| Author |
Message |
    
Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 14
Registered: 4-2009
| | Posted on Sunday, May 03, 2009 - 10:39 pm: | 
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hay yall.
I would like to get another cb base antenna I currently have an antron A-99. I would like to get the best bang for my buck.what type would be best??? I was thinking about a 3 element beam. |
Bruce
Senior Member
Username: Bruce
Post Number: 5039
Registered: 9-2003
| | Posted on Monday, May 04, 2009 - 8:49 am: |
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3 to 4 elm beam is best for the buck ...
On 6 since 66
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Ssr
New member
Username: Ssr
Post Number: 9
Registered: 4-2009
| | Posted on Monday, May 04, 2009 - 9:02 am: |
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i will let the actual experts give recomandations, however i would suggest you add a couple things,
i assume you are keeping the a99 and adding another, what is the purpose of the new ant? are you looking to shoot skip, get farther out locally? are there space/height restrictions?
are you replaceing the a99?
whats the budget?
theres alot to consider in ant selection, the more info the better to make a good recommendation. |
Bruce
Senior Member
Username: Bruce
Post Number: 5040
Registered: 9-2003
| | Posted on Monday, May 04, 2009 - 9:27 am: |
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GAIN on a 3 elm beam is about 6 DBD on a 9 foot boom ..... Gain on a 4 elm beam is about 7DBD on a 14 foot boom....
NOW if you want to go up 1/2 "S" unit you have to go to a 28 foot boom and 6-7 elms.
THEN you have to figure how your going to turn it ... small beams turn with a TV rotor larger ones take a HAM M ( $400 to 800 ) and a good size tower to support it.
Dr.YAGI and DR. UDA 70 years ago figured this out and even with computer added design no one has done much better.
For 40 years I have ran 3 and 4 elm beams on 6 and 2 meters with very good results ....
Now you CAN make a directional antenna out of 2 A-99's but at best its tricky ....
http://www.hy-gain.com/man/pdf/AV-12AVQ.pdf
This manual about page 20 shows how to phaes 2 antennas again its not just runing a coax ....
Look around and see what is out there and
FEEL FREE TO ASK QUESTIONS !
Bruce
On 6 since 66
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Tech237
Moderator
Username: Tech237
Post Number: 1155
Registered: 4-2004
| | Posted on Monday, May 04, 2009 - 11:50 am: |
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Beams are good, but may have forgotten something, and that is a 3 el Quad has slightly more gain than a 3 el beam on the same boom length.
Admittedly beams for CB are available commercially, and I am not too sure about Quads (all mine have been homebrewed).
If you really want experiment a bit, and have some free space, you could always try things like colinear arrays or curtains, which can be built for less than a beam and can have the same gain only in fixed directions though.
Simon
Tech237
N7AUS
.
I thought he said, "there was no rust for the wicked, and I own an MGB"
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Olde_timer_669
Junior Member
Username: Olde_timer_669
Post Number: 43
Registered: 8-2007
| | Posted on Monday, May 04, 2009 - 6:27 pm: |
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If you are thinking about a Yagi Beam, Considering size & gain I would think 4 elements
Ron
Olde Timer 669
CEF 940/Ham 264
Quincy Illinois
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 15
Registered: 4-2009
| | Posted on Monday, May 04, 2009 - 7:02 pm: |
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thanks I am still new to directional antennas.
is vertical mounting better than horizontal????
I hate to seem like a dummy but can you explain co phasing two cb antennas better please. from my understanding you need equil lengths of coax to the antennas and thats about it sry |
Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 16
Registered: 4-2009
| | Posted on Monday, May 04, 2009 - 7:15 pm: |
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I was thinking about a maco m103-c but not sure about the best antenna to get I wanted one that would give me at least times 20 multiplication so I can do better on long range talking. |
Starface
Senior Member
Username: Starface
Post Number: 2426
Registered: 1-2005
| | Posted on Monday, May 04, 2009 - 8:18 pm: |
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Local Vertical
DX Vorizontal
George
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Moderator136
Moderator
Username: Moderator136
Post Number: 1471
Registered: 4-2005
| | Posted on Monday, May 04, 2009 - 9:08 pm: |
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Hi Flying_cloud
I have owned a Maco 103 in the past and at this time a Maco 105 in the air. The Maco 103 you can use a tv rotor and they work great and Copper sell's them also. As said in a above post you have to have a bigger rotor and are not cheap, My 5 element beam has cde rotor with brake. To put it simple: Vertical to vertical.. Horizontal to horizontal. I have less noise on horizontal beam than the vertical Imax 2000. Now about your question on gain the Maco 103 around 9 or 10 . Around 6 db. My 105 gain around 14 db - 28 foot boom and so called power gain 40 times the output. I hope im right in given you the answers im doing by memory and math in my head. Also depends on coax loss and switches , tuners , amps and a whole bunch of factors. I hope i helped in some way.
73
Hal~Moderator136~KCØSVC
CEF#0136/CEF HAM#23 ~ CVC#0004
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 17
Registered: 4-2009
| | Posted on Monday, May 04, 2009 - 9:44 pm: |
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so I should mount it horizontal for dx and it will have less noise. and with a maco m103-c I can use a tv rotor but any thing bigger I will have to get a bigger rotor. |
Dale
Senior Member
Username: Dale
Post Number: 1482
Registered: 12-2002
| | Posted on Tuesday, May 05, 2009 - 10:10 am: |
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yes get the 103 mount it horizonally then get
a imax2k or maco5/8,sirio2016 for a verticle
and mount it above it.talking locally with beams
to me seems more trouble than its worth constancly turning beams and people hollaring
for ya and cant hear them cause beams arent pointed right direction.not to mention the extra
wear and tear on a rotar turning the beam every
5-10 minutes.just use/get a ground for verticle/local use.just my 2 cents worth
dale/a.k.a.hotrod
cef426
cvc#64
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Starface
Senior Member
Username: Starface
Post Number: 2428
Registered: 1-2005
| | Posted on Tuesday, May 05, 2009 - 11:11 pm: |
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Dale I agree, get the 103 mount it horizonally then get
a imax2k or maco5/8,sirio2016 for a verticle.
George
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 20
Registered: 4-2009
| | Posted on Wednesday, May 06, 2009 - 1:58 am: |
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instead fo that could I use the antron a99 for local and use the beam for dx just co phase them or would that not work?? |
Moderator136
Moderator
Username: Moderator136
Post Number: 1474
Registered: 4-2005
| | Posted on Tuesday, May 05, 2009 - 9:10 pm: |
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Hi again Flying _ Cloud
Yes again the Maco 103 will do what you want it to do. And a light rotor from Copper will work fine also.
Hal~Moderator136~KCØSVC
CEF#0136/CEF HAM#23 ~ CVC#0004
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Airplane1
Senior Member
Username: Airplane1
Post Number: 1211
Registered: 5-2004
| | Posted on Wednesday, May 06, 2009 - 9:17 am: |
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Keep your 99 and mount it above the 103c mounted horizontal and use a tv rotor. you can get them from copper and you will have a great local/DX setup.
Oh yea, try to get the beam 36 ft to boom if you can. |
Big_m
Member
Username: Big_m
Post Number: 67
Registered: 9-2007
| | Posted on Wednesday, May 06, 2009 - 9:11 am: |
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Flying Cloud yes you can use your A99 above the Maco 103. Just mount the A99 about 2-3 feet above the Maco. And it will work great. |
Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 21
Registered: 4-2009
| | Posted on Wednesday, May 06, 2009 - 3:39 pm: |
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ok thanks yall sorry for the trouble like i said earlier i am still learning on the raido stuff thanks |
Dale
Senior Member
Username: Dale
Post Number: 1483
Registered: 12-2002
| | Posted on Wednesday, May 06, 2009 - 10:07 pm: |
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sorry cloud didnt see ya already had an a-99
yes it will work.i got many locals here that
use this exact type of setup
dale/a.k.a.hotrod
cef426
cvc#64
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 22
Registered: 4-2009
| | Posted on Thursday, May 07, 2009 - 9:30 pm: |
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airplane what do you mean when you say to get the beam 36 ft to boom if you can? |
Bruce
Senior Member
Username: Bruce
Post Number: 5051
Registered: 9-2003
| | Posted on Friday, May 08, 2009 - 5:59 am: |
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Above the ground some antennas can be effected by how high up they are
On 6 since 66
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 23
Registered: 4-2009
| | Posted on Friday, May 08, 2009 - 9:28 pm: |
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thanks bruce so i should mount it 36' in the air at least |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1213
Registered: 5-2004
| | Posted on Monday, May 11, 2009 - 7:17 am: |
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Flying cloud,
Most people say to get the antenna up at least a wave length, 36 ft from ground to where your beam antenna connects to the mast. It helps the take off angle to be lower which helps you get out better than if you mount it lower and shoot your signal up in the sky at a higher angle. I had my antenna at 7 ft on a temp. mount just to get on the air fast. When I got it up on the tower 36 ft I did much much better ground wave and DX. it is like skiping a stone on water, if you throw the stone on a lower angle at the water the stone skips farther. This is what I learned on here.
This is why I say to get at least 36 ft.
Hope this helps. |
Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 25
Registered: 4-2009
| | Posted on Wednesday, May 13, 2009 - 3:26 pm: |
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thanks airplane |
Keithinatlanta
Advanced Member
Username: Keithinatlanta
Post Number: 831
Registered: 3-2003
| | Posted on Thursday, May 14, 2009 - 7:08 am: |
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Ok guys, now you can educate me. What if the beam is mounted on a 50' push up pole? Does that help to be higher or is 36' the magic number? Thanks.
Keith in Atlanta
CEF 150 |
Tech237
Moderator
Username: Tech237
Post Number: 1159
Registered: 4-2004
| | Posted on Thursday, May 14, 2009 - 12:33 pm: |
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Keith - it is a trade off. More height gives you better line of sight capability and thus increasews your "local" contact range (usually more observable at higher frequencies).
Conversely certain heights (and usually measured in wavelengths or parts of) will lower the angle of radiation, which in turns helps in gaining long distance contacts. One wavelength (or around 36ft at CB frequencies) is usually pretty good for working those elusive DX stations.
Simon
Tech237
N7AUS
.
I thought he said, "there was no rust for the wicked, and I own an MGB"
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Airplane1
Senior Member
Username: Airplane1
Post Number: 1215
Registered: 5-2004
| | Posted on Friday, May 15, 2009 - 7:16 am: |
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Interresting Tech237, I knew 1 wave length 34ft at cb freq. as a starting point but I thought the higher the better from there. Wont the angle of radiation keep dropping as you keep going up even if not at every wave length?
AP |
Tech237
Moderator
Username: Tech237
Post Number: 1160
Registered: 4-2004
| | Posted on Friday, May 15, 2009 - 11:45 am: |
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Airplane - nope. You get to a point where your height above RF ground (may not be the same as physical ground) is such that the angle starts to increase again.
Every full wavelength the radiation angle will drop to as low as it will go, so going multiples of a wavelength doesn't really help any for DX (and that's what you're working on by dropping that angle), and you'll get extra loss from the longer run of coax. Again the extra height will increase you "local" contact range, which can be worked out by d= 1.415 x sqr root of height. I will admit that this is more noticable at VHF than CB, but does still have an effect on 27MHz.
Like most things in this game, antenna height is a trade off.
Simon
Tech237
N7AUS
.
I thought he said, "there was no rust for the wicked, and I own an MGB"
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 26
Registered: 4-2009
| | Posted on Friday, May 15, 2009 - 2:48 pm: |
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Tech237
Can you explain the math formula.
D = 1.415 x sqr root of height.
I done this problem at the 36' mark and d is 8.49
What does D stand for?????? |
Tech237
Moderator
Username: Tech237
Post Number: 1162
Registered: 4-2004
| | Posted on Friday, May 15, 2009 - 9:26 pm: |
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sorry d= is distance in miles to the radio horizon or line of sight.
If you do it for a mast of 18ft your line of sight distance is 6 miles, and for 72ft it becomes 12 miles. Not a great gain for doubling the antenna heightfrom 36ft.
Simon
Tech237
N7AUS
.
I thought he said, "there was no rust for the wicked, and I own an MGB"
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Flying_cloud
Junior Member
Username: Flying_cloud
Post Number: 27
Registered: 4-2009
| | Posted on Friday, May 15, 2009 - 10:14 pm: |
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thanks tech237
I did not know that I learn somthing every day lol! |
