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]
February 17th, 2007 at 8:00 pm
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
December 10th, 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!
July 2nd, 2008 at 5:33 pm
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.
December 13th, 2009 at 1:05 pm
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/
February 22nd, 2010 at 8:20 am
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…