One-Radial Ground Plane vs Dipole

[Skynet 15]

Hey everyone, well here's my new radial and mount setup.cleaned up the pole to look a little more "professional". Aside from that, now im getting more power out per say, BUT... My SWR is now at almost 2.5 on 40 and 1.8-2.0 on 1 am I just being dumb, by not bending the radials to a 33-45 degree angle or is it as simple as tuning the tip? Jeez. Thanks in advance guys.

 

[Skynet 15]

ALSO! Forgot to state this all homebrew, all...

 

[The DB]

Have you tried tuning the tip? I would look at that first.

Is the vertical element one of those so called "mobile 5/8" that you talked about earlier in this thread?


The DB

 

[Skynet 15]

Have you tried tuning the tip? I would look at that first.

Is the vertical element one of those so called "mobile 5/8" that you talked about earlier in this thread?


The DB

Maybe. Lol! Yes it is a 5' 5/8 wave.

 

[Skynet 15]

Maybe. Lol! Yes it is a 5' 5/8 wave.

I know its not the best possible choice by all means, but it's an experiment and learning process for me and fun. Working with what I have for now.

 

[vkrules]

tune the tip ,looking at your figures it's a little long

 

[vkrules]

never mind what some of the cb shops try to tell you. a 5ft loaded whip can never be a 5/8 no matter how much wire is on it.

 

[222DBFL]

You might be better of with a 102" or even an 108" whip. Just saying.

 

[222DBFL]

For the main radial in place of the so called 5/8 wave firestick. Just some food for thought and I'm sure you can find one for cheap if you look around. JMHO.

 

[Skynet 15]

Thanks for all the reply's everyone, so much help to me. I will down the road maybe even today try a 102-108 inch whip as my main radiator. But today I will be tinkering with it as far as tuning today... Now any thoughts on bending any of the radials or do they look good at the angles shown?

 

[The DB]

Maybe. Lol! Yes it is a 5' 5/8 wave.

Well, once I saw this answer I was going to tell you this...

never mind what some of the cb shops try to tell you. a 5ft loaded whip can never be a 5/8 no matter how much wire is on it.

Its not just CB shops, it is manufacturers as well. Electrically your antenna is nothing more than a shortened 1/4 wavelength antenna. Just because they use a physical 5/8 wavelength of wire means nothing, once they start coiling it up it is no longer electrically 5/8 wavelengths long. Further, the benefits from a 5/8 wavelength over other antennas isn't due to the fact that it is physically or electrically 5/8 wavelengths long, but due to the current node being higher. In the case of these antennas, the current node is at the exact same point as any other mobile antenna. The current node is the part of the antenna that radiates the most.

Essentially, the 5/8 wavelength claim is all marketing. And marketing is only about getting you to buy their stuff, not inform you of the truth about what you are buying.


The DB

 

[tba02]

My SWR is now at almost 2.5 on 40 and 1.8-2.0 on 1 am I just being dumb, by not bending the radials to a 33-45 degree angle or is it as simple as tuning the tip?

If you have the radials at 90 degrees, your impedance is ~30 ohms. If you angle them down to 45 degrees (+/-) your impedance will change to ~50 ohms which will improve your matching and lower your SWR. I would do that first. I doubt your will get acceptable SWR numbers by just using the tuning tip. This would also apply to the 102-108" whip.

 

[tba02]

Here's an example of how it changes just by changing the Load Impedance (Zl)
22 ohms/2.25:1 (using an average of your posted number)


45 ohms (because 50 would show a perfect match, but that is not the point of this example) - which is what changes when you angle the radials.



http://www.cdt21.com/resources/TechnicalTools/vswr1_01.asp

 

[Mudduckmobile]

yes, please make radials down to about 45 ` this will be a big help, and make tunning easer.
You really should come up with a 102 whip, and a spring or nut/bolt combo to combo. so you can tune the 102 whip with ease. (your nut / bolt combo is made up of 1in. long bolts and 1in. long threaded bits) you can add bits to make the whip longer as needed up to 108 long. Good luck and have fun!!!!

 

[Skynet 15]

Thanks for al the input everyone, I will try a large whip later on but will be bending the radials today. Maybe do some other tinkering too. I'll be posting the new swr readings later on. Thanks again for all your help and advice.