Small Hidden Antennas for Indoor Amateur Radio Episode 1

If you live in a flat with no garden you can still receive some reasonably distant signals using small indoor antennas or disguised antennas on the balcony. Some info too on how to reduce noise coupled from computer to radio. This series is intended to continue showing developments that I make along the way.

Keywords: FT4 FT8 Xiegu X6100 antennas HF amateur radio noise interference wsjtx wsjt-x sdrplay hidden camouflage small indoor clandestine

[ohaya]

What an excellent video! Fantastic demonstration! I also live in a flat and I have a lot of metal all around my balcony. I have a temporary setup and managed to hang a dipole for the 10 band similar to an inverted L but much more crooked. The radiating element is somewhat parallel to the balcony floor but not fully stretched. The one connected to the braid falls down parallel to the coax but each time I set up the dipole I fiddle with it to ensure the smallest swr. It is this non radiating element that I keep moving to control the SWR. It almost never the previous position.

[jeff-]

You probably said it somewhere in the video but just a note that random wire doesn't mean a random length of cable. Google will show some handy spreadsheets for lengths of wire to avoid... basically resonant frequencies and their harmonics. Thanks for the vid / ideas.

[davidwilcox]

I appreciate you and your willingness to experiment. In my 63 years of ham radio I know so many who would just give up with this wonderful hobby when living in a flat in the city…. Too much noise, RFI, and few contacts (they give up too easily). Bill Meara of Soldersmoke fame lived in central London for a few years and enjoyed his hobby with hidden antennas and showed us how on his podcast. Keep it up. Dave K8WPE since 1960

[sputniksam]

RE: Not receiving any output on your laptop. The most likely cause is because your laptops clock is not set to the correct time. It only needs to be off by a few seconds for this to happen. As you're using Windows it's easy to fix, simply left click your clock on the bottom task bar, select "Date and Time". A window will pop up and in that window will be an option to sync your computer clock with a time standard. Job done.

[patriot]

May I offer an option for the red lid. Drill a small hole dead center of the lid, put something that can hold it in place to make it easier to hold.

[ELMI]

Hi Simon. Have you checked the laptop's clock is accurate? (Are you running a time sync program?) This foxed me too when I moved from my main PC to using an old laptop and I eventually found the time was out by a few seconds on the laptop. As soon as the time was synced, signals were then decoded.

[DAVIDGREGORYKERR]

If you lived on the top you might be able to put an antenna on the roof of the block of flats.

[cthoadmin]

Simon, you never did say what's in the peanut butter jar... Will you be bold enough to try transmitting into the balcony antenna? 73 VK4QP.

[GVFY]

You put a tuneable loop antenna on the back of an antenna WHY??? You don't need effectively TWO tuners. Loop antennas have a VERY high Q and so you will only see 6-8Khz bandwidth on an SDR waterfall display. G7VFY.

[davidwilcox]

All very interesting and over the years I have learned if you are using low power just load it up. Even greater than 3:1 SWR won’t kill your low power transmitter. Get on the air and see who hears your signal. This is HAM radio and over the years bed springs, aluminum screen windows one slider door screens and emit and receive a signal. Dropping an invisible small diameter black wire straight down works well to. Living in a flat like you your biggest problem will be radio frequency interference from all the electronics in each flat. Great video. Just encourage others to JUST DO IT!

[Steven-rext]

I've hidden cb/ 10 meter in flag poles. Still Hawkeye the HOA PRESIDENT. NEVER GIVES UP. SO I CARRY a roll of wire. Mainly for my recivers. this serves me well. As I deploy it at my will. Tks fer pointers odn-1

[TRTelos]

Great audio, I thought it was raining at mine.
At 120ft asl in a tower block with a tuner and 5 watts, on a plastic window frame containing 3 metal window frames I connected the earth to one window on the left and centre of coax to metal window on the right, from Manchester to Europe at time of great signals on 10m no problem back in 2000.

[rbc]

Awesome video Simon, thank you. This really shines the light on how important getting that noise floor down and how to do it. One question, how do you like the Xiegu X6100 radio? I will be purchasing my first radio soon and this seems to fit the bill at a reasonable cost. Is there different one you may purchase after using this one for a bit?

Again, thanks for the great video.

[GeoNJRJ]

Maybe a 9:1 Balun would help? Good video. Thanks! N0JRJ

[seymourpro]

Your loop antenna could be adjusted by fitting a long piece of plumbing pipe to the knob, or even moulding a heated pipe round the knob -like a box spanner.

[GordieGii]

I would use a long plastic rod (or straw) to keep my hand away from the loop.

[SimonBlandford]

I also live in a flat except with no balcony. Although there is a metal rail outside the window it is, as expected, electrically earthed. I have managed to work some stations in Europe on 5W/FT8 using the Wizzloop antenna next to the bedroom window. Managed to cross the Atlantic with WSPR and FT8 spots (not QSOs yet).

I see the Faraday-cage QTH situation as a challenge. Trying to make a radio contact from inside a flat is fun! One day I might even manage a voice contact on another continent.

[DarrellLarose]

Could you use a long rod or dowel to tune the antenna.

[GVFY]

The noise is probably coming from the screen inverter for backlighting.

[drz]

Just a thought - those styrofoam pool tubes - some are hollow, some solid - cut one to fit over that sensitive knob - and maybe, hopefully, the styrofoam will act as an insulator and allow accurate tuning