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Message |
    
Airplane1
Advanced Member
Username: Airplane1
Post Number: 976
Registered: 5-2004
| | Posted on Tuesday, April 03, 2007 - 11:10 am: | 
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Hi, Is this possible to do? I would like to cut it down in size to work on 2 meter only so I would think I would need to cut the length and ground plane also.
Anyone know?
thanks,
Airplane |
Tech237
Moderator
Username: Tech237
Post Number: 738
Registered: 4-2004
| | Posted on Wednesday, April 04, 2007 - 10:12 am: |
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DO not try it. It would be a waste of a good antenna. Go and psend the $30 or so and buy a real 2m base antenna, you'll be glad you did.
I have never used a Maco 5/8 BUT as it is a 5/8 antenna you do have a matching network built in and it is designed for 11m and would not work at 2m.
Simon
Tech237
KD7IEB
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Airplane1
Advanced Member
Username: Airplane1
Post Number: 980
Registered: 5-2004
| | Posted on Wednesday, May 02, 2007 - 7:24 am: |
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How would the maco 5/8 tune for 10 meter? would it work ok on that band. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3661
Registered: 7-2004
| | Posted on Wednesday, May 02, 2007 - 10:34 am: |
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roger, i've been using my maco v5/8 on 10 meters(& elsewhere). talked to vanillagorilla, 30+ miles to my east & was every bit as good as on 11m. somebody jumped in another 10 miles east of hank & said i was making a great trip to him. have talked DX to central america & carribbean numerous times on 28.360 & 28.400, 135 watts on my ar3500, 85 watts on my ic706mkIIg, 75 watts on my ic735 & 35 watts on my magnum S9-SWR on maco less then 1.8:1, no tuner. i'm tuned to 27.025, so if i raised it to tune on 27.385, i'd probably be real good on 28.360! just check your swr's-i'll bet you'll be surprised how close it is! |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 981
Registered: 5-2004
| | Posted on Thursday, May 10, 2007 - 2:20 pm: |
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Thanks Patzerozero, I will check it tonight. I think I have it tuned to channel 20. I used it on 10 meter and the watts on the meter fall drasticly so I think it is needing tuned.
I like haveing my call now, I did make one dx contact on 28.400 to south carolina.
Roger |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3691
Registered: 7-2004
| | Posted on Friday, May 11, 2007 - 3:45 pm: |
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just out of curiosity roger, what kind of radio are you using on 10m? depending on how broadbanded the radio is, or where a 'modified' radio is actually tuned, as well as how the radio is designed to handle 'higher' swr will affect output wattage when used out of band-whether the 'out-of-band' band is 11m or 10m. |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 982
Registered: 5-2004
| | Posted on Friday, May 11, 2007 - 7:08 pm: |
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2985dx tuned for 11 meter actuly. I want to get a IC-7000 or IC-746.
Roger |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3695
Registered: 7-2004
| | Posted on Saturday, May 12, 2007 - 10:34 am: |
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the 2985 MAY be aligned & tuned for 11m & therefore show more output at 27.365 then 28.360, even a VERY noticeable difference. IF you were to get a 7000 or 746 & mod them for CB, i'd almost guarantee the output results would be OPPOSITE, higher on 10m & lower on 11m.
oh yeah did you check & compare SWR on 28.360 & 27.205 to see how different they are? if you were at 1.5:1 on CB & 2.5:1 on 10m, the radio MAY cut back some power. the icoms WILL cut back power with 2.5:1 swr. |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 983
Registered: 5-2004
| | Posted on Sunday, May 13, 2007 - 3:00 pm: |
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Ok, I got what your saying on the swr thing.I want to tune my PDL-2 for 10 meter. I think it can be done pretty easy by just shortening the elements a little but how much I will have to experament. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3721
Registered: 7-2004
| | Posted on Sunday, May 13, 2007 - 6:36 pm: |
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avanti/antenna specialists based the pdl 2 quad loops lengths on 492/27.205(or 38.2 feet). if you divide 492 by 28.360 (or whatever freq you want to center on), you'll get the overall length for the copper wire. that should get your swr in the ballpark for 10m. then adjust gamma for lowest swr. |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 984
Registered: 5-2004
| | Posted on Tuesday, May 15, 2007 - 7:10 am: |
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Thank you very much Patzerozero, That is a big help and I wont have to mess up the nice vintage PDL-2. |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 195
Registered: 9-2004
| | Posted on Tuesday, May 15, 2007 - 4:23 pm: |
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Isn,t the formula for a quad loop 1005 divided by the frequency , and the reflector should be 5% longer than the driven loop and the director 5% shorter?
CEF451
Robert L. Spicer
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Marconi
Advanced Member
Username: Marconi
Post Number: 708
Registered: 11-2001
| | Posted on Tuesday, May 15, 2007 - 6:51 pm: |
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Pat00, the PDL does use 38'2" for the wire length, but your formula will not get that answer.
How did you figure your answer?
The formula you show provides a physical 1/2 wavelength, which is 18'.0849" in the case you site. |
Airplane1
Advanced Member
Username: Airplane1
Post Number: 985
Registered: 5-2004
| | Posted on Wednesday, May 16, 2007 - 7:46 am: |
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Yea, it seems to not be working out. Any light shed on the conversion of this PDL-2 to 10 meter I would be very thankful for.
Roger |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3725
Registered: 7-2004
| | Posted on Wednesday, May 16, 2007 - 8:53 am: |
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sleep deprivation, we had just been discussing 2 homemade 3 element beams, built physically identical, at the same time, with parts purchased at the same time from home depot & why 1 tuned R=50, X=2 using 468 to get a 1/2 wavelength but the other tuned the same using 492(feed issues)...anyway, in 1978 as part of a high school communications electronics class, we wrote to avanti regarding their PDL II antenna. is it or is it not a quad-after all, BOTH loops are the same size. a reflector should be about 3.5% longer or a director should be about 3% shorter. the reply was that general radio theory was that 1008/freq got the driven element length. BUT because of the pdl's unique design, feed & matching system, it was far more efficient using the general radio theory of a full wave LOOP as the length for BOTH wires. that number is 1032. the 38.2" number is obtained by using 1032/27.025=38.18 (or 38.2"). we were also informed that the orbital gamma match was far superior to any matching system on the market today. (i ALWAYS tune to 27.025, the incorrect post above to airplane did include 27.205 as a typo. it should've read 27.025. the odd thing that stands out in my head 30 years later, was that the person from avanti said THEY derive 38'2" using CB channel 6 as the focal point, based on a 23 channel band. odd because centering the swr should have been done on 27.110). as is the case with many manufacturers today, their explanation of how the pdl 2 'works' was not much more then 'it does', and why it is better was not much more then 'because it is'. we were NEVER answered-is it a quad?
while i received an 'A' for the class, my time, effort & research for this project only produced a 'B-'. the teacher told me it was because i based it all on CB & not amateur radio. he was an extra back then & we brought xtals from home to put in the aux slot on his 'class-use/demo' ft101 when he wasn't looking...so we could talk dx on channel 6 off our class-built yagi.
very sorry roger....hope you weren't trying to get 1/2 wavelength of wire around your pdl's spreaders  makes for a nasty slingshot effect. |
Ferd1605
Junior Member
Username: Ferd1605
Post Number: 34
Registered: 1-2005
| | Posted on Saturday, May 26, 2007 - 2:30 am: |
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5/8 11 meter antenna on 2 meters ... heck yea .. did it ... i have assembly instructions for a antenna built buy Butternut ... can't recall all the info without a search of my files , but they made a all aluminum antenna that was close to 20 ft tall and fed with a gamma match . It has some "trombone" sections as i remember , and i made mine from solid closeline wire and plastic insulators/support sections .. It must have been a coliner type antenna if i remember right . maybe a Google search for a "Butternut 2 meter antenna" may come up with it , but as i said , i do have the info in my files .. "somewhere" ! |
Tech237
Moderator
Username: Tech237
Post Number: 795
Registered: 4-2004
| | Posted on Saturday, May 26, 2007 - 3:19 pm: |
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Ferd the fed with a gamma match is the secret. A standard 5/8 antenna has a tuned circuit matching network in them and THIS would prohibit using such an antenna on 2m if it was designed for 10 or 11m.
Simon
Tech237
KD7IEB
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Airplane1
Advanced Member
Username: Airplane1
Post Number: 986
Registered: 5-2004
| | Posted on Tuesday, May 29, 2007 - 5:42 pm: |
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thanks ferd, I will search for it but I am going with the pdl 2 setup for 10mete and got a cheapo rad shack 2meter ant for now, it works better than I thought it would. |
Wrk3
Member
Username: Wrk3
Post Number: 93
Registered: 4-2004
| | Posted on Tuesday, October 02, 2007 - 6:18 pm: |
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UVS200 or 300, is a good 2 meter - 70cm antenna...
littleman/cef-354
k5wrk/cef-202
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Airplane1
Senior Member
Username: Airplane1
Post Number: 1015
Registered: 5-2004
| | Posted on Tuesday, October 09, 2007 - 2:47 pm: |
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Got a Diamond X200A duo band and love it. Got the PDL-2 ready for 10 meter and it is going on top of my tower and the Diamond is going on a side arm just below it. How far should the 2 meter Diamond be from the tower, about 2 foot or more?
Roger |
Tech237
Moderator
Username: Tech237
Post Number: 881
Registered: 4-2004
| | Posted on Friday, October 12, 2007 - 11:24 am: |
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18 inches if you want a cardoid or hearthsaped pattern with a null where the tower is or around 36" if you want full circular patter. Both those dimesions assume you are side mounting..
Simon
Tech237
N7AUS
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Airplane1
Senior Member
Username: Airplane1
Post Number: 1018
Registered: 5-2004
| | Posted on Sunday, October 14, 2007 - 5:50 pm: |
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I am side mounting it, I want a round pattern so I will put it at 36 inches from side of tower.
Thanks Tech 237 |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1032
Registered: 5-2004
| | Posted on Saturday, February 23, 2008 - 7:15 pm: |
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Well I found this post by help from Patzerozero and I am very happy. I just could not get my PDL to tune very well and I needed this formula again to see what I did wrong. I some how screwed up the measurments alot,now I figured it again and come up with 36.5 ft wires around the speaders. I hope I got it rigt this time. Weather has been to cold to do any antenna work but should soon get better as spring is getting closer by the day.
No conditions here anyway,
airplane |
Johhn
Intermediate Member
Username: Johhn
Post Number: 146
Registered: 8-2007
| | Posted on Sunday, June 22, 2008 - 2:48 pm: |
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The MFJ 971 Antenna Tunner Work's very well
for this. I go from 20.000 to 29.965 mhz.
Rci 2950 dx unlocked. All band.
I don't leave the house too re-tune the antenna. |
Bruce
Senior Member
Username: Bruce
Post Number: 4740
Registered: 9-2003
| | Posted on Sunday, June 22, 2008 - 5:16 pm: |
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Diamond X200A ..... nice antenna ......I use a V2000 for 6, 2 and 444 vertical.
On 6 since 66
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Airplane1
Senior Member
Username: Airplane1
Post Number: 1082
Registered: 5-2004
| | Posted on Thursday, October 09, 2008 - 1:58 pm: |
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Let me bring this PDL-2 conversion question in this thread to the top one more time.
How critical is the lenth of wire running around the PDL-2 elements??? Would a quarter to half an inch off either way be a big problem with tuning the antenna or will there be enough adjustment in the gamma matches to make up for the wire length?
I seem to be having a little problem tuning it to 1-1 swr or will it never tune that good?
It only tunes 2.8 on horizontal and 2.1 on vertical on 28.400. I came up with 36.3 feet of wire and then devided it by 4 to get the marks for attaching it to the spreaders.
Maybe it is not a good antenna for 10 meter ops but I was sure Avanti made a 10 meter version that was the same antenna just shorter wires.
Thanks
AP |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4411
Registered: 7-2004
| | Posted on Friday, October 10, 2008 - 6:38 pm: |
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roger, check swr on 28.300, then on 28.500. if you have an antenna analyzer, you can check for where the antenna is actually tuned to, & and adjust length accordingly. though you're not 'supposed to', tune around & see where the swr is actually the lowest, & just how low it is, then check what freqs your swr is 2:1 at, both above & below the low point. if it is higher on .500, then the wires are too long. if swr is higher on .300, then they are too short. been a long time since i played with a pdl2, but, yes, an inch or 2 could change swr from 2:1 to 1.7:1. or more, or less.
maybe a bit oversimplified, but, length adjustments are to get you to freq you want antenna resonant on, then match adjustments fine tune R & X to get the best 'match'.
reading the instruction manual for an mfj259b is actually a pretty good primer on antenna tuning, even if you don't have one. you can download it from mfj's site. there are also a few books that simplify what these things mean, while many are written for an engineer. |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1140
Registered: 5-2004
| | Posted on Tuesday, December 16, 2008 - 11:39 am: |
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Any one out there use a pdl 2 on 10 meters? I want to know if this is worth it to convert or wasted time. Should I just buy a 3 or 4 element 10 meter antenna? I could sell the pdl and the money I get buy an antennas made for 10 meters.
I ran out of time this year to finnish the conversion of it till spring.
I do have a mfj-259 not b version to learn how to use. It is simple to ajust swr on the anilizer but I need to understand how the other things do like tuning to 1.1 swr and at that freq. it is resonant but then z= I dont understand. the manual is a bit greek to me.
when I tune up or down the band with my maco it shows the ohms going up and down and not staying at 50.
can someone help me understand? my maco 5/8 is tuned at 28.893mhz 1.1 swr and I am going to change the length up till it is tuned at 28.400 mhz and 1.1 swr. can I then tune it better with the 259 like with the z= ?.
Sorry if this is showing my lack of understanding but I got the 259 analizer to be able to set my antennas and system up the best it can be.
AP |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 493
Registered: 9-2004
| | Posted on Tuesday, December 16, 2008 - 7:59 pm: |
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It depends where you are going to spend most of your time.If you want to stay on 10 then tune it for 10 and use a tuner on 11 . I used to use my 6 element for 10, on 11 with auto tuner and it worked fine,only difference was the front to back and front to side were off a little.The SWR not (SWR's whatever that is ) was easily tuned down with the auto tuner in the 920.
Bob
Robert L. Spicer The days of radio are just beginning!
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Ferd1605
Junior Member
Username: Ferd1605
Post Number: 43
Registered: 1-2005
| | Posted on Wednesday, July 14, 2010 - 12:55 am: |
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am many years late on looking this up .. but the antenna i described in my post here way back when is a Buttenut 2MCV-5 .. it is a collinear desighn .. looking at the diagram , loos like it is about 15 1/5 ft tall .. i took a old 11 mete 5/8 wave and built one using the original manual .. worked VERY well .. think i may have to build another one up .. maybe scale it down and build one for 440 also .. |
