| Author |
Message |
    
super
| | Posted on Thursday, September 06, 2001 - 3:36 am: | 
|
does a dipole antenna have to be made out of 14ga standed wire or could you make a shorter one with 6 or 8ga soild copper instead of the 14ga stranded what im getting at is im living in a apartment for a while and want to make small- hidden-stealth antenna Ill be running around 500 watts with 213 coax i know 213 is to big for 500 watts but I got 100 feet of it for free and its brand new |
Tech181 (Tech181)
| | Posted on Thursday, September 06, 2001 - 12:30 pm: |
|
super,
You still have to make the antenna the correct length. Changing the thickness of the wire won't help.
Steve
Tech181
Tech181@copperelectronics.com |
707
| | Posted on Thursday, September 06, 2001 - 2:49 pm: |
|
super-
Here's what I run. Not great for local, works nicely for DX
http://www.dxring.net/srg.htm |
boobietrap
| | Posted on Saturday, September 08, 2001 - 7:54 am: |
|
Try twisted pair wire, it has a velosity factor of about 66 compaired to 95 for wire, which should make it about 1/3 shorter. I have never tryed it but in theory it should work. Of course start out long and trim until you get an acceptable swr. An antenna match box is another solution. I had a friend that claimed he used a couple of lawn chairs on the roof of his house , tuned them in and actually got out. (not recommended) |
Funtimebob
| | Posted on Wednesday, May 15, 2002 - 3:05 am: |
|
The standard formula is 468/freq(mhz) fot a half wave dipole. If the wire is insulated you will need to shorten the wire 3-5% because of capacitance effect of the insulation. the formula is the same reguardless of the wire gage. you can use this formula for base reference and then do a little pruning. also dont forget to get yourself a 1:1 balun. |
Marconi
| | Posted on Wednesday, May 15, 2002 - 8:39 am: |
|
Super, the guys are right, you won't save a lot by using the large wire. If you cut it right and leave enough on the ends to wrap it back on itself you can make it tunable. For you temp setup, you don't need to make the ends fixed. Use some decent insulators and go to work.
You will find, allowing for the wattage of course, that the lighter everything is in your case, the better. You probably will not need a balun as you should be able to make a good natural match. If you lay the wire flat you will notice a broadside horizontal response with possible nulls at the ends of the wire. Of course a balun will improve this arrangement if you want to go to the expense, but I doubt you could really tell any differences.
If you make it an inverted V, 100-140 degrees of angle at the feed point, you will make it a bit more omni-directional and somewhat vertical. This will also show you a bit more bandwidth.
If you make it a straight sloper it will also tend to make it a bit more vertical with some directional qualities that are often hard to determine. Try to put it to an outside wall that has little or no plumbing or wiring in it and you should do fine, if you don't have metal in the wall.
You will probably be able to work skip a bit better than local traffic. If you can get it hanging outside somewhere, in the open, and about 30-40 feet high, it will help considerably.
You will not need to make an earth ground with this one. Try to keep the loops at the ends a little loose (large) if possible. This cuts down on capacitance at the high current points in the antenna. If you go inside, also remember that the ends will be hot with RF and can make a nasty burn if touched.
Marconi |
Funtimebob
| | Posted on Thursday, May 16, 2002 - 5:14 am: |
|
There would only be what? a extra $3.00 tacked onto the overall expence if you made a simple balun yourself out of a piece of coax.
I could be wrong i'd have to check my books but if I remember correctly couldn't you make a simple 1:1 balun by cutting some coax into a 1/4 wavelength loop and attaching the ends in the proper mannor or was that for a 4:1 balun? |
|
