Indoor Antenna, in a flat

[M6AUK]

This is my daft question of the day....

I live in a 3rd floor apartment, but I am a 1/2 wave of 20m up in the air, give or take a few cm's.

My hallway runs from one end of the apartment to the other, and would accommodate a 10m EFHW

The building is brick walls predominantly, but the floors and ceilings are solid concrete with (I would imagine) steel reinforcements running through them.

Aside from the obvious limitations of an indoor antenna (electrical, other rfi etc) would the antenna see my floor as 'ground' or would it behave as if it were in actual fact 10m off the actual ground? Would it predominantly be NVIS, or would it radiate at a typical DX angle?

I wouldn't expect great things from it, obviously.

I'm just trying to find ways to annoy the wife...

[Tigersaw]

I would imagine the building would behave as if it were radials or artificial ground plane, so the 10m height is lost.
You could dangle it out of the window as a vertical though.

[M6AUK]

You could dangle it out of the window as a vertical though.

I've got a very tall and 'branchy' Beech tree approx 15m away right outside my window, I've been putting EFHW to it for quite some time. I need to be stealthy so I don't upset the Managing Agents (I own my flat), but thus far no-one has complained. Problem I have, is I can't leave them up, I have to dismantle them when I am finished. Hence why I wanted to play with some wire indoors. I do have a mag loop I use indoors too, and that performs very well. As for dangling out the window.... I did that, once. My neighbour downstairs wondered what the wire was... I had visions of him grabbing hold of it just as I keyed up.... so I decided to not go down that route, just in case.

[Tigersaw]

I did have success with a loft dipole once, USA on 10m when the conditions were right. I used a co-ax aerial, double bazooka. Ends up being a bit shorter and wider bandwidth.

[14CS06]

Hello



1977 Indoor CB Antenna

For the woman shown in this picture, from an ad in the May-June 1977 issue of Elementary Electronics, the CB was probably her connection with the outside world, and her social life probably revolved around the good buddies she met on the air. She was probably a REACT member, and used her CB to help motorists in need.

But she had a big problem when she moved into a new apartment where outside antennas were not allowed. Fortunately, Hustler came to the rescue with this indoor CB antenna, dubbed the “Homing Pigeon.” According to the ad, this antenna was the answer to operating the CB from any location, such as a condominium, office, home, apartment, or motel. The spring-loaded antenna required no installation, and was supported by the floor and ceiling “like a pole lamp.” According to the ad, the range was “equal or superior to better mobile installations.”

Of course, the construction of the building probably played the biggest factor. Such an antenna would probably work well from a wood-frame house. From a building made of steel, it probably wouldn’t work quite so well. In this installation, placing the antenna next to the ductwork probably didn’t help. But this was probably outweighed by getting it next to the exterior wall, and she probably got out pretty well in that direction.

From : http://onetuberadio.com/2017/05/28/1977 ... b-antenna/

Manual







@+
Claude

[ch25]

Yo really want to radiate RF directly to your body?

I'm just trying to find ways to annoy the wife...

Get rid of her. Problem solved.

No balcony? Put vertical dipole made out od 2 tank whips outside the window on some boom.
With a tree outside you could hang regular dipole for 10m. Thin wire with some RG-174 shouldn't be visible too much.

Chris

[Werthers]

Some places you can get away with having an indoor antenna but most of the time performance is pants and not worth doing half the time. A mag loop is great for HF if nothing else can be used.