Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

antenna project

C

Chatter

Member
Oct 28, 2009
33
0
16
chambersburg pa
i know this should probably be in the cb area but i figure hams might know a little more about this, no offence to you cbers out there. i still havent received my call sign yet and im iching to get started on a project, so ive decided to construct a 4 element quad antenna for my cb tuned for ch.19 (27.185)MHz, which has a full wavelength of 36.2056 feet. ive looked at some diy's on the net and i dont fully understand what im looking at. i know it sounds bad but im 31yrs of age with an 8th grade education, however im willing to work hard at understanding this stuff. all i need is the right guidance and the right tools/resorces. the diy's ive looked at seem targeted twards people who have an extensive knowledge about antennas. is there any sites out there for beginers or like quad antennas for dummies w/8th grade educations or something? Driven element??? Reflector element??? Directors??? please help!!! i want to know this stuff
 
Last edited:

If you follow all of the links on this page, you will spend days reading. http://en.wikipedia.org/wiki/Antenna_(electronics)

The driven element is the one which is connected to the feed line and is reasonant on the desired frequency. Director elements are placed in front of the driven element and not conected to any feed line. They are slightly shorter than the driver and get shorter the more and farther they are placed from the driver. Reflectors are not conected to anything either, and are placed behind the driven element. They are slightly longer than the driver and reflect any stray waves which make it past the directors and driver back to the driver.
 
Check out this web page for building quads:

Quad Antenna JavaScript Calculator for CB and Amateur Radio Communications

It has a calculator where you punch in the frequency you want it for and it gives you all of the dimensions you need. Punch in 27.185 if you want it for CB. You only really need 2 elements (the Reflector and Driven) but if you want more gain you can add the Director elements. From that web page, use the picture and instructions for the single quad picture on the top.

Here is another good instructional page. This one is for VHF, but you just adjust the dimensions to match what the calculator page says. Pay particular attention to the close-up drawings of how to feed the quad:

http://www.iw5edi.com/ham-radio/files/WA6TEY_4X-QUAD.pdf

You don't have to build the balun yourself if you don't want to...you can buy a 1:1 current balun pretty cheap to accomplish the same thing.

Actually, if you just build the 2 meter one instead of the CB one, you'll have something ready to use when your call becomes active. :) :)
 
When I built my quad I found this page very usefull...

The Ultimate Guide to 11 Meter CB Antennas

To be honest Chatter building an antenna like this is not very hard to do. The main thing is to follow the measurements as accurately as you can, and the antenna should be working very close to where you want it to. Double check your measurements and make 100% sure they are correct and I can't see you having many problems. The hardest part of making a quad is the spider part, the piece that holds the spreader arms to the boom, there are lots of different ways to do this but all you need to do is have a think about what would be the easyest way for you to do it, that will work and be strong enough. The link I posted suggests using hubs from a moonraker 4, which is an expensive way to do it unless you happen to already have a broken moonraker 4.

Lots of good advice given already and plenty of reading for you to do, but if you have any more questions the guys here will help you out I'm sure.

This is my 3 element quad for 27MHz that I finished a couple of weeks ago...

Image076.jpg
 
Quads have to be of a full wave length unless you want to do a -lot- of work making them smaller. That 'smallness' isn't going to be -that- small anyway, so isn't going to be worth the trouble in most cases.
The size of an antenna can typically be made smaller to some degree, but directional/quad antennas are also typically not a candidate for that sort of thing. One of the things that you 'give up' along with 'size' is the gain realized from that directional antenna, and usable bandwidth.
If size is that much of a problem, there are other types of antennas that should work for you.
- 'Doc
 
Chatter said:
do quad antennas have to be a full wave? can you use 5/8 or even 1/2 wave measurements to cut down on over all size?
Click to expand...

answer. No quads don't have to be a full wave, but you lose ALL of the benifits of a quad has to offer. so if your gonna make it less than a full wave, you might as well stick to a yagi.
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back