Newbie Antenna Question

[KG4SSM]

good morning,

I will be (hopefully) upgrading to general in 2 weeks. I have already purchased an Icom IC-735, power supply and tuner. As a temporary measure for an antenna , I have a slinky dipole ( I know). I have several obstacles to overcome regarding an outside antenna to include, wife, neighborhood and dogs. I am still doing homework on the best outside solution.

My shack is on the second floor of my house above my garage. There is a walk in attic directly behind the desk where my rig sits. This attic is where I plan to install the antenna. It will be about 2 feet behind my rig spread out over 12' ,seperated by a sheetrock wall. My question is, am I in for trouble with RF etc? Do I need to be concerned with length of coax? should I just hold off until I am able to determine an outside solution?

thanks

[K0CMH]

That locatin would put you close to the radiating elements. You should check the RF exposure/limits tables to be sure there are no issues. These tables are in the ARRL study guide for the Tech license.

Your thought about RF problems in the shack is a distinct possibility. It sounds as if you will be level with the antenna and 12 feet away. This is pretty close. However, if it is cheap and easy to build and install, you may give it a try.

If you can locate the antenna above your shack, that could be possibly better.

My first concern would be the potential for harmful RF exposure being only 12 feet away. The most likely RF problems with equipment would be the rig getting shut off and the power supply being shut off.

Indoor antennas usually wind up getting RF into something in the house. If you have any of those "touch on/off" lamps, they almost always act up. Computer speakers are another big probability. Audio systems are another.

I have a 20 meter dipole in my second floor attic that will tune up and work on 40 meters. However, when running CW, it sometimes rings my electronic doorbell.

[G0GQK]

As suggested, not a good place for an antenna, unless... you only use low power. I understand your situation, many women are not inclined towards ham radio, or any other hobby if it takes your attention from their requirements. Is it possible to have a small vertical attached to the wall of your radio room which could be removed as required.? She will appreciate that the neighbours must never ever be inconvenienced by the sight of your antenna because you will be blamed even if the dog gets sick !

G0GQK

[G8CTJ]

I had a similar problem two months ago. I put up a long wire in the attic and it loades on all but top band. The problem was the earth trip would drop aout or if that stayed in the house alarm went off. I started to solve the problem by putting up a half wave 20metre dipole as high as possible along the ridge line inside the loft feeding it with a good quality balun and coax. Bingo 150watts and no effects on the alarm or earth trip and good radiation.
Against all theory I have sucessfully loaded this dipole on 40 metres and can get all around Europe on 40.
Have logged 20 countries in past 6 weeks with less than 2 hours per week operating time on 20 and 40.
Am now trying to get "her who must be obeyed" to agree to an outside beam on the roof. See my posting regarding how I physically do this in the DIY section.
Mike

[WB2WIK]

A "slinky dipole" is very much a monoband (single band) antenna, period. You could rearrange it every time you want to change bands, but that's an awful lot of work playing with the antenna and not operating. You really cannot set up a slinky dipole for, say, 40 meters and then hope to use it on other bands with a "tuner." Just doesn't work.

As such, other than for single-band temporary use, this is a poor choice.

Get something up, outside, high enough that nobody will notice it. If you have trees, this is easy. If you don't have trees, it's more of a challenge but can still be done with telescoping masts and stuff.

A good quality HF vertical can be a good solution, too. Outside!

WB2WIK/6

[WA7OET]

A roof mounted vertical is a good option, low profile and will work better than any attic antenna. If you are in a real pinch you could run the radials in the attic with only the radiator sticking up outside.

[K4UUG]

good morning,

I will be (hopefully) upgrading to general in 2 weeks. I have already purchased an Icom IC-735, power supply and tuner. As a temporary measure for an antenna , I have a slinky dipole ( I know). I have several obstacles to overcome regarding an outside antenna to include, wife, neighborhood and dogs. I am still doing homework on the best outside solution.

My shack is on the second floor of my house above my garage. There is a walk in attic directly behind the desk where my rig sits. This attic is where I plan to install the antenna. It will be about 2 feet behind my rig spread out over 12' ,seperated by a sheetrock wall. My question is, am I in for trouble with RF etc? Do I need to be concerned with length of coax? should I just hold off until I am able to determine an outside solution?

thanks

The Attic antenna is not a good idea because of the risk of exposure to RF energy because of the proximity to residents of the house, be sure to conduct an RF safety evaluation. ARRL says avoid using indoor and attic-mounted antennas if at all possible.

http://www.arrl.org/tis/info/rfexpose.html


http://n5xu.ece.utexas.edu/rfsafety/





I went with the Windom Dipole total length 135' 90' long leg 6:1 balum in center 45' short leg feed at balun with RG8U .It cant be seen from the road at all.Good Luck:)

[K0RGR]

Two feet separation is probably not a great idea - you will most likely experience RFI in the shack, if nowhere else. You're probably not in any danger at the power levels you're running, but you will violate the guidelines if you're over 50 watts on 10 meters.

Consider installing a phony roof vent to run your coax outside. If your house does not have rain gutters, you can run a dipole from the peak of the roof around the perimeter. Consider a trap dipole for coax-fed multiband operation.
Dipoles don't need to be sraight to work. My last one was 'Z' shaped to fit a tiny lot. Here's a 2-band half-sloper that should fit in from the end of your house to the back fence.

[KL7AJ]

good morning,

I will be (hopefully) upgrading to general in 2 weeks. I have already purchased an Icom IC-735, power supply and tuner. As a temporary measure for an antenna , I have a slinky dipole ( I know). I have several obstacles to overcome regarding an outside antenna to include, wife, neighborhood and dogs. I am still doing homework on the best outside solution.

My shack is on the second floor of my house above my garage. There is a walk in attic directly behind the desk where my rig sits. This attic is where I plan to install the antenna. It will be about 2 feet behind my rig spread out over 12' ,seperated by a sheetrock wall. My question is, am I in for trouble with RF etc? Do I need to be concerned with length of coax? should I just hold off until I am able to determine an outside solution?

thanks

If your dog objects to your outdoor antenna, I'd just tell him in no uncertain terms where his ALPO comes from.

End of story. :)

eric