Ideas on a 440 MHz antenna

[Turbo T]

I'm going to be installing a 440 MHz radio to my ham station in a few days and was thinking of making my own vertical. This will be in my home.

I'm thinking of using an old satellite dish and putting a 6 3/4" tall piece of copper wire in the center, with an insulator....I'm thinking this outta work for a 1/4 wave antenna....what do you think?

If not that, then maybe a 13X13 piece of flat sheet metal with the piece of copper wire?

One question I have wondered, is how much of a difference will it make in "getting out" with the 440 MHz antenna inside the home as opposed to the outside? As I understand, 440 MHz can pass thru walls...?

 

[W5LZ]

That dish isn't going to much good. Using three or four radials the same length as the vertical part would work just as well. With any UHF antenna more height would be of benefit. Height equates to range to a very rough degree. So would being outside rather than inside. Sure, RF passes through walls but there's always some attenuation when it does so. Keeping that attenuation as small as possible is good.
All 1/4 wave antennas are unity gain, meaning there is no gain to them. Most 'gain' antennas are vertical arrays, more than one 'section' separated by phasing lines/networks. Usually that's all enclosed in a fiberglass 'case' of some kind.
Lots of options.
- 'Doc

 

[Turbo T]

Doc, just curious why would the dish not do as good?

 

[W5LZ]

To tell you the truth, it's more a matter of what practical problems it would present than electrical ones. They tend to be awkward, more noticeable, catch more wind, and who knows what. They are also made for receiving, so just how 'robust' is the reflecting material? I really doubt if typical transmit power at UHF would burn it up, but can you be sure of making adequate contact to it? Beats me, I don't know. Just happen to have one and want to try it? Do it.
- 'Doc

 

[Moleculo]

If you just want to make a 1/4 wave vertical, make one out of a SO-239 like this:

It's so cheap and easy a caveman can do it

Camden County Amateur Radio Society (Georgia) - CCARS INC.

 

[Turbo T]

Thanks for the link, very useful.

One thing though, is I've considered trying to mount this 440 antenna to the side of a pole that currently holds my 2 meter Ringo Ranger.

The pole is metal, wondering how far away from the metal pole do i need to place the 440 antenna so it doesn't have SWR issues?

Thanks.

 

[W5LZ]

Turbo T,
I'm surprised someone hasn't replied.
The quick-n-dirty answer is to mount it as far as is practical/possible from the tower/pole. Then you 'deal' with the SWR problems if any, just like you would any antenna. I would think that putting the thing on the side of the tower/pole that most of your common contacts are on would be a good idea. That tower/pole will affect the radiation pattern to some extent too. (A metal mounting structure makes for a terrible 'director', but can make for a useful 'reflector'. Use that property if you can.)
Everyone has to 'deal' with possible SWR and directionality problems in this sort of situation (whether it's apparent or not), it's not a huge big deal. It comes with the territory, you know?
- 'Doc

 

[Turbo T]

UPDATE

I wanted to say again thanks for the link. I actually made 2 of the 440 antennas, the 2nd one worked great and still does.

I'm curious as to if it's possible for me to build my own dual band antenna that will do 2 meter and 70 cm? Or would i be better off just building a 3rd for 2 meter use only?

I'm not a big fan of having a bunch of antennas on the house or outdoors.

Also it mentions using a duplexer....presuming this is for when you run a dual bander?

 

[depark]

I wanted to say again thanks for the link. I actually made 2 of the 440 antennas, the 2nd one worked great and still does.

I'm curious as to if it's possible for me to build my own dual band antenna that will do 2 meter and 70 cm? Or would i be better off just building a 3rd for 2 meter use only?

I'm not a big fan of having a bunch of antennas on the house or outdoors.

Also it mentions using a duplexer....presuming this is for when you run a dual bander?

I made one of these aluminum j-pole's about 2 years ago and it works great. I get excillent signal reports and also awesome distance. The whole build cost me about $25. Here bis the link. J Pole Antenna. Have fun building it, you won't regret it!!