How a diversity radio receiver works - Page 1
Forum section: electronics / rf-microwave

author: prabhatkarpe4
author_rank: Contributor
timestamp: October 25, 2024, 01:04:21 pm
content: I need to know how a diversity radio receiver works and if it can mitigate fading then why most radio receivers are not having this technology?

author: VinzC
author_rank: Frequent Contributor
timestamp: October 25, 2024, 01:09:12 pm
content: Quote from: prabhatkarpe4 on October 25, 2024, 01:04:21 pmCare to elaborate on that premises of yours?(especially since that claim somehow implies that you already have an idea of how this all works)Quote from: prabhatkarpe4 on October 25, 2024, 01:04:21 pmYou're aware complexity comes at a cost, right?

author: xrunner
author_rank: Super Contributor
timestamp: October 25, 2024, 01:09:52 pm
content: Why don't most receivers have it?Depends on the situation that the receiver is designed for. For example simple radios for "consumer" use, i.e. AM or FM broadcast band, don't need that.People using them to listen to local AM or FM stations will not experience fading. It's not a problem.But if you are a "DXer" and want to try and pick up distant stations for fun, then you might want a more advanced receiver.

author: wasedadoc
author_rank: Super Contributor
timestamp: October 25, 2024, 01:52:21 pm
content: Quote from: prabhatkarpe4 on October 25, 2024, 01:04:21 pmYou already got an answer about diversity reception in a previous topic you started.https://www.eevblog.com/forum/rf-microwave/how-to-mitigate-fading-of-sw-reception/msg5677789/#msg5677789

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: October 26, 2024, 07:45:15 am
content: Quote from: prabhatkarpe4 on October 25, 2024, 01:04:21 pmA diversity receiver setup uses two identical receivers, each is connected to a different antenna. You can have polarity diversity where one antenna is horizontal and the other is vertical, or you can have antennas spaced apart, for example when using a microwave link across a stretch of tidal water you can have the dishes as different heights so that when the direct and reflected (off the water) signals cancel each other out on one antenna, the higher (or lower) antenna will not have signals that cancel.In amateur radio terms only a few transceivers have diversity, the Icom IC-7610 is one example, another is the Elecraft K3/K4 when fitted with dual receivers. Those transceivers feed separate speakers, or the left/right earpieces of headphones, with the audio from each receiver so you hear signals swap from one side to the other. Commercially, receivers feed a single output and have their AGC lines tied together, so you only have the one combined audio output.It is important that both receivers (or receiver parts of a transceiver) are identical and are fed from a single oscillator, otherwise the phasing will be wrong.73 SJ

author: mr ed
author_rank: Regular Contributor
timestamp: October 26, 2024, 09:39:02 am
content: Digital diversity is done at baseband. Requires DSP to combine data streams and usually a powerful forward error correction scheme for each channel. Antennas to be spaced apart some factor of the working wavelength. Testing requires diversity simulators too. It gets expensive compared to a regular system design. Look up Rayleigh fading, MIMO channel coding and the Shannon limit and go from there. Satellite systems may use time diversity too (send 2 or more times) like for software updates which can tolerate relatively large delays. GPS and cellular systems CDMA uses code division to get data buried under the noise level. Many white papers to browse through.

author: iMo
author_rank: Super Contributor
timestamp: October 26, 2024, 09:53:51 am
content: At prabhatkarpe4:https://www.eevblog.com/forum/beginners/newbies-please-read-before-posting-24542/