PDL2 & Moonraker hybrid for 10m

[warrior369]

Leafin' thru some old e-mags and came across this: see attachment.

 

[2RT307]

I've seen pics of these antennas over the years, but never saw any dimensions on how to do it. Thanks for posting it up!

73,
RT307

 

[Captain Kilowatt]

I remember when that article was printed. In fact I ripped it out and saved it.

 

[w9cll]

Sweet I wish I would have seen this years ago when I had my PDL2

 

[2RT307]

I still have a PDL II in storage. Fascinating antenna to me... they sure seem to pack a whallop of a signal from such a small footprint. The modified antenna with 4 elements and dual polarity on that short of a boom is interesting to me.

73,
RT307

 

[WA8ZYT]

What is the purpose of the egg beater thingees on the Moonraker? Some kind of matching device?

 

[Road Squawker]

I still have a PDL II in storage. Fascinating antenna to me... they sure seem to pack a whallop of a signal from such a small footprint. The modified antenna with 4 elements and dual polarity on that short of a boom is interesting to me.

73,
RT307

I also have a PDL-II and a MR -4 in storage.

I think I will construct something similar to this,....... but,.....


I don't understand why he cut 36 inches off the MR boom,... if I am constructing a PDL-IIII, I wouldn't cut the boom at all. I would just move DIR 1 and DIR 2 back 36 inches from the end of the boom and let the boom stick out in front of DIR 2 by 36 inches.

it may look" a little odd, but, ..... I may want the entire 186 inch boom again for another project.

also, if a wooden dowel is used to join the PDL boom and the MR boom, there won't be a very good metal to metal connection between them.
the MR boom and elements will be at DC ground, but, the PDL boom and reflector may not be. I would add metal straps across the joint of the two booms to ensure a proper metal to metal connection.

actually, as I think about it, why not use the PDL-II reflector and radiator, and use 3 (instead of just 2) of the MR elements as directors, making it a PDL-V (five)?

that would make the boom 241 inches long.

REF to RAD..55"
RAD to DIR1..56"
DIR1 to DIR2 65"
DIR2 to DIR3 65"

wire lengths for the elements
REF.... 110.5"
RAD....109.25"

D1.......195" tip to tip
D2.......192.5" tip to tip
D3... ...190" tip to tip

anyone see any major errors in my dimensions?

 

[AudioShockwav]

What is the purpose of the egg beater thingees on the Moonraker? Some kind of matching device?

Yes it is a matching device, Avanti used this orbital gamma match on the PDL II of years ago.



73
Jeff

 

[Shockwave]

The special insulating plastic hub used on the PDL driven element will not fit over the boom of a Moonraker and is why the booms are joined. There is also not enough material inside the plastic hub to drill it out and fit it on the boom while still maintaining enough clearance to prevent arcing to the boom. These antennas look good but I'm fairly confident improvements could be made by optimizing the element spacing. The PDL used wide spacing on it's 2 elements and I'm thinking in a 4 element model the front two directors should be wider apart than the reflector and driven to optimize gain on this longer boom. Some modeling would reveal the facts here.