# All Questions

2,970 questions
Filter by
Sorted by
Tagged with
320 views

### What is the directivity of thin dipole antenna of length 1.25λ?

I want to know about the directivity of thin dipole antenna of length 1.25λ for my assignment.Is there any formula related to its length?
116 views

### How to compute/simulate signal propagation latency?

I need to transmit small amounts of data (~5kb/s) in the fastest way possible over the distance around 2500 km. What is the the best way to carry out such transmission? How could I estimate or ...
3k views

### Motorola Maxtrac Programming with windows 7 and DOSBox

I found an old Motorola Maxtrac in a parts truck I bought. I'd like to program some channels into it with a Windows 7 computer and DOSbox. My first issue, is I'm having trouble identifying the radio ...
73 views

### Magnetic antenna for the UV8000E

I have the new UV8000E ht and I'm trying to find a magnetic antenna or at least the adapter that allows the unit to be attached to a pl259 connector. I have no clue what the connector is other than ...
262 views

### Why is this signal recognized as PACTOR II but not decoded?

I'm using SDR# and with virtual audio cable sound is piped to Wavecom W-CODE. W-code recognizes a frequency on 4 and 24 MHz as Pactor-II with 100% confidence, but he can't decode in terminal text ...
217 views

### Using RF6886 Power Amplifier for VHF design

I want to use RF 6886 power amplifier for VHF band design. The datasheet doesn't mention VHF design specifications. Has anyone used the PA for VHF design? If yes then please share your designs.
259 views

### RCA victor 35x tube radio loop antenna replica?

There is this one youtube video I have not been able to find again, where someone with a similar model radio was making replica of the original loop antenna on the back. I am wanting to make a ...
82 views

### What parameters are currently possible in a directional antenna less than 5mm long?

I'm curious what kind of directional antennas could fit inside a cell phone, which would require it to be 5mm or less in its longest dimension. I know that the length of a directional antenna is often ...
169 views

### Military Amateur Radio Service (MARS)

The Navy MARS program was officially decommissioned effective 30 September 2015. What is the state of the other MARS programs (Army and Air Force)? Is it known that they too will be decommissioned in ...
232 views

### Kenwood TS-440SAT & TS-930SAT Refurbishing

Inside my TS-440 & TS-930 are (former) foam pieces. They have disintigrated into a pile of dust in the bottoms of the rigs. I am more than sure that Kenwood does not have fresh stock off these. ...
178 views

### CC1125 reference design matching network using Smith chart

I am trying to confirm on a Smith chart the matching network for 169MHz frequency using an external PA and and 437Mhz with an external LNA. I am not able to end at the origin of the Smith chart using ...
139 views

### Is there a satellite tracking software with S-band downlink

we are trying to track "DTUsat-2" which transmit at 2.402 GHz using automatic frequency adjustment to compensate for Doppler shift. Our receiver ( a professional one) have the ability to set frequency ...
176 views

### CW paddle interface wiring problem

I have the MFJ-564B iambic paddle which I need to wire to the MFJ-552 CW interface. The paddle is stereo (dits/dahs) and the interface is mono (when connected to paddle, only gives DITS). How can I ...
192 views

### How can I reduce power consumption and thermal dissipation in power amp?

I am designing a Class-E power amplifier in UHF band using ADS. Now I have 20dBm fundamental output power with 13% PAE, which is low for this class of PA. The problem is that I have thermal ...
73 views

### What is the required signal-to-noise ratio for a AX5042 transceiver?

What is the required signal-to-noise ratio of a AX5042 transceiver IC?
1k views

### Baofeng not finding CTCSS tone

I have this Baofeng and I want listen to my school radios. The problem is that I want to find the CTCSS tone for the fun of it, but when I scan the tones on the Baofeng it cycles through but does not ...
219 views

### Testing my HB-1B QRP CW Transceiver on 40m

I'm a new ham and have only used 2m/70cm so far. I have recently completed a QRP CW setup: a YouKits HB-1B transceiver and a simple wire dipole. I haven't made any contacts yet, and I'm wodering if ...
665 views

### 2-Pin Kenwood to Sound Card (Beofeng UV-82HP & ASUS Xonar Essence STX)

I have a Baofeng UV-82HP that I want to use to TX and RX to a TeamSpeak Server. For this I'm going to use a dedicated computer, for both the client and server that has a sound card (ASUS Xonar Essence ...
1k views

### Chip with price and functionality to the RDA1846?

Is it possible to buy a cheap transceiver chip with similar functionality to the RDA1846? I'm looking for something else, because I'm wary of buying a probably counterfeit chip on AliExpress, and I ...
326 views

### What are the signal loss mechanisms between a ground station antenna and a satellite receiver?

What are ALL the potential signal loss mechanisms between the output of the earth station antenna and the input of the satellite receiver. With a bit of explanation for each if possible please.
171 views

### How does a multi-element vertical work?

For example, Diamond makes the X700HNA which is stated as a 4x5/8 vertical on 2m. Does this just mean that it is 20/8 wavelength long vertical? Or is there some magic to phasing the 5/8 segments? I'...
89 views

### What does the current signal look like just south of Las Vegas? [closed]

I was wondering if it would be worth it to engage some of the hotels south of the strip to see if they would allow us to put a repeater on one of the buildings there. Just wondering as the Marriott, ...
6k views

### Vertical Antennas: Compare Cushcraft R9, no radials to 43 foot vertical with ground radials

Small lot, must go vertical. Which antenna will preform better, with less noise, good DX. Cushcraft R9, NO ground radials. Or, 43' with ground radials.
94 views

### Can wood be used to build 6m quad? [closed]

Could I use wood to build 6m quad? If not, what material(s) would be better/more useful?
6 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 ...
32 views

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

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 ...
44 views

### AM transmitter and reciver [on hold]

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
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. ...
24 views

### UHF cubical quad VNA analysis interpretation (part2)

This is the follow up to: UHF cubical quad VNA analysis interpretation This is a S21 and S31 analysis of an oversized 385 Mhz 50 Ohm to 90 Ohm balun between 100 Mhz and 600 Mhz I tested phase ...
25 views

### Is there and data anywhere showing if amateur radio operators are more likely to get cancer from exposure to RF?

Is there and data anywhere showing if amateur radio operators are more likely to get cancer from exposure to RF ?
120 views

### Why are no 2w FRS walkie talkies on the market?

I have read that the new laws regarding FRS radios state that you may use up to 2 watts power, yet I can't find a single 2 way radio that advertises 2 watts power; only .5 watt, or they don't state ...
37 views

### Gnuradio loopback flowgraph is not working

I found the below uhd_two_tone_loopback example (which is one of the gnuradio provided examples) and I am trying to run it, it runs but I can't receive signal. EDIT: I mean when I run the program I ...
23 views

### Can a butler matrix have variable phase shifters instead of fixed ones?

If not, why are fixed phase shifts required?
31 views

### What the difference preamble and access code?

gnuradio packetize using access code for start sync packet, but another example attach the preamblee, so what the differences preamble and access code ?
42 views

### A gnuradio program that can output some arbitrary waveform read from a file containing I/Q values

I am trying to figure out how to create a gnuradio program that can output some arbitrary waveform read from a file containing I/Q values. I would highly appreciate any guidance in this topic. Simple ...
54 views

### Can I make a simple Tx/Rx antenna (Radio System) which will receive signal from BTS and broadcast/transmit it, and vice versa? [duplicate]

Consider a situation as below. I am stay in a farm field, which my house is 9.4km distance from the nearest and the only one BTS (Base Transceiver System), a cellular antenna for transmit and receive ...
70 views

### No module named 'analog_swig' [duplicate]

I know guys you gonna tell me tat there is something wrong about GnuRadio or Pybombs installation. Well, this is my third time during the past 48 hours I reformat the OS of my mini pc fitlet2 mint ...
44 views

### No module named _osmosdr_swig [duplicate]

I am trying to run GnuRadio python code in my python web server and got the "No module named _osmosdr_swig" error. Please, what is the cause for this error? I know it sounds like so obvious that I ...
49 views

### Qt application freezes after a fixed time period

I have an Ettus E310 from which I send some data via ZMQ to a computer. On the remote computer I am running a Qt GUI in which I am displaying a FFT and a variable. After about an hour, the GUI needs a ...
76 views

### Troubleshooting ICOM PS15 Power Supply

I got a power-supply gifted by my friend. When I powered ON, the main (120V) FUSE blows up. I started by disconnecting the transformer from the control circuit and powered ON. This time the fuse is ...
103 views

### How can a vertical Yagi for 10 m be mounted on on a vertical metal mast and be made to work properly?

From a reply to a previous post I've been told that a horizontal tube half a wavelength long mounted right at the junction between the boom on a vertically mounted yagi and a vertical metal pole will ...
884 views

### Input and output impedance of antenna/circuit: theory and measurement methods?

As illustrated in my previous post, I got stuck with the matching circuit between an receiving antenna and my circuit, including a rectifier and sensory circuits. I got confused with input and output ...
632 views

### Yaesu FT-450D How to troubleshoot problems with the Keyer jack

I am a big fan of the Yaesu FT-450D but there is one really frustrating quirk that took some time to figure out. The FT-450 has a keyer jack on the front panel. It is the lower of two 1/8 inch ...
233 views

### Yaesu FT-8800 + TinyTrak4

I´m using the Yaesu FT-8800 with the Byonics TinyTrak4 as APRS tracker in my car. There is a menu setting to bind the data jack to a VFO, but transmission is always done using main VFO. So if I talk ...
111 views

### Separated audio and ptt

how important and why is the audio, ptt ev. CAT interface separation from PC? I saw solutions with separating transformers and PTT, but directly connected CAT. Does it make sense? And is there any ...
128 views

### Using 'amodem' to transfer digitally using a UV5R

I reviewed docs for amodem, and it looks like I can send files and possibly other things with this. I should only need to prep my computer as per the doc and set VOX correctly. Does anyone have ...
139 views

### Feed line direction for Quad antenna

I am currently getting my EE degree, and I'm trying to build my first antenna for a weather balloon. I understand with a dipole, you want the feed line perpendicular to the antenna for at least l/4, ...
76 views

### Transmit data without line of sight - Legal, fast, cheap and error corrected

I go camping to France every year. There is a wifi station at 200 metres from where I camp, but I don't have a direct line of sight (it's on a slope). I can put a shoebox at the base station, but I ...
A radio receiver needs $1 \textrm{ nW}/\textrm{m}^2$ of power density function, how far away from a 1-watt point source will it continue to work?