Re: [Discuss-gnuradio] USRP need antenna?

[Suvda Myagmar]

Eric Blossom wrote:
> As far as I know nobody has said anything about not needing an
> antenna.  You need something.  Try a 3 foot long piece of wire.  
>
> For the broadcast AM band, longer is better.
>
> A cheap "FM dipole" works great for the FM broadcast band.  By "FM
> dipole" I mean those really cheap T-shaped wire antennas that came with
> your stereo.  They're typically available at the local drugstore for
> about $3.  Don't bother trying RadioShack, they don't carry them, only
> the $20 amplified antennas that you don't need.

I tried 2 different antennas. First, tried with FM/UHF tv antenna that 
has 2 extendable wires and one loop. Had to cut off the input connector 
of the antenna and just stick the bare coaxial wires in one of the RX 
A/RX B jacks on the USRP receiver board. I could tune and hear only one 
FM station among several; and even that one with a lot of noise.

Next, tried FM dipole that looks like T shaped tape, the one you hang on 
wall. This one had 2 parallel inputs, each flat U shaped, I guess 
they're supposed to be secured between nut and bolt. I cut them off, 
stuck bare wires in the receiver jacks. Nothing, can't tune to a single 
AM/FM station.

These antennas I assume don't have any gain control. I read on Ettus 
website the following:

-----------------------------------------
Can I do interesting things with just a USRP and BasicTX/BasicRX, but no 
RF frontend? Do I need a separate RF front end to capture, say, CW or 
phone transmissions in the amateur bands? Or can the BasicRX fill that role?

For reception you would need to add gain and filtering in front of the 
BasicRX daughterboard. This can be done pretty easily with MiniCircuits 
parts, or you can use the 10.7 MHz IF output of common scanners and 
receivers. The BasicRX board will handle signals up to around 100MHz 
directly. For higher frequencies you'll need to downconvert.
--------------------------------

It seems like I need an antenna with gain and filtering... Where do I 
get those? I'm totally illiterate in harware, electronics areas.

Many thanks

-suvda