Reception poor. Antenna or just a cheap dongle?

[Dave B]

I bought a NooElec NESDR Mini 2 SDR & DVB-T USB Stick (RTL2832 + R820T2) here. I installed gqrx from the Ubuntu 14.04 repo, then removed that and added the repos to get the latest version. It works, but I'm only receiving broadcasts with strong signals. I can't get any of the WWV stations, but am able to get some strong broadcasts down to about 2Mhz, some CB radio traffic, a few FM stereo channels, and the local airport a few miles away. I tried a different telescoping antenna, and even a wire strung along the roof which worked well for a SW radio. There's no errors when run in a terminal. There does seem to be a high level of background noise almost across the entire spectrum unless the gain is turned almost off. Is this the norm for these $20 dongles? 

[David Ranch]

Your RTL dongle is actually a decent receiver but those included antennas are *garbage*.  So what to use?  The best antenna for you will depend on what you want to listen to.  Install a Ham radio antenna if you want to listen to various amateur bands (antennas that are resonant on those frequencies).  Want to listen to broadcast FM stations, there are many antennas for that too.  All of these antenna types won't require you to buy anything if you don't want to as many are quite easy to build yourself.  If  you really want to receive well on a lot of spectrum, I would recommend a few things:

   - Get your antenna outside:  Any antenna installed outside your home will receive a LOT better than then best antenna running inside your home

   - Use a discone antenna for maximum received frequencies

   - The farther away your antenna will be from the RTL dongle, the better coax you should use.  The higher the frequency (>400Mhz), it's even more critical to use short coax or use very good / low loss coax


--David
KI6ZHD

[Dave B]

I'm going to pick up a Discone Wide Band Antenna. Do you think quad shield RG-6 cable would work (I have 1/2 spool of it after rewiring my CATV) or should I get some RG-59? Since this is going to be RX only is there any coax or antenna matching I need to do? Back in my CB days we used to fine tune the SWR by trimming the coax.

Anyone try a FDM-DUO SDR transceiver? It's expensive but looks like a nice rig.

[David Ranch]

It all depends on your budget, what frequencies you want to monitor, the length of the coax run, what you can route through your attic vents, etc.  Check out some of the coax loss charts and compare say RG6 to say LMR400 or 9913:

   https://www.google.com/search?q=coax+loss+chart+RG6+LMR400&ie=utf-8&oe=utf-8

Overall, RG6 is not great, especially for high frequency stuff.,
--David
KI6ZHD