KiwiSDR and recommendations for antennas and cables

[Miss Amy]

I recently bought a KiwiSDR and it's my first SDR so far. I was wondering, what antennas you guys recommendation for it and whether this recommended antenna is truly good for it (it was listed on the KiwiSDR site as a recommended antenna, but it's a bit pricey for me). I'm trying to find signals in the lower frequencies and I'd like an antenna that can catch them.

Also, what sort of cables would I need to hook up between an antenna and the KiwiSDR? I noticed the W6LVP antenna didn't seem to have any cables included (and I'm not sure if other antennas include them either) so if anyone can help me with that, that'd be great. If it varies between SDRs, that'd be helpful info too. Thanks a lot for reading!

 

[tech99]

I am not sure of the frequency range you are interested in, so can you be more specific? The main issue is that you do not want the antenna near computers, internet connections, electrical equipment etc due to noise pick up. Are you able to locate an antenna outdoors some way from human activity? You can use a coaxial cable to connect to the receiver.

 

[Miss Amy]

I'm talking about the HF range (30mhz-3mhz) and lower (since that is the range the KiwiSDR has). Unfortunately, I have to have the antenna inside my house and near my computer/internet connection. Would that be okay? Are general internet connestions HF and lower?
Oh, I'll try to find coaxial cables when I get the chance. Thanks!

 

[Tom.G]

A compromise for an antenna would be 26ft (7.9m) of wire strung out as much as you have room for; maybe in a loop around your room. That length is ¼ wavelength in the center (actually the geometric mean: √(3⋅30)= 9.49MHz) of the frequency band you are after. Since you have limited space and the frequencies are relatively low, just about any wire over a foot or so long will pick up something.

If you get to the point of wanting a serious antenna, it could be a half-wave dipole with its length ½ the wavelength of the main frequency of interest. The wavelength of a radio wave in meters is 300/frequency, where frequency is in Megahertz.

Cheers,
Tom

p.s. I'm assuming your 30mhz was meant to be 30MHz... 'm' is for the prefix 'milli' (1/1000); 'M' is Mega (1 000 000).

Trivia: And the 'H' is capitalized because it comes from the last name of Heinrich Hertz, a German physicist, after which frequency is named. (Hz used to be called 'cycles per second', or CPS)

 

[tech99]

Amy
The main issue is interference within the room. Maybe a balcony is available for a whip antenna? Or hang a wire from a window, or string it outside somehow? One thing to try is to carry an ordinary AM radio around the room and find a quiet area. In olden times a few metres of wire would have served, but now will pick up a lot of noise. Some people are finding that a compact (and expensive) active antenna located at a quiet spot is a solution. The loop antenna you mentioned is probably good but it is expensive. It is possible to make a tuned loop if you like making things and this will probably help a lot.