Monday, July 7, 2014

A set of wideband antennas for the FunCube Dongle Pro(+), hackRF, bladeRF and RTL-SDR

When I got my Funcube Dongle Pro, I was looking for a suitable set of antennas.

Since it covers such a wide bandwidth, finding a single antenna that covers the entire bandwidth is hard.

Log-periodic antennas seem to be the most suitable wideband antennas. (They are however directional, which can be good or bad, depending on the application) However, they get impractically large, and as a result unobtainable for frequencies below about 400MHz. For these frequencies, the only practical options seem to be telescopic antennas (which can be tuned for a frequency by differing the length that is expanded) or scanner antennas.

I ended up ordering this set:

I have since acquired a RTL-SDR dongle. The dongle that I have has a TV-style 75-ohm input connector, as opposed to the 50-ohm SMA connector on the Funcube dongle. Ideally, a balun would be used to match the impedance, but as a minimum, some cables can be made up with the relevant connectors at the ends. I found this video with information on building your own, if you need the increased sensitivity that a properly matched antenna provides. Some other dongles, like the one from hakshop, a random one from Amazon and the NooElec one has MCX connectors, which seem to mostly be 50-ohm.

I have also ordered a hackRF, which has a higher maximum frequency, which requires another antenna. I'm planning to acquire this one. (The ANT500 antenna that is available for it seems like a suitable replacement for the telescopic antenna). My planned antenna set for it:

Another transceiver that is available is the bladeRF. It covers 300MHz - 3.8GHz, but it has a higher sampling rate than the hackRF (and a FPGA). An upconverter that allows for lower frequencies are also available. A nice antenna set for it is:
For the low end of the range, if you have the space, also look at the scantenna. It covers 30MHz - 1.3GHz (with several gaps). (It might not be safe for transmitting (bladeRF and hackRF)). (Full specs)

This discone also seems like a great antenna if you can install an outdoor antenna. It can handle transmitting up to 200W on the 6m, 2m, 70cm, ~1.3GHz ham bands. Reception is listed as 25MHz - 1.3GHz

I would also recommend a full set of converters, covering different types of antennas. Some examples: