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Post by spitfire441 on Aug 4, 2008 5:11:43 GMT -5
I have a PDL2 and I think it is a good antenna. Not great, but does what it does well for the size. It has about the same gain as a 3 element yagi. I like the switchable polarity. I am running mine in circular polarity now. It blows away my 5/8 GP for skywave propagation. But my 5/8 still out does it locally, under most conditions. For far out stations on groundwave it is a toss up. The PDL2 is at 25 feet and the 5/8 GP is at 45 feet.
Try the rejection test again with your friend, except don't put him in the back at 180 degrees. Put the other station in the "corners" either at 120 or 240 degress from front then see the rejection!
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Post by djrebel on Aug 9, 2008 8:59:25 GMT -5
no contest, any beams will out perform any vertical antenna...Dj
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Post by Sniper..Unit 305 on Aug 18, 2008 12:34:31 GMT -5
Well, through all my doubts and fears of wasted effort, I am actually surprized and impressed with the little PDL2 beam by Avanti. At this time, I am operating a Maco V5/8 ground plane at approximatley 60-65 ft to the base. I assembled a PDL2 and put it on a push up pole for testing. The SWR was a 1.4 on Channel 1 and 1.2 on Channel 23. I tested it with a number of operators in PA and NJ today and they all said that the PDL was louder and stronger signal and its only 25 feet or less in the air! I also checked it locally for rejection, and on the ground plane I was casting a S30 or more, and on the PDL with the back directley to him I was only casting a S9... Almost the same on my end. I could take him from a 35 to a 10. Not too bad. What is anyone elses opinion on the PDL2? Dr. Rigamortis, according to your first post you were doing better at 25' with the PDL than the 5/8. Have you any obstructions at the location where the 5/8 omni was and the PDL is now ? Could be possible that you may even be overshooting some of the locals, really strange. I would definitly like to see some suggestions posted to this problem since I too am curious as to why your receive and transmit would be down with the beam. Sniper ..OT2194 |
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Post by spitfire441 on Aug 18, 2008 14:04:29 GMT -5
I say antenna hight, my PDL is at 25 feet, my 5/8 GP at 50 feet, the GP does better 90% of the time groundwave, the PDL does better 90% skywave. Whats cool is when some one is FAR out, say 60-70 miles, the PDL usually wins. Also, the PDL on 10 meters, horizontal to horizontal is the sure winner everytime.
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Post by spitfire441 on Aug 19, 2008 4:43:44 GMT -5
Spitfire I just re-read your first post, and maybe I am seeing the same thing you are. Locally, its not a winner, but far out it is??? I was talking into IL last night to stations I have never heard before, and they were all saying that they broke me because I was so loud, they knew I had to be "more" local than 60-75 miles away? I may be over shooting the locals. I think the PDL has a low take off compared to the 5/8 GP. So maybe that is the deal. It does have pretty good rejection, but just like the graph shows on all the sales literature, it is WIDE in the front, and then closes in at the rear. Thanks for your info. From my seat of the pants labratory I would say you are seeing the same thing I am. I can't say "overshooting" locals is the explaination, but I ain't got a better one.The PDL-2 gots ears!. I can't quite explain it either. But hey, you are seeing the same results I am. Kinda weird. BTW, the driven element on the PDL-2 is one full wave. |
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Post by zman on Sept 24, 2008 16:42:03 GMT -5
The PDL is a great little beam. Around here they were (and still are) very popular with the CB ops that wanted a dual polarity beam but don't want a huge skyhook. I had one once and it worked pretty slick. I wish i could find one cheap just to have another to keep back for keeps.
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Post by Marc on Sept 26, 2008 2:18:02 GMT -5
One question did you set the gamamatches the way the instructions showed?
vert to lower right loop as you are faceing the front
and horz to the lower left.
If you placed the gamas on the upper loops you will be out of phase and that could cause a drop in both TX and Rx.
just a thought.
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Post by n9ydx64 on Sept 27, 2008 20:15:18 GMT -5
I think i have talk to you before when i live in illinois. What part of missouri are at. I am in north west tenn. now. about hour south of illinois.
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Post by zman on Oct 11, 2008 12:31:43 GMT -5
I have always wondered how a PDL would work if it was fed directly the elements extended on a longer boom, and the goofy gamma system was eliminated. I guess that will be my next antenna project.
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Post by Marc on Oct 15, 2008 9:54:05 GMT -5
The PDLII is not a true quad , more of a folded dipole.
That is why the gamma match. A true quad can be direct fed
with50 ohm coax ,but would use 6 to 10 raps of the feed-line on a 1 1/2 " form (PVC pipe), for RFI.
now the longer the boom the higher the input impedance at about 6 ft 6" you have 50 ohms.
at close to 7ft 9" it goes up to about 75ohm tricky to match with out a gamma or the likes (this is where I would try the PDLII).
Around 10ft 9"or so it is up to 120 ohm back to a range that a 75ohm match of about 6ft 9 in can handle and with wider bandwidth.
The spacing would be for any number of elements.
Unlike a Yagi the directors on a quad do not get shorter as you move away from the driven element, and the spacing does not increase.
Marc
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Post by spitfire441 on Oct 15, 2008 15:58:15 GMT -5
The PDLII is not a true quad , more of a folded dipole. That is why the gamma match. A true quad can be direct fed with50 ohm coax ,but would use 6 to 10 raps of the feed-line on a 1 1/2 " form (PVC pipe), for RFI. Marc What?  I am sorry but I respectfully diagree. A quad is a quad is a quad, meaning it has 4 equal sides. The gamma on a PDLII is there so you can feed it in the horizontal or vertical plane.If you feed it in the corner it is vertical, feed in the center, its horizontal. Cannot get dual polarity feed with out the gamma. Thats why it has a gamma. It is still a 2 element quad with dual polarity feed. |
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Post by Marc on Oct 15, 2008 17:11:54 GMT -5
If it was a true quad, the wires would be insulated from any spreaders supporting them and feed from the side or bottom, the orbital loop feeds the vertical or horizontal spreaders which feed the wires thus electrically it is a folded dipole driven wire element .
As far as needing the gamma to feed a single wire,look at the Signal Engineering quads no gamma one wire vertical or Horizontal. Does use a matching system but not a gamma
Yes Quad means four but four sides does make it a true Quad.
I am willing to call it a hybird quad for a better term.
Marc
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Post by bob85 on Oct 15, 2008 23:31:06 GMT -5
mark is right, the pdl is no ordinary quad, two of the spreaders on opposite corners are wholly conductive, heres the patent with full explanation of how its fed and how it works when setup correctly, patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=3&f=G&l=50&co1=AND&d=PALL&s1=3,475,756&OS=3,475,756&RS=3,475,756 |
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Post by Marc on Oct 16, 2008 0:39:14 GMT -5
Dr. Rigamortis The one with fiberglass is the reflector.And yes it is isolated from the driven element. But the wire on the driven element is not isolated from the front spreaders. The Driven elements(front) are all aluminum. They are isolated from the boom by the plastic hub.The center conductor of the coax feeds the lower vertical or left(from front) horizontal elements. the shield side feeds the two upper loops through the metal hub which feed the upper and right side elements. So there is no isolation between any part of the spreader elements, www.cbtricks.com/ant_manuals/ant_spec_avanti/pdl-2_av122.pdfPage 6 Items 1000 and 1001 are the driven elements. Marc |
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Sandbagger
Administrator/The Boss 
Posts: 6,247 
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Post by Sandbagger on Oct 16, 2008 7:41:31 GMT -5
The wires are insulated from the gamma. The elements are like those on a Moonraker reflector. Aluminum at the bottom, but the extenders are fiberglass. Thus insulating the wire. There isnt any direct link to the wire from the gamma. That's true only for the reflector. The driven elements are solid aluminum and the driven wire is fed from those. The PDL is actually more of a "Quagi", having characteristics of both the yagi and the quad. The reflector is quad, but the driven elements are a combination. |
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Post by spitfire441 on Oct 17, 2008 10:23:28 GMT -5
I will concied the point it is a hybrid or two dipoles feed in phase with a quad reflector.
If you look at the current distribution on the gamma and aluminum speaders on the driven element, it is nothing more than a way to feed the quad or phased dipoles or what ever you want to call it. It is still a full wave quad "radiating element" with the rest being a way to feed and support it. The reflector is a insulated from the boom quad.
If it looks like a quad, works like a quad, and walks like a duck and talks like a duck, I have no problem calling a PDL-II a 2 element quad. What ever the fine scientific breakdown may be.
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Post by Marc on Oct 18, 2008 9:52:48 GMT -5
Yes it is the equivalent of a full wave . But actually with the center conductor feeding the lower vert spreader and the shield feeding the top vert spreader (in vertical polarization) the current splits at the bottom tip of the element and flows up the sides it is actually two 1/2 waves in parallel electrically . that is where it gets the extra gain.
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Post by zman on Oct 18, 2008 20:23:30 GMT -5
Marc. I tried to load the patent info and it would not load. Is there another way to be able to see it?
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Post by Marc on Oct 18, 2008 20:50:17 GMT -5
It would not load for me either.
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Post by Marc on Oct 20, 2008 12:46:24 GMT -5
Go to this site www.freepatentsonline.com/Create a free account then search 3475756 you can read and print but cant copy and paset or download. |
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Post by bob85 on Oct 23, 2008 19:52:26 GMT -5
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Post by Marc on Oct 23, 2008 21:32:38 GMT -5
Thanks Bob we found a different site to lookat it from.
That paten is for the origanal PDL that did not have a gamma loop there is a pic on retrocom page 3 or 4 in old cb adds,
I am still looking for the one for the loop itself.
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I am sorry but I respectfully diagree. A quad is a quad is a quad, meaning it has 4 equal sides. The gamma on a PDLII is there so you can feed it in the horizontal or vertical plane.If you feed it in the corner it is vertical, feed in the center, its horizontal. Cannot get dual polarity feed with out the gamma. Thats why it has a gamma. It is still a 2 element quad with dual polarity feed.
