Antenna Project

[RickC.]

Got back to working on the antenna today and got the ground radials attached and the matching circuit hooked up and results were good .

Channel 1 1.4:1
Channel 20 1.3:1
Channel 40 1.2:1

Putting in about 22 watts.

Did not have to use the coax capacitor, actually results with it on were really poor. Tap point on the coil was typical, about 2 turns down. First contact was about 50 miles north of me with the feed point of the antenna about 6ft. off the ground .

Next job is to get it on the house and about 35ft. up.

More to come.

John

Hey John,

I'm coming to the party late on this one (you snuck this by me while I was tied up at Talladega), but good stuff! I was wondering what you were going to do with this that you needed an LC circuit at the base... But right, you shouldn't need a capacitor across this one. And your coil looks better than the one I made with the runny epoxy!

I look forward to seeing more pics and hearing how this performs when you have it up in the air.


Rick

 

[JDemoret]

Thanks Rick. So far the antenna has performed alot better than expected and I'm really excited about getting it up in the air.

Homer, I picked up 40 ft. of 1 1/4 inch EMT and I'm going to try to use it all, will let you know how it goes once I get a full day to work on it and some good weather.

John

 

[JDemoret]

Finally got the antenna up in the air. Had to settle for 32ft. at the feed point but that's alot better than 6ft. where's it's been for the last two weeks. Had to replace the bottom section as it snapped in the first attempt to get it up but was able to fix it and eventually got it all in place.

Final SWR:
Channel 1: 1.4:1
Channel 20: 1.2:1
Channel 40: 1.1:1

The antenna is reading "short" and I haven't messed with the tap point on the coil yet and am not sure if it would change anything and I need to double check the angles of the ground radials to make sure their at 45 deg. and again not sure if it would change anything but those are the only options I have unless I take it completly down and add more to the radiator. Oh well, it's all good.

John

 

[W5LZ]

About the antenna reading 'short'/shorted(?).
Depending on how that coil is connected, it should read as being shorted at DC. That doesn't mean it will be a 'short' at the frequency of use. I can't tell from the picture (and am too lazy to go back through the thread), but if the bottom of the coil is connected to ground on the SO-239, then it is a DC short, and is still not a problem at the frequency of use. If the bottom of that coil is connected to the SO-239's center pin, then it isn't a 'matching' coil, it's a 'loading' coil. If it shows a short this way, then there is a problem somewhere.
- 'Doc

 

[HomerBB]

Perhaps he's referring to the SWR being higher on 1 than forty which by some is said to be short and can be fixed by lengthening the vertical whip on an antenna. . .

BTW, it looks good.

 

[JDemoret]

Doc,
I'm sorry I was not clear. The antenna is showing physically short according to my SWR readings. I know that adding to the radiator would tune the antenna but I'm going to try messing with the tap point on the coil and the ground radial angles. Thanks for the come back.

John

 

[W5LZ]

Hmm. Guess I might pay a little more attention, you think?
- 'Doc

 

[JDemoret]

It's all good Doc!

John

 

[JDemoret]

Homer,
For some reason I missed your reply . Thanks for the compliment and yes that is what I meant. As of right now haven't been able to work with it any further but will fool around with things and let you know.

John

 

[HomerBB]

Homer,
For some reason I missed your reply . Thanks for the compliment and yes that is what I meant. As of right now haven't been able to work with it any further but will fool around with things and let you know.

John

Cool