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Antenna height for beam?

I think you are going to have a kick-butt station if you follow thru correctly.
You sure have all the raw materials in place.

I would also add that it would also need three 8 ft ground rods planted next to the base and bonded with the appropriate cable to the mast. For your Oklahoma lightning moment - or ten.
 
It turned out the M-4 and PDL-2 had been out in the weather way too long.

Searching again...

Thanks for all the replies.
 
If your going with a different tower anyway I recomend a maco m105 h/v,. Have mine at 58 ft to the boom and it works great. With good groundwave conditions to another beam ive talked 170 miles vertical and over 200 horz groundwave with some juice. 60 miles would not be a problem anytime dx wasnt running with a fuzz extra in the wire. DX is a blast.
 
AudioShockwav said:
I used to run a PDL-II on a 30 foot free standing tower, and it was a very good set up. Light weight, used a small rotor to turn it and dual polarity all in a small package.
Even at 30 feet it worked very well.....it replaced a 3 el that i was using on the flat side, and it worked just as well.....with the added benefit of being able to switch from vert to horz with the flip of a switch.
I still wonder why no one picked that design up and continued to build the PDL-II, it was a great antenna.

73
Jeff
Click to expand...

I also had a PDL-II 20 years ago and just purchased another one in new condition to be installed soon. You are absolutely correct in saying it works just as good as a 3 element yagi with dual polarity. I've been trying for years to convince various antenna manufacturers I deal with to bring some variation of the PDL-II driven element back to market. Be it the same two element quad or a larger Quagi hybrid.

It looks like my wish is coming true finally. I wrote Tom at Maco concerning the possibility of bringing something similar to the PDL-II back. He recently wrote me back saying he obtained an original PDL-II and had it in his shop for investigation and adaptation. Indicating that there were plans to put some variation of it back into production. I can hardly wait to see what direction he takes it in.
 
hotrod said:
im not up and up with beams but isnt the maco y quad =same as the pdl2
and the maco shooting star same as the moonraker 4
Click to expand...

The boom is 1' longer on the maco as opposed to the avanti moonraker.

If I were offered one or the other I would step on your mother's neck to get at the moonraker.
 
The Y quad is a far cry from the PDL-ll. In the case of the Y quad you have a simple 1/2 wave yagi driven element that in itself has 0 db gain. The PDL-II driven element is a full wave element driven by a 1/2 wave element! That makes the PDL-II perform like a 3 element yagi on a short 58 inch boom.

I understand Moonrakers are sought after antennas by Avanti. Having owned both the Moonraker IV and the Shooting Star, I'd like the Moonraker to sell it and the Shooting Star to use it. The shorter boom on the Moonraker IV reduces forward gain and places the driven element close enough to the support mast to cause complications in tuning the vertical side.
 
Antenna Height for a Beam?

For CB first consider FCC Rules Part 95.

§ 95.408 (CB Rule 8) How high may I put my antenna?
(a) Antenna means the radiating system (for transmitting, receiving or both) and the structure holding it up (tower, pole or mast). It also means everything else attached to the radiating
system and the structure.
(b) If your antenna is mounted on a hand-held portable unit, none of the following limitations apply.
(c) If your antenna is installed at a fixed location, it (whether receiving, transmitting or both) must comply with either one of the following:
(1) The highest point must not be more than 6.10 meters (20 feet) higher than the highest point of the building or tree on which it is mounted; or
(2) The highest point must not be more than 18.3 meters (60 feet) above the ground.
(d) If your CB station is located near an airport, and if your antenna structure is more than 6.1 meters (20 feet) high, you may have to obey additional restrictions. The highest point of your
antenna must not exceed one meter above the airport elevation for every hundred meters of distance from the nearest point of the nearest airport runway. Differences in ground elevation
between your antenna and the airport runway may complicate this formula. If your CB station is near an airport, you may contact the nearest FCC field office for a worksheet to help
you figure the maximum allowable height of your antenna. Consult part 17 of the FCC’s Rules for more information.

WARNING: Installation and removal of CB station antennas near powerlines is dangerous. For your safety, follow the installation directions included with your antenna.
 
There is no "best" height above ground for any antenna. There are some fairly good rules of thumb though, but they are only that, approximations.
On the average, something like a wave length above ground is nice. The only reason for that is that's where the dirt 'ground' stops playing a large part in the input impedance of the antenna, and where any directionality from non-multi-element antennas starts to really get 'directional'.
To some unknown degree, more higher tends to be more better. That "unknown degree" thingy is dependent on the antenna's environment, what's around it, etc. That's different for all installations so is unpredictable to a large extent.
'Best height' is whatever height you can manage. Less than one wave length? That'll work just fine (and has for a lot of people) too. You may be 'giving up' something, but unless you are lowering that antenna to only one wave length above ground, how would you ever know? Add in that "Momma Nature' has the final hand in what you hear because of 'her' propagation, and it's a chance either way. And because there's nothing "set in stone" about that one wave length height, a few feet either way just won't make a 'world' of difference either way. Agonizing over a couple of feet is silly!
- 'Doc
 
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PDL2x4.JPG

Shockwave, your boy better hurry! The PDL4 has been in service for years! It's a PDL2 and a MR4 combined at around 14 DB. I have one in my utility trailer that I received from the builder last week. It'll be reaching out and touching you in a few weeks!

Okie, unless your stacking beams, you don't have to go crazy with concreting base sections, adding multiple guy lines or the such. The wind here in Oklahoma is a little trying but your probably not gonna go higher then 60 foot to the tip. The damn lightning and freezing rain is what I worry about here. If you end up with a beam put the boom at at least 36' and it'll work very well. As stated height is might though! (y)

Okie can you still get a handle on the PDL? We have a machinist that's making the non-conductive hubs and I'd like to put together another one!

Thanks

Everyone have a good Independence Day!!

Driftwood
 
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Height plays a big part in what you hope to achieve, especially if we are talking about trying to work the other side of the World on a regular basis, or content with a maximum of a couple of thousand miles, the arrival angle for signals from different parts of the World should be in your consideration when planning an antenna installation. This is one of the main benefits when stacking antennas, one chap I speak to regularly in Australia has a 200' tower with four stacked five element mono band yagis, granted this isn't for CB, but the same rules apply, he is consistently stronger on his top antenna, by some 20 - 30db, than he is on his lower antenna at 60', that is all down to the lower arrival angle of his signal being near horizontal, I can talk to him long after propagation to his part of Australia has all but died out.
What causes this lower angle is the effect ground has on the take of angle, his lower antenna having a higher take off angle than his upper antenna. If all the OP wants to do is work a friend 60 miles away, then I'd want to make sure your friends antenna is in the same plane, ie horizontal or vertical, it would be a waste of effort mounting a yagi flat side if your friend only has a vertical antenna, with around 26dB of cross polarisation loss, you'd be worse off than you are now.

HTH;)
 
This is a tricky question unless you're talking line of sight. Then the answer is easy. The higher the better. Not so much the case for DX work. As was mentioned, one wavelength is good but tends to favor short hop skip out to around 1500 miles on this band.

Going higher will lower the angle of radiation but it also breaks the main lobe up and places more nulls in the pattern. For example many Yagi's will produce a TOA of about 14 degrees at one wavelength. That is good for lots of DX. At two wavelengths you now have a deep null right at that 14 degree TOA but you have a nice peak just above and below the 14 degree null.

Where we had the strongest signal targeted at 14 degrees, we now find the weakest signal their due to that deep null. Years ago a friend donated a few extra sections of tower to me and I couldn't resist using them. My signal on the flat side went up to people in my state but most of the DX I had been working at a lower height was gone.

Conditions back then were not favoring long hop skip or coast to coast contacts so I essentially spent a weekend wasting a lot of time and effort to cripple my station. Now I understand how high I want to go is determined by where I want to talk.

One other advantage with the one wavelength height is that it produces the widest vertical beamwidth so it can target a broader range of angles without deep nulls in the pattern that can totally block out certain geographic locations. The tradeoff here is since the lobe is broader it's also not as strong as a narrower beamwidth would be.
 
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