Consultation on car radios and improve the sensitivity of my mobile radio

Thread Starter

Gustav2021

Joined Nov 26, 2021
1
Hello everyone, I'm new on the forum. I hope I am in the right place and section to clear my doubts. Otherwise, I apologize. (and sorry for my bad english). The query is the following, I wanted to clarify about why car radio has a much higher sensitivity than conventional receivers. Is it due to greater sensitivity in the electronics of the device? Or because of the good quality of the antenna they use on the roof? I have a Tecsun PL-360 receiver, and according to the technical specifications indicated in the instruction manual, its sensitivity in FM is 3 μV. Whereas my car radio has a sensitivity of 0.8 μV in the same band. From what I understand, the smaller the number of μV, the more sensitive the device is. On the other hand, I have seen handys for example from the Baofeng brand, model uv-r5, which in addition to VHF, brings the option of listening to commercial FM (65-108 MHz), whose sensitivity according to the manufacturer is 0.2 uV . My question is, because car receivers have a higher sensitivity than telescopic antenna ones? Is it because of its external antenna or is it because of the high sensitivity of the receiver itself? About the aforementioned handys, are they really more sensitive than the receiver of my car radio? Thank you very much in advance and I apologize if I am consulting the wrong section.
 

Yaakov

Joined Jan 27, 2019
4,023
Sensitivity is one parameter that bears on receiver performance. Alone it doesn’t tell much, and it can be manipulated. Useful sensitivity numbers will be reported in dB as some sort of SNR (Signal to Nose Ratio) related number.

A much more useful number is SINAD (Signal to Noise And Distortion) reported in dB. It is a systematic measurement that attempts to capture the effect of the entire receiver system on performance.

Sensitivity is one of two main parameters that are a concern, the other is selectivity. If you have a very highly sensitive receiver that can’t select the particular transmission you are interested in, it does you no good. Sensitivity and selectivity can be traded off, and manufacturers often choose to report things most apparently favorable to them.

So, look for SINAD numbers and selectivity figures to understand the actual performance of receivers, not one isolated number of dubious importance.
 

hoppyest

Joined Nov 20, 2018
4
Think of it like this: the Tecsun or the Baofeng will often be used in completely different circumstances to those in which a car radio will be used. A car may be a long distance from the radio transmitter or it may be close. It has to cope with huge variation, and sometimes attenuators are needed when the car is too close to the transmitter (hence a 'local/dx' switch on some models). A car radio may or may not have an effective antenna; the trend nowadays is to make antennas vanishingly small, therefore a more sensitive receiver is required for reasonable performance. The Baofeng radio is primarily a radio transceiver, and I wouldn't pay too much attention to the quoted sensitivity particularly as the antenna is not designed for the FM broadcast band and I doubt you are going to connect an antenna which would take advantage of the quoted sensitivity. The Tecsun is a receiver mostly designed for a domestic environment, where extreme sensitivity is less helpful than selectivity (as noted elsewhere) and overload performance. Sensitivity isn't the only factor, in many circumstances it is relatively unimportant.
 

Audioguru again

Joined Oct 21, 2019
4,129
ALL half decent radios have Automatic Gain Control so that the radio works very close or very far from a station.
The only radio I have seen with a manual local-distant switch is my Sony Walkman.

Most of my clock radios have the power cord as its FM antenna and a ferrite bar inside for AM.
 
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