What is the minimum antenna(s) I would need to pull in WWV (5/10/15Mhz)
and WWVB at 60KHz with my USRP with the Basic RX daughtercard? I was
wanting to look at decoding the BCD time code.
How about if I wanted to get my local airports ATIS at 126Mhz?
I am playing with some of the basic example code, either am_rcv.py or
the hf_explorer stuff and cannot get much accept local am stations (very
weakly) and I can get strong fm stations with the wfm example. I just
tried the little am antenna off an old stereo right now which is not
much and have even tried the kids slinky thinking to get something
longer to get a 1/4 wave or something close… I am not a ham radio guy
obviously.
Thanks!
On 12/7/06, Heiko J. [email protected] wrote:
What is the minimum antenna(s) I would need to pull in WWV (5/10/15Mhz)
and WWVB at 60KHz with my USRP with the Basic RX daughtercard? I was
wanting to look at decoding the BCD time code.
How about if I wanted to get my local airports ATIS at 126Mhz?
Short answer: It depends.
Slightly longer version: It depends upon three main factors 1) RF
frequency 2) distance from source (signal lost based on distance), and
3) atmosphere conditions (“propagation”) which is frequency dependent.
WWVB at 60KHz would normally use a loop antenna around a ferrite core,
similar to those found an AM radio. Depending on where you are (cont
US vs. Europe) a small AM loop antenna might work, or a large outside
antenna might be needed if you are in EU.
A VHF signal like 126MHz is roughly line of sight plus 5% (I think), a
1/4-wave vertical would normally work if mounted outside above a large
percentage of nearby buildings and terrain. So a 42cm (~16.5 in)
vertical antenna with a metal ground plane mounted at roof height
would likely work if you are “near” an airport.
A useful starting point is the ARRL’s Technical Information Service web
pages,
http://www.arrl.org/tis/tismenu.html. A copy of the ARRL Handbook
can also be an accessible reference for many common RF related
questions written in an accessible form (compared to standard EE / RF
engineering references), so if you plan on doing a fair bit of SDR
work I would recommend getting a recent copy.
-Michael Taylor, VE3TIX