Near-field coupling can cause excessive power coupling from a transmitting antenna into a receiver. This video describes near-field coupling and shows how to calculate its effects. An empirical approach is described to establish whether near-field coupling is a possible issue in your installation. Methods to prevent potential damage, if required, are suggested.
You can download the slides used in this video from: https://www.sdrplay.com/resources/NearFieldGuide.pdf
See also this practical demo using an MFJ T/R switch: https://youtu.be/M4B0ffxQgHY
Links to sites mentioned:
Wiki: https://en.wikipedia.org/wiki/Near_and_far_field
Unwanted coupling: http://www.w8ji.com/antenna_coupling.htm
Everything RF: https://www.everythingrf.com/rf-calculators/antenna-near-field-distance-calculator
Rohde-Schwarz: https://www.rohde-schwarz.com/us/applications/field-strength-and-power-estimator-application-note_56280-15837.html?fbclid=IwAR3KKnU1HHBdka9EwoMrAyJ1W4I-A9NLIc_V1JeAPf7JtuGc9LJhJuhYEKE
2 FAQs:
Why is the RSP1A blue and not black? The blue RSP1A used in this video is an RSP1A case with no internal metal coast for RF shielding - it was used to show the worst case scenario. The black cases are coated with a metallic coat which has a small impact particularly at UHF and above.
Why are RSPs more delicate than many other receivers with regards to damage from RF power? Because the RSPs have to cover operation up to 2GHz, it is not possible to use the more rugged protection diodes used in HF rigs for protection - their parasitic properties would degrade performance at UHF and above.
This is one of many video guides from SDRplay - makers of the RSP family of SDR radios. See the full list of SDRplay videos and applications documents on: https://www.sdrplay.com/apps-catalogue/
The RSP family of SDRs from SDRplay cover 1kHz to 2 GHz with no gaps and give up to 10MHz spectrum visibility.
SDRplay is a UK company. The RSP SDR receivers are made in the UK and can be purchased for worldwide delivery directly from http://www.sdrplay.com/ (click on purchase and select your country to view shipping costs) or you can buy from any of our worldwide resellers listed here: http://www.sdrplay.com/distributors/ Many of the resellers offer local free shipping and/or local language technical support.
The SDRplay YouTube Channel is: https://www.youtube.com/c/SDRplayRSP