Questions tagged [receiver]

Use this tag for questions about the theory and structure of receivers.

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18 views

Setting the maximum Tx Power value for the USRP transmitter

In order to simulate the measurements on the computer (in the WinProp environment) I have to set the maximum Tx power: To find out what the transmitter signal power is, I checked it on the spectrum ...
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3answers
74 views

what is the baseband for CATV?

I was reading on wikipedia this: the subscriber's television or a set-top box provided by the cable company translates the desired channel back to its original frequency (baseband) But when I ...
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2answers
109 views

Why am I receiving a local tv channel on a CMB frequency

I am using a simple Baofeng H6 dual band radio and I programmed weather channels. Well, on frequency 161.77500 I am actually picking up WGN, a local tv network. This frequency should be reserved to ...
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96 views

What causes an AF amplifier to make popping sounds in a superheterodyne receiver?

Recently I've made a simple single IF superheterodyne SSB receiver for 40 meter band. The schematic is available here [PDF]. VFO and BFO are based on Si5351, the AF amplifier is LM386. It works OK but ...
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1answer
63 views

Modeling a regenerative receiver

What is the signal processing model of a simple regenerative or super-regenerative receiver? Is it just a linear 2-pole IIR filter with gain? How does a single regen control knob control both ...
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136 views

WWV interference all over the band!

I have a mid-era Hammarlund HQ-129-x. It sounds great if I don't count the motorboating. But the problem is in the middle bands. I got the radio way out of alignment, and managed (I think) to get ...
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3answers
321 views

SDR: How are I and Q determined from the incoming signal in quadrature sampling on the receiver side?

I'm new to digital radios and signal processing, so I apologize if this question is trivial but I haven't been able to find an answer here or by googling. Also, some terminology might be off, please ...
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105 views

Receiving multiple signal

Maybe this is a really silly question even from me, a completely amateur... But I like to know about how's the antenna output when its receive multiple signal Is it possible different signals on ...
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2answers
117 views

Benefits of AGC?

I note that many popular kit and QRP radios do not include any AGC capability. Thus it must be possible to operate successfully without AGC. Are there difficulties involved in manual gain control? ...
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2answers
42 views

Detecting receiver intermodulation distortion?

On some (most?) receivers, if the RF gain is turned up too high, intermodulation distortion increases due to increasing non-linearities (maybe even clipping, etc.) Is it possible, just by examining ...
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1answer
58 views

Tradeoffs: varicap vs. air variable capacitor for Rx bandpass?

What might be the tradeoffs between choosing varicap diodes versus air variable capacitors in the design and construction of tunable bandpass filters for HF receivers?
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1answer
112 views

Receiving an Coded Odd Signal at 137.25MHz but don't know what it might be. It can affect my detection on NOAA 19. Need help

I am a newbie trying to detect NOAA 15, 18, and 19 satellites, which have downlink frequencies between 137 MHz and 138 MHz. I am using an SDR dongle and attached a photo of it to this post. Of course,...
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3k views

Why does the audio on my FM transceiver cut out every 5.5 seconds?

Specifically, my Icom ID-4100a. What's interesting, is that this happens in MR and VFO modes... but NOT when using the built-in WX stations. For example listening to WX-01 (162.550 MHz), no problem. ...
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2answers
269 views

Does the output of a BFO for a short wave receiver have to be exactly a sine wave?

I want to build an external beat frequency oscillator (BFO) for an old valve Eddystone receiver I have. There are many circuits for BFOs on the internet, they are mostly similar, the idea seems simple ...
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2answers
670 views

How to calculate power transmitted by monopoles?

I only studied monopole in sending mode or receiving mode alone but never in both modes together, I have this question which says: Two vertical λ/4 monopoles are parallel to each other with 20 ...
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56 views

Buzzing FM interference

What kind of interference or other receiver issues can cause a constant buzzing noise (picket fence lines in the audio spectrum) in the demodulated audio of a received NFM VHF signal? With AM, it ...
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1answer
37 views

Combining two CFU455IT +/-2kHz (4kHz) ceramic filters to get a +/-1.25kHz (2.5kHz) filter for SSB

Can I put two of these cheap (less than 3USD) and common CFU455IT +/-2kHz (4kHz bandwith -6dB ) ceramic filters in series to get a lower bandwidth good for SSB TX? If I'm correct I will get -12dB at +/...
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1answer
70 views

Baofang uv-5rA/ repeater trouble

I programmed my Baofang UV-5RA radio to my local repeater about less than a 1/4 mile away. When I cue the mic and release, I get a signal from the repeater. However, I can only hear people if I have ...
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1answer
59 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 ...
6
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1answer
152 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 ...
4
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1answer
123 views

Commercial Loopstick Antenna Manufacturers?

I am an electrical engineer working on a product that needs a loopstick antenna. I had thought that AM radios were so commoditized that I'd be able to find an off-the-shelf vendor. However the closest ...
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2answers
155 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 ...
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3answers
592 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 ...
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1answer
74 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 ...
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109 views

Unknown kit from DK0TV

When my father - who became a ham years after I did - passed away, I found an unstarted project (board + components), which I only re-discovered again years later. The board is marked DK0TV-001, and ...
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102 views

Is there any 2.4 GHz tuner ICs for SDR receivers?

I have a hackrf one sdr, which i use to transmit test signals. I am using ISM bands, so I can omit transmitting my callsign, checking correct sub band (FM, digital) etc. And one of most interesting ...
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319 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 ...
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2answers
159 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 ...
2
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1answer
82 views

How much field strength to blow out a receiver?

I was wondering what calculations would need to be performed to find out if a receiver will blow out in the given conditions. Portable AM receiver with ferrite rod antenna 200 ft away from MW antenna ...
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2answers
83 views

How is frequency selection (tuning) accomplished in a direct conversion receiver?

How is frequency selection (tuning) accomplished in a direct conversion receiver ? A crystal filter can't be used is that correct ? Because there is no IF to mix with the incoming frequency band ...
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1answer
97 views

Locate a ball 1000 times a second

I want to locate a small ball in the air 1000 times a second. The ball is thrown from the ground and then flies in the air for 0.5 seconds until it lands. Distance from the location instrument is 1 ...
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3answers
223 views

Will a “crystal set” work with an untuned RF amp stage?

In my ongoing process of building up to a homebrewed general coverage receiver/transceiver, a first step might reasonably be a crystal set, where a tuned circuit and simple, or even improvised, ...
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39 views

Problem to paralel tv digital reciever [closed]

Here is my C-Band parabolic tv digital receiver. As shown by the pictures, the incoming coax cable (INPUT) connected both the outer and the core. One goes to digital receiver 1 (receiver 1), and ...
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91 views

Has this regeneration control been done?

I'm planning to build a two-tube reflexed RF regen receiver soon. I'm examining methods of controlling the regeneration — it needs to be possible to both initiate and halt oscillation in all bands (I ...
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1answer
63 views

Unusual modulation

I've been writing a SciFi story, and it calls for something very unusual to happen. I'd like to check this idea for plausibility, but as I'm not a radio ham myself, I don't know if this already exists ...
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3answers
179 views

How to make simple AM detector using an LED?

I'm new to amateur radio, and as a beginner project, I wanted to use some of the basic components I have to create an AM receiver. Anyway, what I'm trying to do is create a simple AM receiver that ...
2
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1answer
393 views

Frequency Display for Old Tube Radio

I have a Hallicrafters S-120 1960s vintage vacuum tube receiver (an "All American Five" superhet with solid state rectifier replacing one of the "five" tubes). It works well, doesn't have excessive ...
2
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1answer
100 views

Radio antenna for my FM receiver / Android FM

I want to make a radio antenna at home which will be able to receive all FM frequencies for my FM radio or Android FM. How do I make it? Frequency it can catch : 88 - 108 MHz Thanks.
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499 views

How do I listen to the amateur radio satellites?

I'm new to amateur radio, and I would like to listen to those satellites in the orbit. Where do I start? What types of amateur radio satellites exist?
3
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2answers
207 views

Determining whether signal meets the 12 dB SINAD voltage

The specification for a certain radio receiver says: Typically 12dB SINAD NBFM for 0.15uV at 145MHz. If I understand correctly, this means that the received radio wave should have a voltage level of ...
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1answer
44 views

Passive receiver power needs & data rate

I'm working on a project to design a space-based low frequency array. It will only be receiving signals, and it will operate between 10MHz - 100MHz. It is made of short wave crossed dipole antennas. I ...
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2answers
79 views

Why do receiver sensitivities vary so much with frequency?

I was looking for a 2.4 GHz WiFi antenna to catch a weak free WiFi signal, and amplify it so I can use it. I found Ruckus Metroflex NG, which can receive signals down to -108 dBm. Which is amazingly ...
6
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1answer
149 views

Why does adding 50-ohm BNC Ethernet terminator(s) in parallel to my 4-element yagi improve my radio's reception? (70cm)

I have this radio, with a rubber duck antenna, and a repeater twenty miles away to my north-northwest. If I set my radio on the top of a cabinet in my bathroom, I receive the repeater fine. I can't ...
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3answers
1k views

Substitute for 455 kHz Ceramic filters in new designs

I am looking to design a dual conversion FM receiver/power meter for t-hunting similar to the MK4 sniffer using 10.5 MHz and 455 kHz IF. In my research it appears that manufactures have stopped ...
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2answers
184 views

What equipment and software do I need to read raw civilian GPS signals on my Mac?

This is a hobby project to learn more about GPS technology.
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2answers
1k views

Can a FM tuner (receiver) be detected and triangulated?

In movie "6 Below", based on a true history, a lost snowboarder at Mammoth Mountain (California) is located by search and recuse when they detect and triangulate a signal from his MP3 player that also ...
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72 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, ...
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1answer
2k views

Why would you need a signal generator to receive early satellite transmissions?

I recently watched, on You Tube, a NOVA program about the British school masters and students who were the first to publish the news that the Soviets had started launching satellites from a new launch ...
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2answers
219 views

How to identify a practical HF communication receiver?

I've recently purchased a Hallicrafters S-120 -- 4-tube superhet receiver from the 1960s, continuous tuning from 540 kHz to 30 MHz, bandspread control, and a regenerative IF that doubles as a BFO for ...
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1answer
144 views

ICOM IC-910h How much bandwidth does it listen when receiving USB and FM?

CD-audio has a bandwidth of 22kHz. CW usually has a bandwidth between 3 to 5 kHz. But I am wondering what is the bandwidth my Icom IC-910H can listen to in both, the SSB and the FM mode? Also, what ...