Re: [Discuss-gnuradio] to prevent damages

[michael taylor]

On 9/27/06, Brian Padalino <address@hidden> wrote:
> It might not be a bad idea for Ettus Research to also stock some other
> items such as SMA cables/adapters/attenuators.

Attenuators might a good idea. I think a model to match the 100mW
transmitters would be Mini-Circuits' VAT-15 (50 ohm, SMA, 1W, 15dB,
usable up to 4GHz) if I've done my loss calculations correctly
<www.mini-circuits.com>. A 9 or 6 dB for the BasicTX should be  usable
if I haven't messed up my calculations.


> It might also be handy to have some nice block diagrams with max power
> recommendations and recommended attentuations for cabled setups as
> well as a table in the Wiki with such recommendations.

Here is what I think the calculation is:

transmit power converted to dBm (1 dBm == 1 mW) minus the attenuator
loss = output power in dBm.

E.g.
 100 mW -> 20dBm
 20dBm - 15 db att = 5 dBm
 5 dBm -> 3.2 mW

So if the receiver can handle 3.2 mW input, this would be adequate
attenuation. Off hand I don't know what is acceptable input power
range.

dBm ref: <http://en.wikipedia.org/wiki/DBm>

> That might save some of the more software oriented people from burning
> out their hardware without intentionally doing so.

Agreed.