Questions tagged [receiver]

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

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RF Coax Termination Question

I am looking to terminate a line with the below characteristics and having a hard time locating an RF coax terminator. Can anyone help? I have an FPGA HW that is feeding multiple receivers. The input ...
Newb's user avatar
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8 votes
3 answers
2k views

Can larger antennas damage an HT radio?

Can adapting a larger antenna such as a Diamond X-50 or larger mag mount damage an HT radio? Would it overload the receiver?
Radio Rails's user avatar
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0 answers
48 views

ICOM R8500-Transfer data and audio through e-line services

I have tree icom R8500 radio receivers and i want to upgrade my services from serial to Ethernet. Although i have successfully managed to transfer data from the receivers to my pc (which happens to be ...
2 votes
3 answers
233 views

How do radio jammers work?

I just want to prefix by saying I asked where to post this question on meta and no one was 100% sure but this seemed to be the most likely fit so please tell me if this is off topic and where I should ...
Ethan's user avatar
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1 vote
1 answer
371 views

Need some help to design a DIY MW Radio receiver

AM Medium Wave Radio Receiver Design. First of all, I am a hobbyist and stuff related to electronics are not very strange to me but the chapter of Radio and RF frequency , intermediate frequencies , ...
CoderBittu's user avatar
3 votes
4 answers
491 views

Using UV5R HTs. Will i lose receiving range by attaching coaxial cable to put my antenna remotely as well as higher?

Using beofeng UV5R HTs. Changed antennas to retevis whips. Will adding coaxial cable to HT & antenna for height reduce or increase reception. As i'm in a valley. I receive only. As i'm still ...
Snowy's user avatar
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4 votes
1 answer
537 views

60kHz WWVB receiver help

I have built a large ferrite loopstick antenna based off this video. I live in Washington state and am trying to receive and decode WWVB. I can get my antenna to resonate at 60kHz with ~700 pF of ...
Max686's user avatar
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1 vote
2 answers
268 views

Questions about a Realistic Pro-25 Scanning Receiver

Almost complete noob here. I understand basic concepts of radio, frequency, the reason for clock crystals, etc, but not how it all works together in a circuit. I love to play with gadgets and that is ...
jewettg's user avatar
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3 votes
3 answers
151 views

Serial Inductors in Tuned Circuit - Elenco AM780K AM Radio Kit

I'm trying to understand a component of an AM radio kit that I have. (There is a document available here: https://www.elenco.com/wp-content/uploads/2017/10/AM-780K_REV-K-2.pdf describing the build ...
Jared's user avatar
  • 201
5 votes
2 answers
164 views

How can AM radio work differently when approaching the true frequency from different directions?

I bought a very cheap world band receiver, Nedis RDWR1000GY. It has MW, SW and FM reception. MW is useless where I live (no MW stations nearby and signals don't propagate far), but I was primarily ...
juhist's user avatar
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1 answer
386 views

Why is the Air Band distorted at times with SDR Sharp?

I am using SDRsharp to monitor air band with an RTL-SDR dongle. Sometimes I receive ATC voice clearly but at times it's distorted, I am using RTL AGC gain of 29dB with no tuner gain. My filter ...
user3696623's user avatar
1 vote
2 answers
75 views

Phase detection accuracy with USRP N210 and CBX-40

I have designed a simple TX/RX system in GRC with a single USRP N210 and CBX-40. I am transmitting sinusoidal signals at various frequencies within the 2-6GHz range and detecting the amplitude and ...
Fati's user avatar
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3 votes
2 answers
218 views

Antenna reciprocity how does an antenna increase receiving range?

According to Wikipedia antennas are reciprocal unless they're constructed of nonreciprocal materials. There are a multitude of mathematical formulas which unfortunately I'm unable to understand due to ...
icyli2's user avatar
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10 votes
3 answers
3k views

Would it be possible for a software-defined FM receiver to demodulate two signals on the same frequency?

When two FM signals are transmitted on the same (or about the same) center frequency, either you hear only one or you hear that noise I'm sure most of you have heard. Would it be possible for a ...
Someone's user avatar
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5 votes
2 answers
3k views

Why do Baofeng radios have such poor reception reliability?

What is the nature of Baofeng radios' poor receiver performance? This brand of handhelds has somewhat notoriously poor receivers. I hadn't noticed this much when using them for short distance simplex ...
natevw - AF7TB's user avatar
2 votes
2 answers
529 views

What are best practices against spurious frequencies (birdies) in the superheterodyne design?

One problem I observe with my homebrew superhet receivers/transceivers is the constant presence of several "birdies". From what I know this happens due to the great sensitivity of the ...
Aleksander Alekseev - R2AUK's user avatar
2 votes
0 answers
244 views

Why the Receiver Sensitivity theoretical value doesn't match its experimental value when using USRP B200mini in GNU Radio?

I'm using a USRP B200mini SDR card for my GNU Radio energy detector project. I wanted to measure its Receiver Sensitivity ($RS$) experimentally and compare the experimental value to the theoretical ...
HadK's user avatar
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1 vote
4 answers
1k views

Does an RF amplifier allow us to receive a signal from further away?

From my understanding a RF amplifier boosts the transmission power of your antenna, this will in turn give you a higher gain. However I've read that this only will give you a further "...
icyli2's user avatar
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2 votes
1 answer
705 views

Performance gain when turning off CTCSS/DCS?

By turning of CTCSS/DCS can there be an increase in performance*? *Performance: Battery life Latency Range Voice quality From what I understand CTCSS/DCS is extra work for the IC inside the radio. ...
user160357's user avatar
0 votes
3 answers
132 views

How to transmit computer audio to a wireless microphone receiver? [closed]

I'm currently trying to broadcast my computer's audio output to a wireless microphone system receiver so that I can accompany my school's coming presentation with music. The frequency range is 480-598 ...
user21397's user avatar
0 votes
1 answer
103 views

Frequency division multiplexing FM Radio stations

Can someone help me with this I'm confused on what it is supposed to look like?
Dan's user avatar
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12 votes
1 answer
3k views

What is a "roofing filter"?

What are roofing filters? Are there different kinds of things that are called roofing filter? Why would a circuit or component be called a roofing filter instead of just a IF bandpass filter? Why ...
hotpaw2's user avatar
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5 votes
2 answers
645 views

Phased array (rx only) with separate complete receivers

Is it possible to have a network of separate (but co-located) 'receivers' (antenna + adc) act as a phased array receiver? Supposing one can get very precise timestamping on each receiver, couldn't all ...
Touisteur EmporteUneVache's user avatar
2 votes
0 answers
109 views

IF derived AGC: how to choose the best block diagram?

I've built several transceivers in the past. I never implemented IF derived AGC, so I decided to give it a try in the next project. I choose to build a superheterodyne receiver, which will probably ...
Aleksander Alekseev - R2AUK's user avatar
-1 votes
1 answer
75 views

Acoustic Communication issues [closed]

[![I've attached schematic, I am connecting transducer directly to that header pins on receiver side. On transmitter side I am connecting op-Amp to boost voltage to +10v -10v.][1]][1]I am working on ...
Gaurang Solanki's user avatar
0 votes
1 answer
141 views

How to analyse the distribution of the noise being received by my RTL-SDR device?

I'm very new to RTL-SDR and signal processing in general, but have managed to get my device (NOOELEC NESDR Mini) working and data into Python (via the pyRTLSDR library). I am able to output a complex-...
Kris's user avatar
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0 votes
1 answer
93 views

How to Measure Bandwidth using just your receiver [closed]

How do you measure the two to one bandwidth of an antenna using a Bird Watt meter? Tom Planer KJ9P
Tom Planer's user avatar
1 vote
2 answers
131 views

Can a smartphone with single antenna receive signals modulated by different schemes

I am working on a system whereby a smartphone may receive signals simultaneously from different sources. As we know, the fading and pathloss will make the transmitters send their traffic with ...
Yukinari's user avatar
0 votes
3 answers
862 views

Where can I find a service manual for the TECSUN PL-660 to replace the failed circuit board flex cable myself?

Diagnosed three nonfunctional TECSUN PL-660 radios (one from eBay Anon-CO, and two from Amazon) where can I find a service manual to replace the failed circuit board flex cable board assembly part? ...
JWC1976's user avatar
3 votes
1 answer
130 views

Why is my experiment to produce 3rd order harmonics by saturating a receiver not working

I've been trying to devise an experiment to produce a third order harmonic in radio receiver that's been saturated, but I'm not seeing the expected results. My understanding of the theory is that when ...
Frank's user avatar
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3 votes
1 answer
417 views

Globar resistor repair or alternative(s)?

I am restoring a Hallicrafters S-120 receiver and when trying to unsolder the wires, from the electrolytic capacitor, I noticed that one of the terminals of the Globar resistor (880-100 Ohm / 023-...
essential555's user avatar
0 votes
2 answers
293 views

Receiving range of ham radio on SSB with a portable radio receiver

I'm learning about shortwave listening. I want to listen to amateur/ham radio on a portable radio (eg a XHDATA d-808) with SSB, I hear SSB is the main place hams would be on. I know it's hard to give ...
Emma32's user avatar
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2 votes
1 answer
366 views

Receiving shortwave frequencies from different countries (e.g. North Korea)

This question may be a little strange, but how can I receive radio waves from a country like North Korea (when I live in Poland)? I am interested in this topic, but I don't have that much knowledge. ...
MagicMan's user avatar
0 votes
2 answers
110 views

universal 433 MHz test lamp (receiver)

I was wondering whether quick testing of various commercial ISM band transmitters for operation can be accomplished with some sort of off the shelf universal receiver which only turns on a led upon ...
kellogs's user avatar
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2 votes
3 answers
112 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 ...
sumer fattoum's user avatar
3 votes
2 answers
271 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 ...
fiacobelli's user avatar
3 votes
3 answers
261 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 ...
Aleksander Alekseev - R2AUK's user avatar
4 votes
1 answer
160 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 ...
hotpaw2's user avatar
  • 13.3k
3 votes
1 answer
241 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 ...
Caoimhin's user avatar
5 votes
3 answers
652 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 ...
Steven's user avatar
  • 205
2 votes
3 answers
493 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 ...
Ramanda Nvl's user avatar
1 vote
2 answers
769 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? ...
hotpaw2's user avatar
  • 13.3k
0 votes
2 answers
95 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 ...
hotpaw2's user avatar
  • 13.3k
3 votes
1 answer
140 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?
hotpaw2's user avatar
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2 votes
1 answer
241 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,...
TEQATAR's user avatar
  • 43
4 votes
2 answers
627 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 ...
Andrew's user avatar
  • 3,685
5 votes
2 answers
839 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 ...
user avatar
2 votes
1 answer
123 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 ...
hotpaw2's user avatar
  • 13.3k
0 votes
1 answer
104 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 +/...
thegamebusterpl's user avatar
2 votes
1 answer
141 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 ...
Doe John's user avatar