One of our customers recently wrote to us with the following thoughts regarding locating the SDRplay RSP2 a long way from the PC. He wrote
“An issue for many RSP2 users is the cost of long lengths of LMR-400 and LMR-600 or equivalent cable which costs around $115 USD for 50ft. So if the antenna is around 50ft from the PC running SDRuno or SDR Console, then it is much less expensive to locate the RSP2 at the antenna and use a 50 ft active USB 2.0 extender cable from the PC to the RSP2. The 50ft USB 2.0 extender cable costs $11.72 USD.
I tested a 50ft USB 2.0 480Mbps extender cable (please note – the url link previously posted is no longer available – July 15th 2018 update)
This cable works great in the application I have. The one at the link above will support up to 250mA and works off of the power of the PC USB port (no external power supply). So it will run the RSP2 (170mA) and up to 80mA on the bias T at the same time. Also, you can use a standard USB cable with it. I am using a 10ft USB cable with it for a total distance of 60ft.
This is currently being used for reception of GOES 13, 15, and 16 signals at 1.691 to 1.694 GHz with no perceptible difference in reception. I suspect it will work well regardless of the reception frequencies of the RSP2 since it appears to have good shielding, but I have not tested across all frequency bands to see if the USB cable and data signals impact reception. I thought your customers might like to know about it though, since this has the potential to provide a low cost solution to displace the use of expensive coaxial cable.
Consider that the cost savings for a 50ft cable alone almost pays for another RSP (though the RSP needs to be placed in a weatherproof enclosure). “
Regarding outdoor operation, the RSP2 is designed to operate from 0C to 50C, but may possibly work down towards -10C. So for many locations there is potential to locate the RSP in a waterproof container out at the antenna. Using a $12 extender for USB2.0 instead of a cable and driver amplifier is a considerable cost savings. Let’s say 65ft of cable is needed. So you could use a $12 50ft USB2.0 extender plus a 15ft standard USB2.0 cable $7. A $19 solution locating the RSP2 at the antenna. By comparison, using 65ft of LMR-600 is around $120 and then a $140 line driver amplifier is needed. This is a $260 solution to the same issue, a $241 difference. The point being, for the difference in cost, it saves more than enough to buy another RSP2. So it potentially becomes cost effective to then use an RSP2 for each antenna when applied to GHz applications.