Newbie questions about antenna
Hi All,
I’m just starting out with SDR and bought an RTL-SDR v3 dongle from RTL-SDR.com. I would like to ask some questions about a suitable antenna for it. I’ve spent many hours on forums and web sites but at this point, I am overloaded by information which ranges from informative and helpful to contradictory and confusing. I know that there is no “best” solution but I’m hoping the answers to my specific questions will guide me to a suitable compromise. So far, all I've tried is dropping a few meters of unshielded wire out of a window.
First the constraints.
I live on the 2nd floor of a rented, two-storey, brick-built terrace apartment block surrounded by trees front and rear but there is nowhere to mount an outdoor antenna mast. There is no balcony. Finding a good RF ground is also a problem. There is nowhere to drive a ground rod into the earth and no copper water pipes in the apartment – only stainless. I’m not sure if they would be any good as an RF ground. The building is as you'd expect, awash with RF noise from PCs, routers, smart wi-fi devices and what have you.
My idea
What I thought I’d try is a long PVC telescopic pole 3 meters or so in length with an SA0RDT type active mini-whip on the top for HF. The mast would be shoved out of the window at an angle of about 30 degrees from vertical and will be long enough to clear the roof of the building. It can be retracted when not in use. The window is in the bedroom separated by a brick wall some distance away from my PCs and other sources of RF noise. If the mini-whip proves unsatisfactory, I can easily try other types of antenna (active or passive) on the same mast eg passive discone, active or passive loop etc.
My questions
a ) Is it a good idea to mount the SDR dongle as high up and as close as possible to the active antenna connected by 6 inches or so of coax? Then a long (active?) USB cable can be used as the downlead to the PC. It would run through a small hole in the wall at floor level to the adjacent room to the PC. Is this a good method to reduce RF noise pickup?
b) The RTL-SDR.com dongle has an on-board Bias-T circuit which is activated by software. Is it better to use this and dispense with the separate Bias-T module supplied with the antenna or should I leave this inactive and use the supplied one? Or doesn’t it matter?
c) I’ve been told that a steel plate or steel mass of some kind can be used as an RF ground. Can I have some examples of the sort of thing one might use in a flat? Would a small steel filing cabinet for example, be any good?
Apologies for a bit of a long-winded post. If you've read this, thank you. I'd be grateful for any help and advice to help guide me to the optimum solution given my less than ideal environment.
Trevor