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Message |
    
Airplane1
Senior Member
Username: Airplane1
Post Number: 1046
Registered: 5-2004
| | Posted on Tuesday, June 03, 2008 - 7:51 am: | 
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Would I use the same formula to set up the moonraker 4 for 10 as I would for the pdl-2?
Would I need to change the length of all the elements or just the driven ones?
I got a nice moonraker from a friend of my dads and thought of useing it for 10 meters. |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 401
Registered: 9-2004
| | Posted on Tuesday, June 03, 2008 - 3:53 pm: |
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If you are going to use it only on 10 meters than change the length on all elements if using it in 10 and 11 leave it as is and use a tuner.A lot of people use 11 meters yagis and quads on 10 meters and they will work but the front to back ratio and front to side will not be as good.I used to use my homebrew 6 element for 10 meters on 11 with a tuner, didn't bother changing anything because 10 meters is my band of choice 11 meters second.
Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
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Marconi
Advanced Member
Username: Marconi
Post Number: 766
Registered: 11-2001
| | Posted on Wednesday, June 04, 2008 - 7:14 am: |
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Airplane, you have to know that the PDL is a quad antenna the the moonraker is a yagi. If you have such a conversion formula process worked out for the PDL it will not accomadate the other.
To go towards 10 meters with the MR'r means you should need to make the antenna elements smaller and generally that is the idea. But, because the moonraker uses wire tips in their design you may find it difficult to control the reactance at the desired frequency you wish to reach. All of the components of this antenna were designed to size, shape, and dimension in order to control the reactance within a range that the gamma could reach a match at the desired resonant frequency.
A comment in case you go forward with this mode on the MR. The easy thing to do would be to just slide the center section of each yagi element in a bit closer attempting to raise the frequency towards 10 meters. That may happen, but you may also loose control over the reactance in the antenna and not be able to get a good match. I have found the MR'r to work fine as designed and built, but they are hard to modify, and it may be because of this mix of materials and/or the significant size difference in the tapper.
Good luck, and keep us up-to-date on your progress. |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 403
Registered: 9-2004
| | Posted on Wednesday, June 04, 2008 - 8:57 pm: |
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Too bad the mr didn't have a quad loop that was driven then it would be classed as a quagi,cross between yagi and quad now that would be interesting.
Bob VE1CZ/CEF451
Robert L. Spicer The days of radio are just beginning!
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Airplane1
Senior Member
Username: Airplane1
Post Number: 1047
Registered: 5-2004
| | Posted on Thursday, June 05, 2008 - 7:19 am: |
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I was talking to someone in my area that is using a MR on 10 and just uses a tuner. He said it works great and tunes easy with the tuner.
I probably will just do this as I dont have the time to mess with it if it is complicated.
How much do you lose using a tuner on 10 meter compared to 11 meters? I would not think it would be to bad. |
Marconi
Advanced Member
Username: Marconi
Post Number: 767
Registered: 11-2001
| | Posted on Thursday, June 05, 2008 - 1:37 pm: |
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I would agree that the tuner idea is better. I'm not sure how much loss you will have. Maybe you won't even be able to tell just operating your radio.
I would try to get a good tuner though. |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1048
Registered: 5-2004
| | Posted on Friday, June 06, 2008 - 8:18 am: |
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Marconi, I have an IC-7000 with a LDG AT-7000 tuner. I use a maco 5/8 for 10 now and it tunes it great to 1.1-1.2 at 28.400.
I here they are pretty good tunners so I think it will work with the MR.
Did you hear anything of the AT-7000 tunners??
Thanks |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4272
Registered: 7-2004
| | Posted on Friday, June 06, 2008 - 7:01 pm: |
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'How much do you lose using a tuner on 10 meter compared to 11 meters?'-roger, this may give you an idea of what you will lose-approximately.....i think you already realize that an antenna resonant & matched to 1 band is superior on that band as compared to when you use a tuner to put it on another band. the tuner is just 'tricking' the radio into thinking it is using a matched antenna. sure, 100 watts into a 1.1:1 load will give some decent erp #'s, but put that 100 watts into an inferior antenna, and erp suffers substantially. 11m to 10m isn't all that bad, but a quality tuner can make a coathanger tune up on 160m.....GUARANTEED to do a good job on 2m, but you ain't goin' nowhere on 160-no matter what the meter says!
check where your swr is 'best', then check it on the 10m freq you expect to be'centered on'. go to a site such as http://www.ocarc.ca/coax.htm and plug in the pertinent numbers. compare the db losses and/or power in/power out numbers & it'll give you an idea of how much you may or may not be losing.
even if you are 1.1:1 on cb & 2:1 on 10m, you probably won't find much real world difference in signal. local talking vs skip, 11m vs 10m is going to be hard to 'tell' a difference-you'll find a 100w signal into a 1.1:1 dipole on cb vs the same with the antenna matched on 10m, will PROBABLY be NOTICEABLY 'stronger' on 10 then 11. why? noise & overcrowded freqs, operators that don't stand by on 11 like on 10, etc. |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1049
Registered: 5-2004
| | Posted on Wednesday, June 11, 2008 - 2:10 pm: |
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Marconi, Patzerozero and Captian_radio.
Thanks for the info. great help. |
