We continuously work on radio sets that are sometimes used as manpacks by the Army. In order to learn how to operate them we work in close proximity ...
256 views

### What are the key differences between Hytera DMR and MotoTRBO?

What I'm really curious about is if anyone can provide a high level overview of the two technologies. I know that they are both utilizing the DMR standard, but from what I have read is that the way ...
89 views

### “;” in morse “-.-.-” or “-.-.-.”? [duplicate]

What is the correct sign for ";" in morse? FLdigi converts "-.-.-." to ";" whereas in various code lookup tables I see "-.-.-" Can both be used or is one of the morse codes valid?
935 views

### How do I install the DV4mini software on Ubuntu?

The documentation says the following: The program requires the complete installation of Mono. You install for example with apt-get the packet mono-complete. Until an installation packet is ...
222 views

### Is there any open-source solution to scanning / decoding GSM/UMTS traffic? [closed]

I want to build a passive (rx-only) scanner to listen to GSM and UMTS traffic. I am not interested in breaking encryption or anything like that - but more interested in collecting statistics and such. ...
334 views

### GNU Radio code and data type conversion

I am a GNU Radio beginner, and I use the following code to make the block's output-port output a pmt data: ...
372 views

### FSK Rx sensitivity with different deviations

I used an RF generator transmitting FSK packets with a datarate of 50 kbps. The deviation was 12.5 kHz. With this combination of datarate and deviation the modulation index is 0.5. I found that my ...
38 views

### Determining if what's on a frequency is signal, or noise [duplicate]

I have the spectrum binned into 5kHz bins. For each bin, I'd like to determine (via software) whether what's in that bin is primarily signal (an FM broadcast station; a ham repeater) or noise (just ...
160 views

### Yaesu FT-65R quick function keys: changing values

I am using a FT-65R radio and loving it much. However I have a problem with assigning menu items to P1-P4 buttons. If I assign CTCSS menu item to, let's say P2, then after pressing P2 the menu item is ...
145 views

### Information on GSM [closed]

My team and I are using a SDR, GNU Radio, and some other hardware assembled into a custom tablet and a Python program we are writing to detect IMSI Catchers. I have some Packet Capture files with ...
556 views

### Autoranging problem for AX5043 transceiver (437.025MHz)

I am trying to configure AX5043 transceiver(ONSEMI) for PSK modulation and system parameters are as follows: ...
99 views

### Antenna Impedance calculation for low frequency [duplicate]

If I have an end fed long wire in free space, say 100 ft, how do I calculate its $R$ & $X$ at different frequencies?
58 views

### How to connect a motorola RVA50UL with MR350?

Currently I use a Motorola MR30R radio in the frequency 20 (462,6750 Mhz) with Interference Eliminator Code 59. I also have a Motorola RVA50UL, according to the manual, the frequency will be available ...
75 views

### Able to consistently pass the US B license test; what more is needed for a Danish amateur radio license?

I need to cram the last bits for my exam - I don't know my competence level precisely, but I've passed the US B-license tests a bunch of times. Problem is I'm in Denmark - how should I cram for this ...
90 views

I got my license 25 years ago. I bought a 2-meter ham radio from Radio Shack (\$200). I am thinking about renew my license and re-start this hobby. To my surprise, local Radio Shacks no longer carry ...
46 views

### Can two directional antennas be connected without an amplifier to improve reception? [duplicate]

Can two identical yagi antennas be linked together to improve a cell phone signal? The idea is to put one antenna on the rooftop and the other in the house, and connect the two with feedline but no ...
78 views

### Practical Resources for the Amateur Radio Student? [closed]

What electrical circuits can be easily build by someone with basic electrical engineering skills that exemplify the fundamental components of radios, antennas and so on?
45 views

### Relay cross reference for 1925-3-2

My amateur radio uses 1925-3-2 relays on the low pass filter board to select bands. This relay is no longer available. Is there an alternative I can use? Or something?
67 views

### Is it suitable to use DSSS in a narrow-band channel for a power-starved system

I want to build a system that can transmit data through 2-way radios as far as possible. I use the "line-in" as the input of the baseband signal in the transmitter and use the "audio out" as the ...
87 views

### OCF Antenna Feed Line [closed]

I built a OCF HF antenna. The feed line contains a 4:1 balun and a line insolator (choke) per instructions. When checking the radio end of the coax, I get a "grounded" response between the inner wire ...
70 views

### Receiving BFSK with 9.6 khz deviation on TS-2000 / ICOM(IC-910H) in FM mode

I have used Kenwood TS-2000 to receive BFSK signals with 3.3 khz deviation operating the TS-2000 in FM mode. Can we receive similar signals but whose BFSK deviation is 9.6 Khz using either the TS-2000 ...
85 views

### Australian Police Radio Frequency [closed]

Does any one know or have a frequency chart with Australian Emergency services?
286 views

### Activities for High School ham radio club [closed]

I just started an Amateur Radio Club at our High School (KE0FXH) Our school is not a technical school (it is an arts school) and I am trying to find activities to get students interested in ham radio ...
54 views

### Transformer secondary coil impedance [closed]

To transfer maximum power from the secondary coil to the load, I need to find secondary coil impedance. My load impedance 5 - J365. I would design a matching circuit between load and secondary coil, ...
249 views

### What will be antenna impedance of a dipole antenna when it is kept lambda/2 away from the transmitter

I understand that half-wave dipole antenna, which is in far-field, impedance is around 73 ohms. If I keep same antenna in near-fied at distnace lambda/2 from the 1.25 lambda length tranmiter?
117 views

### Amateur licenced operation and wifi

Is it wise to use my call sign as SSID on 802.11x spectrum. I wish to be known. My question more pointently is, is it common for amateurs to ID on shared common wifi frequencies.

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