We have had quite a few people blowing up their RSPs over the past few months. Most people understand that there is a practical limit as to how much RF energy can be allowed to enter from the antenna socket to the delicate circuitry within. We try to make sure everyone understands that this must not exceed 0dBM ( 1mW) of RF power – a higher level of 10dBM (10mw) is acceptable for short periods. Most people know not to connect the RSP to a transmitting antenna.
However, what is sometimes less well understood is this:
- Disconnecting the USB while leaving an antenna connected which is presenting signals stronger than 10dBM to the RSP antenna input, does not help matters – if anything it makes it worse since the RSP is designed to have the USB connected to ensure the antenna switches are powered up in a known state.
- Tuning the RSP to a different part of the RF spectrum than the frequency of a potentially damaging transmission makes no difference whatsoever since the damage is caused by heating effects which will exist at any frequency (it’s not like adding a traditional attenuation as would be the case if you were mechanically switching in say, a chunky resonant LC circuit tuned away from the transmitter frequency).
Please take care to use proven protection techniques such as using protected RF or IF outputs from transceivers when using the RSP as a Panadapter, using a protection device or ensuring if connected to a dedicated receiver antenna that it is positioned such that the total energy received by the RSP remains below the oDBm level.
There are lots of discussions on our forum on the topic – just go to www.sdrplay.com/community/index.php and search with words like “protection” to find comments on the subject and links to recommended techniques.
Or join the Facebook group: https://www.facebook.com/groups/sdrplay and describe what you are trying to do, to get real advice from other users who have found successful ways of ensuring they don’t fry their RSPs.