1 wire dual polarized quad

[johnny9]

ok just wrapped 5 turns around a 4 inch plastic piece..excuse my temp mud duck tape job. wind is bad today so needed it to stay temp only for now,does this look correct//

swr were 3.0 before
and 3.0--3.2 now with the choke wrapped out of my 75ohm transformer near the element..
ok wait..i DID NOT wrap the other horz one yet,,jujst the vert side.
this should be done first i think since the full wave wire is a split wire design i assume and wont read properly till i do the horz side also.

will be right back after doing that..

 

[johnny9]

wrapped the horz choke the same way for test purposes.
swr is now def came down on vert since doing both chokes.
with precise cut 75 ohm matching stub,for ch40 w/ 5 wrap choke ch1= 1.4 swr
ch40=1.7 swr (its built for ch 40 so maybe
element
wire is a too long,or short a
fraction?? )
i can live with this for now
horz ch 1= 3.5 swr
ch 40=2.4 swr

the 130ft run of coax from the shack may be 10 ft shorter on the horz coax than the vert coax..i wonder if that can make a diffrence. on horz swr.
or possible since i had to cut connectors of original horz quad 75 ohm stub it is a little short..i have another one i can make up,maybe i should do this now..
either way it can get used now or for another quad build
thanks for hanging in here with me and my antenna ignorance too!

learned a lot past week

 

[johnny9]

incase this may help another antenna ignorant person someday; i just checked swr 10 minutes after last post and horz went down to 2.4 on ch 1
and 1.8 on ch 40??????????? i asked my ham neighbor how?
he said the sheild was prob messed up or changed on that section..this seems true since that wire is a little shorter since cutting off original connectors possibly.
gonna remove section and check it out now..

 

[camaro1]

you want your turns on your choke form to be nice and tight, no gaps, yours looks a bit loose in the pic

 

[johnny9]

you want your turns on your choke form to be nice and tight, no gaps, yours looks a bit loose in the pic

yes that one is,thak you.
had a problem and fixed it with fresh solder on the horz center conductor where feedpoint was..both transformers are exact in length,re checked before wrapping other choke"NICE AND TIGHT I MIGHT ADD on this one..
now with both chokes temp installed swr readings are;
vert ch40= 1.7 horz ch40 = 1.8
vert ch1 = 1.4 horz ch1 = 2.4

i can handle this for now since i talk on 27.355 thru 27.555 mainly.

so the chokes were a big help,,thanks for making me understand better ,evevryone

what baffles me is my flat swr spots are;
horz is flat swr at 28.005mhz vert is 2.3

vert is flat swr on 26.405 mhz horz is 2.0

now i need to learn how to move those sweet spots where the swr are flat to ch 40 on vert and horz would be nice..
im still willing to tinker with it since i have 2 other antennas i can use in between fixes..
but if i cant get the swr better than they are maybe 2 separate quads will be better for me in the long run.
i can get the swr close to flat on them seperatly

i will say this,,i see no diffrence in the single wire horz side as a single quad by itself, and the new split wire horz side design im using now,except that the vert side i added def kicks the 70,s astro planes butt when built in with that "split wire"

 

[vkrules]

Glad your making progress. See if you can get the chokes closer to the feedpoint. In particular get the choke on the horizontal feed closer and see what it does to the VERTICAL swr.If I'm right it will move the flat spot up from 26 mhz. Also can you make the coax runs the same length . The different lengths maybe hiding whats really going on. Congratulation on what you have done so far.

 

[johnny9]

Glad your making progress. See if you can get the chokes closer to the feedpoint. In particular get the choke on the horizontal feed closer and see what it does to the VERTICAL swr.If I'm right it will move the flat spot up from 26 mhz. Also can you make the coax runs the same length . The different lengths maybe hiding whats really going on. Congratulation on what you have done so far.

THANK YOU. i sure dont like all the extra weight on my spreader tips..and the beefy coax makes it hard to get closer to the feedpoint, the horz choke is closer than the crappy first try in the pic as i could get it comfortably..
i feel i will be steering away from this soon to be honest.because of the weight on the tips and the big ugly balun looking thing lol..
dont get me wrong i will stand it up and check it in the am for a few hrs when dx is going on 38lsb..
i actually feel with the best swr i have gotton it would have been easyer to use a antenna tuner and not have all the weight on the arms,as the swr didnt change drastically like i was hoping i guess.
then again i am a beginner at this stuff.dont really no the best answer..
i will prob try the horz and vert together on the same coax like my neighbor has done.basically the horz quad in diamond shape fed at bottom and turn it to a sqaure so its fed on the corner..his works great and he loves it..
i like having the matching stub running straight down the spreader arms and nearly invisable way more than i thought i would..

on a side note,a round quad will be built in the next few months

 

[vkrules]

I was just going by the pic posted.If it was just the swr then a tuner would make you feel warm and fuzzy for sure.

 

[wavrider]

GOOD work
glad you got it going.

so lets break this down in easy terms.

basically you have an 3/4 wl piece of wire which is the same impedance as a 1/4 w/l wire.

So you have a 1/4 wl and a 3/4 wl, this is the same as a half wave dipole per say except you have a 3/4 wl instead of a 1/4 wl.

since both wires are the same length for both vertical and horizontal it has to be in your 75 ohm phasing lines.

you may have to experiment with different lengths of 75 ohm coax to get you "sweet spots" where you like them at.

OR a simple 2:1 balun at each feed point should cure the problem

http://www.packetradio.com/catalog/...ucts_id=2472&zenid=9t922e4jdg2doi1u1bsakg8ve6

or instead of an ugly choke with all the loops
you can use ferrite beads around the outside of your coax, alot less weight

http://www.kf7p.com/KF7P/Ferrite_chokes.html

 

[wavrider]

You have the dual quad working.

Now it is time to tweak it, you may experiment with moving the driven element a further distance away from the reflector, this will also change the impedance of the antenna at the feed point.

this may be the simplest and easiest way of lowering your input impedance instead of experimenting with the 75 ohm coax.

if you change the spacing and your quad becomes lower in vswr then please share the spacing distance that worked best for you.

Good luck and have fun

 

[johnny9]

its kinda a erie feeling having a swr more than 1.3 or so for me..but thats just what im used to in all the radios,mobile,and base ive had .
i run a rci 2995dx 4 yrs old and have no clue what a high swr would tear up..but when im talking on this new vert and horz on ch 38lsb the swr never goes over 1.5-1.7..on my cn-801 diawa meter,so id think i would be ok..well,i will go play with the antenna tomorrow after getting TAXES done ..that should be fun!

 

[johnny9]

Now it is time to tweak it, you may experiment with moving the driven element a further distance away from the reflector, this will also change the impedance of the antenna at the feed point.

this may be the simplest and easiest way of lowering your input impedance instead of experimenting with the 75 ohm coax.

if you change the spacing and your quad becomes lower in vswr then please share the spacing distance that worked best for you.

Good luck and have fun[/QUOTE]
thanks wavrider.. i did change the spaceing in the begining on the first thing i tried,,the 2 seperate wires 3 inches apart,,and moved the reflector up to 79 inches total spread"19 inches further away" and seen no diffrence..
i will try this in the am on this set up and re check swr and report back for sure..i wont change the length of the 75 ohm tranformer because as they are they are the exact length for 2 driven elements on a quad for ch40..i cant get any more for a while so have to skimp and save what i have for any other crash test dummy antennas

 

[HomerBB]

Johnny, is the rod your choke is taped against fiberglass or metal?
Also, I regret I wasn't clear enough for you with my post. I never meant to imply using more than one transformer. I never have on a quad.
How long in inches is the driven element(s) total of your antenna? You've never said in the thread, or else I can't find it.

 

[johnny9]

hey Homer the fiberglass rods are three eighths thick, 3 foot long, with 4 to 6 inches inside the aluminum tube, my reflector and everything is built for channel 40, the reflector is 37 foot 7 inch the driven is 36 foot 8 inch the element spacing is 5 foot 4 inches, I have moved the spacing up to 19 inches wider and then ended up coming back to this spot because there was no difference.the 30 6 foot 8 inch element I left on there when I cut the other side to make the horizontal and vertical,
if it weren't for the choke being so big and heavy I would redo all the wires and and make sure they are precise but I'm pretty sure they kind of have to be precise other than maybe a quarter of an inch. Seems to me I may as well try what the neighbor has been using for a month now and that's the horizontal and vertical together on the same beam same wire one coax,John

 

[johnny9]

remember this is a split wire design not two wires

hey Homer the fiberglass rods are three eighths thick, 3 foot long, with 4 to 6 inches inside the aluminum tube, my reflector and everything is built for channel 40, the reflector is 37 foot 7 inch the driven is 36 foot 8 inch the element spacing is 5 foot 4 inches, I have moved the spacing up to 19 inches wider and then ended up coming back to this spot because there was no difference.the 30 6 foot 8 inch element I left on there when I cut the other side to make the horizontal and vertical,
if it weren't for the choke being so big and heavy I would redo all the wires and and make sure they are precise but I'm pretty sure they kind of have to be precise other than maybe a quarter of an inch. Seems to me I may as well try what the neighbor has been using for a month now and that's the horizontal and vertical together on the same beam same wire one coax,John