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Tech808
Moderator
Username: Tech808
Post Number: 6818
Registered: 8-2002
| | Posted on Thursday, August 25, 2005 - 11:43 pm: | 
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This Topic has been moved here from the Open Area Forum.
Lon
Tech808
CEF808
N9OSN |
Mrclean
Junior Member
Username: Mrclean
Post Number: 11
Registered: 12-2003
| | Posted on Thursday, August 25, 2005 - 4:18 am: |
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I have found a new Pdl2 and Two Astrobeams all for a good price. Im leaning toward the PDL 2 to put up this fall as it has vert and horz. Who has used either or both and which would you favor. Guess I will sell the ones i don't put up but for the price im paying may just keep um. |
Dude1218
New member
Username: Dude1218
Post Number: 8
Registered: 11-2002
| | Posted on Thursday, August 25, 2005 - 10:22 am: |
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Mrclean:
I had a Astrobeam up since '79 or 80 till i moved and couldnt take it with me.
It did a great job.
As for the PDL2 i couldnt tell you about it as i never used one but know several people that had them and liked them
good luck on either you choose to use
Dude |
Tech833
Moderator
Username: Tech833
Post Number: 1056
Registered: 8-2002
| | Posted on Thursday, August 25, 2005 - 10:47 am: |
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The Astro Beam will have a little more gain, but the PDL 2 will give you both polarities. Also, the PDL 2 has almost the same amunt of signal front and side. However, the back side rejection is good. The Astro Beam will have a more narrow major lobe. |
Road_warrior
Advanced Member
Username: Road_warrior
Post Number: 779
Registered: 7-2004
| | Posted on Thursday, August 25, 2005 - 12:24 pm: |
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PDL-2 works good. Never seen or heard a Astro-beam
in action,so, not much i can say on that beam.
Best of luck with whatever you do....
Jim/CEF 375
Central PA.
RCI 2995dx base
I-10K Antenna |
Yankee
Advanced Member
Username: Yankee
Post Number: 844
Registered: 7-2003
| | Posted on Thursday, August 25, 2005 - 12:31 pm: |
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I have a PDL-ll in the air and I'm very pleased with it's performance. I have an almost flat match on both vertical and horizontal.
I run horizontal most of the time on DX and get very good reports.
I know nothing of the Astrobeam, but have talked to stations running them and they seemed to be doing ok. But, there is an old saying, "flat is where it's at". Also with an antenna tuner the PDL-ll can do 10 meters-15 meters with very good results. 20 meters is some times possible. Also most of HF amateur radio is run on horizontal except for mobiles. Therefore if you are licensed or plan on getting your license, the PDL-ll is the better choice.
Just my 2 cents worth.
Carl KD5SDM/CEF-357 |
Mrclean
Junior Member
Username: Mrclean
Post Number: 12
Registered: 12-2003
| | Posted on Thursday, August 25, 2005 - 12:59 pm: |
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What would be a fair price for me to pay for the astros. I am putting up the PDL 2. Thats the way I was leaning anyway. Think I will get the astros and try to make afew bucks. A guy here runs the PDL2 with a big Ameritron and walks the dog. He has ran both the PDL2 and the Moonraker 4 and for overall ease of keeping up evreything else prefers the smaller true Quad. I figure if I got conditions the antenna will do fine. Going to try and get it up 50 or 60 feet. How much better is the Mooraker? |
Kb9umt_don_123
Junior Member
Username: Kb9umt_don_123
Post Number: 28
Registered: 3-2004
| | Posted on Friday, August 26, 2005 - 8:07 am: |
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Brian-MrClean,
I will take a shot at this, it's been awhile but years ago ran most every antenna they made, so yes I have operated from both the Avanti Astro Beam AV-150 and Avanti PDL-II AV122. If I remember right the Astro Beam was advertised at around 11 dbi with 40db front-to-back, and the PDL-II around 10.5 or 11 dbi also with front-to-back around 25db or so. Both antennas I had at about 2 wavelengths or 72 feet. The Astro Beam is a 3 element beam vertical only and if you were looking for REJECTION or tuning out interference it would be a good antenna, the only draw back to me is the way it's matched..can be touchy if not done to the 't'. The PDL-II is a small quad of sorts (not a true quad) and it has 2 elements and has both horizontal and vertical and I would bet very little difference in gain from the Astro Beam. The advantage of the PDL-II is the dual polarity (horz-vert) the disadvantage is the fact that it has poor front-to-back (I think more like 15db to 20db at best...sides are better as mentioned by Tech833). If I had to choose between the two antennas the PDL-II would be the choice (actually I did back then and the PDL-II did stay on the tower at that time). I think you might still find some PDL-II's for sale going from maybe $50 to $100 used to $150 to $200 if new in the box (it's been a while so my $ might be off)...the Astro Beam goes for less on the market from what I have seen. I would think a 'fair' price would greatly depend on if all the parts are there and the conditions of both antennas, I would let the person selling set the 'fair' price and if $40 bucks for both is good with them..then buy them… if they say $50 for each then I would maybe walk or counter...just my view on that.
Wrk3 gave you a very good reference site linkNow...since we went over the antennas themselves some let's cover a few other things while on the subject. Many have tried the added wires to increase rejection on the PDL-II's or MoonRaker4/6...my experience is 'been there and done that' and DON'T. What you might gain in the back you might take from the front and also just increase your wind load and also if you are in the area of the world with snow/ice you will have problems with icing. Also keep in mind when handling the fiberglass elements to wear gloves or those little fibers will be in your hands. When putting your antenna up, please remember a few things...not only ANTENNA ANTENNA ANTENNA that counts in radio but also HEIGHT and LOCATION...if you are on a high hill it will make radio fun at 36 feet but if you are in a bad location then go up as high as you can safely or legally to increase your ground wave coverage...but then again maybe no one really does ground wave anymore. Back when the band was not active the ground wave distance was much more of a match of 'who had what' on the tower...most of us were also horizontal because vertical had less man made noise and the signal traveled a tad further...so yes horizontal has advantages. Another advantage of horizontal is if another station has horizontal also and you have vertical interference on the band you both can switch and have a 20db decrease in that vertical interfering signal...very nice to have that. A factor to also keep in mind is the fact that your antenna makes a difference but your WHOLE ANTENNA SYSTEM needs to be addressed...make sure you use good low loss coax and connectors...it could make a 1db to 2db difference alone. Also make sure to weather proof your connections because moisture is your worst factor and once up you don't want to have to do antenna work twice, do it right the first time.
Your last question was about a Moonraker4 and it also is a great antenna in my view and I've had a few of them (hubs I can say not the best over years and years of time but drill them into place and should be good)...the Moonraker4 I think has about 14.5dbi gain (advertised anyway) and around 30db or so front-to-back, also vert/horz and better on the side rejection. So from going from a PDL-II to a Moonraker4 you will see about a 3db gain or 1/2 sunit on a properly calibrated meter..not much but if you are talking weaksignal work it might be the difference of a contact and not a contact. Another thing that really put the PDL-II as a contender in my book was stacking them, by stacking them you get the 3db gain so your up to about a Moonraker4 gain...and you really get a good pattern and true 40db front-to-back for great rejection for interference (the PDL-II's are small enough to stack and a good Med/Large rotor to handle that load...Moonraker4 stacked are great also but hard to handle, big big wind load and a large rotor is a must). Just an option on the stacking but it really makes the PDL-IIs work well.
I think Carl/Yankee/KD5SDM mentioned about tuning a PDL-II for 10mtr thru 15mtrs...you might tune that antenna for that with a good tuner but I would wonder what the comparison would be to a tuned dipole for 17 or 15 meters...?? I would think the PDL-II would tune fine on 10mtrs the CB band of course and also the 12mtr band..not sure on the other claims. I do know that many Hams convert the PDL-II to 6 mtrs and shorten it but use it as a true quad. I also would like to correct "Also most of HF amateur radio is run on horizontal except for mobiles", that is not true, there are just as many on ground mounted or raised verticals on HF as there are with horizontal antennas...the propagation goes one way then the other at times so to say one is better over the other I'm not sure is a true statement....there also is a big big factor in all this and that's your antenna's TAKE OFF ANGLE.
Thanks for letting me post.
de kb9umt Don
http://www.HamRadioHelp.com
maybe we can get into TAKE OFF ANGLE and db vs dbi vs dbd sometime also
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Yankee
Advanced Member
Username: Yankee
Post Number: 851
Registered: 7-2003
| | Posted on Sunday, August 28, 2005 - 12:18 am: |
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Don, Very well presented. The previous owner of my PDL-ll has his extra license and he ran the PDL-ll with the same tuner that I have. He worked 10-15 meters through out the world and reported that he some times was able to get the beam to work 20 meters within 1500 miles. After being on the air myself for 42 plus years and owning another PDL-ll back home in upstate New York and ran horizontal 90% of the time and having worked all but I think something like 3 states, and since my move to Oklahoma I have worked all states from my present location and most of those states were with an IMAX-2000, before I was lucky enough to get the PDL-ll and tuner.
Thank you for your concern and such a great post.
Carl CEF-357 |
Kb9umt_don_123
Junior Member
Username: Kb9umt_don_123
Post Number: 29
Registered: 3-2004
| | Posted on Sunday, August 28, 2005 - 8:16 pm: |
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Carl/Yankee/KD5SDM/CEF-357
Thanks……I appreciate your reply. I also share your long time experiences in ‘radio’ and have ‘been there and done that’ just like you (been around the block a few times, and sometimes dragged a few times around). Below are few main points from I would like to touch on mainly for those that might be new to ‘radio’ be it CB or Ham Radio…or new to antennas/propagation:
- “most of HF amateur radio is run on horizontal except for mobiles” & “I ran horizontal 90% of the time”, I want to make clear to those that might be new to Ham Radio HF bands why horizontal for DX may or may not help.
Since most HF propagation is ionospheric, polarization doesn't really matter much (again this is for HF Dx/skip). The ionospheric reflection is constant only in that it's continuously changing! How and where the signal is bounced/skipped from is a key factor and what goes up as horizontal polarization may not come down as horizontal but change back and forth from vertical to horizontal due to many factors/and/reflection. Also some might actually want a vertical antenna due to is lower angle of radiation which is good for DX/skip but other times it’s good to have an antenna like a horizontal wire dipole closer to the ground were it might have a high angle of radiation that would enable just contacts a few hundred miles out….your antenna plays a big roll on how far you will reach out and the contacts you will make (that’s why Hams will have many types of antennas, and maybe even for one band). I will not go into much depth on that but will give anyone reading some links for propagation and or effects of:
http://ecjones.org/propag.html
http://www.ae4rv.com/tn/propflash.htm
http://www.beaconoftruth.com/indices.htm
http://www.geocities.com/w5dxs/propagation.htm
- Using a tuner with an antenna not designed for the specific band it was intended for….statements that ‘my antenna works’
Although I have no doubt that the PDL-II with an antenna tuner (wide range antenna tuner not a ‘touch up’ tuner) will tune from 10 meter down to 20 meters there are a few things to understand. What is the antenna tuner doing? Your radio wants to see a 50ohm match and that tuner is letting your radio see the match it wants to produce the power from the rig that is ‘normal’….yet you have changed nothing on the other end of the equation…the antenna! So your statement that this antenna can be tuned for other bands is true…I would even bet my old Dentron MT3000 would tune it just about anywhere on HF from 10 to 80 meters, but what signal is actually produced out to the antenna is another story (using 50ohm coax you are losing most your signal in the coax/). So, do I believe that the antenna will work on other bands using an antenna tuner…sure do….but how well? It might work very well, but how do you know unless you have another antenna as reference? So if you had a dipole cut for 15 meters or 20 meters as a reference antenna you might see how well your ‘tuned’ CB PDL-II antenna really works or doesn’t work since you would then have a reference antenna to compare signals. As far as your comment that the previous owner of your PDL-II was an ‘EXTRA’ class Ham license really doesn’t change my mind in what I’m telling you, I’m sure he was very knowledgeable and knows all this but I for one don’t get to caught up on the ‘class’ thing as I have ‘radio’d’ with many of my CB buddies over the years that new a lot more than some Extra class ops I’ve been around and I also know many Techs that no double know more about ‘radio’ fundamentals than some Extras….also know some darn smart Novice, Tech Plus, Advanced, and Extras…but again I don’t really put much in what ‘class’ they have but I do listen to those that know what they are talking about no matter the class or even if they hold a Ham license….there is much to learn about all this and I for don’t claim to know much but do try to learn or share everyday something ‘radio’ related….we all have a great lifetime hobby and those who are truly interested are learning as we go.
- Comparisons between the antenna and what DX you have worked
“I worked WAS (Worked All States) or DXCC with this antenna” is a statement that can be made by many with some very poor antennas, so why is this? Propagation/Band Conditions sometimes is the key and using just about any kind of antenna can and will work. In just a few hours of operation on a Holiday weekend I put a 30 ft or so random wire BELOW GROUND level and INSIDE my basement using the antenna tuner and 5 to 10 watts QRP and worked some 23 States and 2 countries….does that mean that my antenna is working well? Not really, but at the time with the propagation at hand I was able to work a number of folks on this really poor antenna setup. For someone to post that I worked WAS or DXCC on a basement antenna or I worked from 10 to 80 meters on a CB antenna with lots of contacts could be true….sure you can…but if you had a reference antenna to compare what you were missing out on you would find that maybe the antenna you were using was not only poor but you could not even hear many of the stations that a simple dipole cut for band was hearing. Any antenna is better than no antenna, but remember when reading other postings about antennas that they may or may not understand antennas/theory nor have any comparisons to conclude a result favorable for you to just do the same thing hoping for good results. Also, propagation and Solar Cycle has so much to do with radio signals…..wait a few years when the cycle is back to its peak and you will find again on 10 meters and the CB bands that a wet noodle and a few watts will produce plenty of DX contacts…..at the cycle lows you will find that if you are not a Ham and able to go lower on the bands to find better propagation/DX then you will have to increase your antenna gain on the higher bands and even then sometimes the band conditions just aren’t there.
Carl, I know most of this you already know with the number of years you have in radio but a review of a few facts might be good for others or those new to ‘radio’ if they truly are wanting to know more about how things work and why. If you get a chance Carl (or anyone else that might be a Tech reading this) I don’t know if you are a General with HF but if not please think about taking the written test NOW because I’m sure sometime within the next year (2006/2007) the code will be dropped and having the written General (element 3) part of the test completed might put you in a better position for a possible automatic upgrade at the time of the changes (you have a nice setup Carl from what I have read and I know you are very interested in radio and this hobby, so best of DX to you my friend). Thanks again for letting me post here.
De kb9umt Don
http://www.HamRadioHelp.com
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Airplane1
Advanced Member
Username: Airplane1
Post Number: 811
Registered: 5-2004
| | Posted on Sunday, June 25, 2006 - 7:01 pm: |
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De kb9umt Don,
Can you enlighten me on how to stack PDL-2s? Is that mounting them side by side or on top of one another?
Would a 10.5 sq ft rotor be enoght to turn stacked PDLs?
Hope you can answer these questions for me.
Thanks,
AP |
Wildrat
Advanced Member
Username: Wildrat
Post Number: 917
Registered: 12-2003
| | Posted on Sunday, June 25, 2006 - 7:43 pm: |
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Long ago I had a astroplane then went to a pdl-2. With that small beam I spoke all over the world without any problem at all. I did have a golden eagle tube amp, only about 800 max. i loved that old beam, wish I still had it. The astroplane worked OK, so I kept it for local chatting.
WR |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3028
Registered: 7-2004
| | Posted on Sunday, June 25, 2006 - 10:02 pm: |
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pdl's would go side by side, with a boom running from mast-mount to mast-mount, sort of looking like this, with 1 mast in between 'em:
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Rldrake
Intermediate Member
Username: Rldrake
Post Number: 181
Registered: 1-2006
| | Posted on Sunday, June 25, 2006 - 10:32 pm: |
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Stacking a pair antennas that have the ability to be switched between vertical and horizontal polarity is a rather odd plan.
Normally, when stacking a yagi, quagi, or a quad...the antennas being stacked would be one above the other on the mast when oriented in the standard horizontal polarized position.
If the stacked pair were going to be used as vertically polarized antennas...they are normally mounted on a cross-boom, broadside to each other. |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 812
Registered: 5-2004
| | Posted on Monday, June 26, 2006 - 7:27 am: |
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I dont think I will ever stack my two PDLs but I want all the info anyway. What is the spacing between them and how would I go about hooking the coax up?
Can someone please give me all this info so I can print it and keep it in case I get motivated to do this?
And what rotor would work? I have a Alliance HD73 rotor here I could use if it`s strong enough.
Thanks in advance,
Roger |
Tech291
Moderator
Username: Tech291
Post Number: 403
Registered: 11-2004
| | Posted on Monday, June 26, 2006 - 9:25 pm: |
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Roger,
Hate to dissapoint you,but having experience with stacking PDL-2's I wouldnt recommend it.
#1,your HD-73 will not handle the braking torque of the stacked set.
#2,the Avanti stacking kit(same as used with the MR-4 and 6)is probley more scarce than the PDL's.
#3,hardest to tune(swr)setup I have messed with.
#4,without a crane,the hardest balancing act I ever did on top of a tower!
#5,gain(3db)is not worth the headachs.
If memory serves me,the stacking boom was around 24' long itself.as far as cables,you would need 2 standard co-phase harnesses,connecting both verticals to 1 coax leadin and connecting both horizontals to the second leadin.because of the braking torque being transmitted to the tower,dont think I would use anything less then Rohn 45 or its equivelent.
I'm sure someone out there will dissagree with some or all the points I made,but to me it just isnt worth it.
TECH291
CEF#291/CVC#6
KC8ZPJ |
Road_warrior
Senior Member
Username: Road_warrior
Post Number: 1677
Registered: 7-2004
| | Posted on Monday, June 26, 2006 - 10:21 pm: |
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I agree with all your points Tech291.
It would also be alot easier to just go with a larger beam. |
Yankee
Senior Member
Username: Yankee
Post Number: 1256
Registered: 7-2003
| | Posted on Tuesday, June 27, 2006 - 12:16 am: |
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I honestly agree with my friend Dennis. What little gain you would get from a second PDL-ll is not worth the trouble and what it might cost to do it.
I run a single PDL-ll and do one heck of a job of making contacts with it. About 24 foot 4 inches off the ground, counting the measurement of the rotor to the boom of the antenna.
I wouldn't dare go any higher with it, because of the strong winds we get.
Mother nature has been good to me, I live out in the open on a small hill. |
Dale
Advanced Member
Username: Dale
Post Number: 532
Registered: 12-2002
| | Posted on Tuesday, June 27, 2006 - 12:27 pm: |
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yea i agree stacking would be more hassle then its worth.now i had locals here with pdl2 and astro beams both 2 guys talk great ony problem
occued the guy with pdl2 coulnt get the flatside below a 2.1 dont know why though |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 814
Registered: 5-2004
| | Posted on Wednesday, June 28, 2006 - 10:09 am: |
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Thank for all the info. I will def. forget about doing that idea. I will just put the one pdl-2 up and be done.
AP |
