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antenna project pdl-II made into a quagi please help antenna qurus!

Marconi

Usually if I can hear em' I can talk to em'.
Oct 23, 2005
7,081
2,087
343
Houston
Cool Irock ! I scraped putting the yagi elements in front of the pdl2 as i couldnt get even near a good match and the antenna wouldnt even near resonate where i wanted it to.I ended up putting a quad director in front of the pdl2 to see what it would do.I was able to get it to match and resonate but i think im going a different route.Im building a 4 element direct feed quad..Im using all fiberglass spreaders from the boom on out so there will be no extra added capacitance and i will be able to cut the wire exactly for the target freq.anyway , let me know how it goes for you and i will do the same , Darryl

sob, you could try tuning the driven elements for the pdl2 first without reflector/directors. When you got that close, then start adding the other quad elements, one at a time, and retuning as necessary.

I had a local buddy in the 80's that made a four element quad (not a quagi) using a PDL2 driven element setup and it worked very well. He tried to build it all at once by himself. He took over a year at the effort, but it would not work until he paid a local communications engineer with the Harris County Sheriff's office to set it up right. As far as I know the driven emement was not modified in any way different than the PDL2. This engineer rebuilt the beam just like I described above, get the driven element to tune, and then add the reflector first to tune, and then add the two directors, one at a time, tuning as he went.
 
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IRock817

Active Member
Oct 29, 2011
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The boom and reinforced hub and the metal hubs are here! The hubs are already at the desired locations. I've got a long list too make up for the replacement stainless hardware. There's a new moonraker in the box out in the garage to pilfer all the elements from. There's alot of cleaning to do. Plus the tower has to be setup.
Talked to the tech tonight and he said he wants to come down when I get everything ready and do the bulk of the assembly and tuning.
There's a ton of work to do, but I'm real excited to get it up in the air and start the shout outs.
This is gonna be an awsome antenna.
I'll get some pics along the way!!
 

IRock817

Active Member
Oct 29, 2011
168
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interesting thread,................ I have a hardly used PDL II and a slightly used MR 4,..... and a bigger and longer boom.

i plan to turn it into a PDL-6 later this year when I get back to West TN.**Jump_im**

I havne't done an ENZIC on it yet, but I think anything over 5 elements is gonna be "ego":whistle:

That will be a killer antenna! That's a lot of weight hanging out there unless your planning on some kind of gantry system. Take pics. And good luck.
 

IRock817

Active Member
Oct 29, 2011
168
31
38
Cool Irock ! I scraped putting the yagi elements in front of the pdl2 as i couldnt get even near a good match and the antenna wouldnt even near resonate where i wanted it to.I ended up putting a quad director in front of the pdl2 to see what it would do.I was able to get it to match and resonate but i think im going a different route.Im building a 4 element direct feed quad..Im using all fiberglass spreaders from the boom on out so there will be no extra added capacitance and i will be able to cut the wire exactly for the target freq.anyway , let me know how it goes for you and i will do the same , Darryl

Did you use the dimensions I sent you? I don't have a clue what yagi elements look like. but if they aren't exactly like the Avanti elements my schematics won't work!
 

sob

kc7max
Apr 1, 2012
15
2
13
sob, you could try tuning the driven elements for the pdl2 first without reflector/directors. When you got that close, then start adding the other quad elements, one at a time, and retuning as necessary.

I had a local buddy in the 80's that made a four element quad (not a quagi) using a PDL2 driven element setup and it worked very well. He tried to build it all at once by himself. He took over a year at the effort, but it would not work until he paid a local communications engineer with the Harris County Sheriff's office to set it up right. As far as I know the driven emement was not modified in any way different than the PDL2. This engineer rebuilt the beam just like I described above, get the driven element to tune, and then add the reflector first to tune, and then add the two directors, one at a time, tuning as he went.

thanks Marconi , that sounds like the way to do it.i did a bunch of searchs and determined after reading this http://www.eham.net/ehamforum/smf/index.php?action=printpage;topic=78287.0 i decided to do 1 0f two things.either uses the pdl2 with two quad director elements in front of it with ALL fiberglass spreaders and use the quad calculator to caluculate the lengths or just build an true quad antenna.In that read above they discuss how having partial conductive spreaders like the ones the moonraker and pdl2 uses on the reflector and what i was going to use on the directors causes capacitance and throws off what the measurment of the quad element should be for the desired freq. Irok , you might want to read this , Darryl (kc7max)
 

WA2SI

Member
Jun 6, 2011
66
3
18
Long Island, NY
Hey guys,

Just curious... Why take a PDL II, which is a polar diversity loop, i.e. a true quad, and turn it into a quagi, which is just crossed Yagis with a quad reflector? Isn't that a step back? A full quad will generally outperform a Yagi of the same size.

Vy 73 de Bert
WA2SI

Sent from my ADR6400L using Tapatalk 2
 

IRock817

Active Member
Oct 29, 2011
168
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38
no i diddnt , how did you send it?

I just sent it again! I wondered why I hadnt heard from you on this. Something I didn't put in the E-Mail was that we are using 14 gauge stranded guy wire from true value for the wires.
Take some pics of your build. It's nice to share!:whistle:

Let me know that you did in fact get the E-Mail if you would.
 

IRock817

Active Member
Oct 29, 2011
168
31
38
Hey guys,

Just curious... Why take a PDL II, which is a polar diversity loop, i.e. a true quad, and turn it into a quagi, which is just crossed Yagis with a quad reflector? Isn't that a step back? A full quad will generally outperform a Yagi of the same size.

Vy 73 de Bert
WA2SI

Sent from my ADR6400L using Tapatalk 2

We aren't really changing the PDL2! We are simply adding directors for forward gain, and tightening it up a tad!
The loop and gamma system is still set up per the original instructions.

Thanks
 

sob

kc7max
Apr 1, 2012
15
2
13
Hey guys,

Just curious... Why take a PDL II, which is a polar diversity loop, i.e. a true quad, and turn it into a quagi, which is just crossed Yagis with a quad reflector? Isn't that a step back? A full quad will generally outperform a Yagi of the same size.

Vy 73 de Bert
WA2SI

Sent from my ADR6400L using Tapatalk 2

from what i understand the only reason the quad out performs the yagi is the driven element of the quad has more gain, after that adding directors on either the quad or the yagi is a wash between them.back when, we made a quagi just because that was the parts i had.some people say by making a guagi you get the best of both antennas.Im not a pro , this is just what ive learned through reserch.and alot of people run them on uhf/vhf.the thing that throws everything off here is that the pdl2 is a quad that is driven by a folded dipole and thats way over my head!so the pdl2 isnt a true quad and is a dipole/quad antenna.
 

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