Indoor antenna for 7 Mhz
I’m looking to setup a hidden / indoor antenna, and i’ve found a couple of interesting articles on hidden / stealth antennas
This small antenna can allow hams which lack space to install an antenna for 40 meters. This project has been originally produced by F6CYV. I’m going to test this antenna in the coming weeks. I will try to setup this inside my balcony.
According to his experience, using it form inside the apartament, european singals are all very readable, he has worked over 150 countries.
The antenna is made of 2mm wire.
The 2 coils are constituted by 18 turns of 2 mm wire, distance of tunrs is also 2 mm.
The diametre of the coils is of 7,8 centimeters.
The Feed of the dipole is done with a 75 ohms tv coaxial cable.
A 1/1 balun would be recommand for a correct feed of the coaxial cable to the dipole.
It is not necessary to use a coupler, it is enough to set the length of both extremities of
the dipole in order to have at 7.050 mhz a low SWR, and especially to pay attention what the lenght of the 2 sides of the dipole to be identical.
[tags]antenna,ham-radio,amateur radio,HF antenna[/tags]
This antenna could be interesting. You have any experience, with this? i looking for antenna for my ft-897, i live on condominium, i have antenna of movil for 2 metres, but i don´t hear any station on hf, and is very sad for me, congratulations for your article and you have a good day
That’s a cool one, but what are teh formulas you’re using to design this antenna? Metric copper wire est impossible to find in North America!
I am having lots of fun with a FT-897 and 27 feet of wire using a tuner. It gets me out down to 40 meters very well. It will load up on 80 meters, but reports are usually weak.
The overall wire length is 27 feet, so it’s 4 feet up from the tuner to the ceiling, and 23 feet straight along the longest distance available in my small apartment on the second (top) floor of the wooden building.
When using, I let the wire droop in the middle about 4 feet down from the ceiling, since that is where the most radiation seems to be, and I want it to be away from material.
I can tell on PSK work with automatic monitoring stations, that I hear only half of the stations that excellent antennas hear on 20 meters… but it is still fun.
For 10 meters I use an Inverted L antenna which seems perfect for an apartment. On the second floor height the feedpoint impedance is close to 50 ohms, one leg is out of the way on the ceiling, and the other leg hanging straight down towards the floor (about 6 inches away from the wall) is out of everyone’s way also. It also the strongest vertical polarization I have found compared to an inverted V, and dipole.
hallo its nice articles for me but my problem is alittle dificult to find 75ohm coax good quality usualy in market sale 50ohm can it if change to50 ohm and about ballun 1/1 or any kind thanks 73 nice day regards from west java indonesia/
I’m planning to build a shortened 80 meter dipole and feed it with 450 ohm ladder line. The antenna will look similar to a folded dipole with the center not connected. My plan is to make the antenna about 75 feet long for the main wire and fold back 25 feet on each end. I’m planning to use small diameter PVC pipe for insulators for the folded part and then use rope to make up the difference in the middle. Therefore, the antenna will ultimately only be 75 feet long and look to my antenna tuner as though it was 130 feet or more with the linear loading of the folded back wire.
My 73…
Yeah, it looks compact and suitable for ham living in space limitted apartment. My idea is to put up the design outside window (at least 3-4 meters away from wall) and use an ATU for 20/15/10 meters. 50 ohm cable seems okay and a 1:1 balun is a must. 73 from Shanghai, China.
Please, I want a picture of antena of WA9VEE Says;
I am having lots of fun with a FT-897 and 27 feet of wire using a tuner. It gets me out down to 40 meters very well. It will load up on 80 meters, but reports a ….
can you sent me ??? or sent the e-mail from WA9VEE
Tks 73 from PU2YCA Antonio Carlos – Campinas Brasil
if possible more details for this antenna?
RE: Pat says:
December 10, 2007 at 12:04 am
That’s a cool one, but what are teh formulas you’re using to design this antenna? Metric copper wire est impossible to find in North America!
PAT: 2mm is the same size as 12 gauge copper wire in America. Can be bought at most home centers like Lowes or Home Depot or ACE hardware etc. It is common wire for housing construction.
RE: Pat says:
December 10, 2007 at 12:04 am
That’s a cool one, but what are teh formulas you’re using to design this antenna? Metric copper wire est impossible to find in North America!
PAT: 2mm is the same size as 12 gauge copper wire in America. Can be bought at most home centers like Lowes or Home Depot or ACE hardware etc. It is common wire for housing construction.
Hope this didn’t double post – having trouble with the symbols.
how far off the walls is the antenna. i have tried similar but i need it as close as possible to the walls and the walls are concrete. thanks