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Stacked M103C vs 5 element/7 element
- Thread starter distortion
- Start date
2 S units over the I-10K? An S unit should be 6db, but since no CB or for that fact Amateur rig has a linear calibrated receive meter it is more like 3db per S unit so you are seeing about 6db gain over your ground plane.
Take into account that now you need a rotor, you need to spend your time, or pay someone else for their time to install this yagi. The cost of the yagi.
Everything totaled how much did it cost in $$$ per db gain to achieve a 6db increase? 1 S unit on a calibrated meter.
I agree yagi's are the way to go for gain, for 20 meters and up the first 10DB of gain is from the antenna, but gain gets expensive quick.
The big guns use stacked yagi's. But not in the way they are stacked on 11 meters, They stack them at 50 feet and at 100 feet, height depends on frequency etc. etc.
You may want to hold onto that I 10K, put it at 50 feet and your yagi at 80 or 100 feet, there will be times and conditions when that I 10K will outperform that yagi depending on the distance to the recieve station.
Take into account that now you need a rotor, you need to spend your time, or pay someone else for their time to install this yagi. The cost of the yagi.
Everything totaled how much did it cost in $$$ per db gain to achieve a 6db increase? 1 S unit on a calibrated meter.
I agree yagi's are the way to go for gain, for 20 meters and up the first 10DB of gain is from the antenna, but gain gets expensive quick.
The big guns use stacked yagi's. But not in the way they are stacked on 11 meters, They stack them at 50 feet and at 100 feet, height depends on frequency etc. etc.
You may want to hold onto that I 10K, put it at 50 feet and your yagi at 80 or 100 feet, there will be times and conditions when that I 10K will outperform that yagi depending on the distance to the recieve station.
6db does sound about correct. That is probably an accurate figure considering the landscape and nearly a wavelength in lost elevation. I am fully aware of the shortcomings of cb meters. This is a very good point.
I feel like it was worth it though. In the shootout situation, I was able to gain the equivalent of thousands of dollars in amplifier for probably $500 or less bracketed to the house and installed, I bought everything used on qth.com.
I'm now running a 3 element @ 85 ft temporarily, w/ a set of laser 400's going up. I've determined height is might. Everytime I raise it up another 10-20 ft, I feel like I've entered a whole new world. I hear stations so much further out on the beam @ 85 ft than the i10k every did. A lot of that has to do with the landscaping around me, and the 35 ft. hill in front of me
I guess if I ever upgrade from laser 400's, I will have to stack them, but I do not foresee getting too much larger, as stacking a set of 6's, 7's, 8's just doesn't seem worth the 3db gain.
I've talked to a few people with nice beams over 100 miles away barefoot. I can't say I could ever wish for too much more than that
Josh
QTH is a great place to find stuff for homebrew, I homebrewed my 4-1000A amp from parts purchased of QTH.com
Check out this link it will show you what the gain is for the amount of elements on a yagi, DBD gain not DBI.
The Ultimate Guide to 11 Meter CB Antennas
I have compared 4 element yagi to a 2 element quad, the recieve station could not hear the difference or see any S meter change when I switched from the 4 element yagi to the 2 element quad.
The yagi was at 72 feet and the quad was at 45 feet, quads will give a lower angle of radiation at a lesser height.
Antennas are fun to play with and build, I am sure you will enjoy yours when you get it up in the air.
for shoot outs, have the guys go radio to radio no amps, then one can truly tell who has the better antenna system, the best transmitter in the world is only as good as the antenna it is transmitting on.
Check out this link it will show you what the gain is for the amount of elements on a yagi, DBD gain not DBI.
The Ultimate Guide to 11 Meter CB Antennas
I have compared 4 element yagi to a 2 element quad, the recieve station could not hear the difference or see any S meter change when I switched from the 4 element yagi to the 2 element quad.
The yagi was at 72 feet and the quad was at 45 feet, quads will give a lower angle of radiation at a lesser height.
Antennas are fun to play with and build, I am sure you will enjoy yours when you get it up in the air.
for shoot outs, have the guys go radio to radio no amps, then one can truly tell who has the better antenna system, the best transmitter in the world is only as good as the antenna it is transmitting on.
As mentioned in the previous post:
"Check out this link it will show you what the gain is for the amount of elements on a yagi, DBD gain not DBI."
Im afraid i disagree with you..it seems to me as:
1- The gain given would be closer to the truth in dBI rather than dBD.
2- But most importantly, I wouldnt take that diagram too seriously as gain is NOT primairily depending on number of elements but it is for the most boomlength that makes the difference.
....the only figure that comes close to the described gain would be the 2el yagi
The 2el is capable of producing 6..7 dBI depending on how it is setup
(for gain or for front to back).
There is no way the "typical" difference between a 4el and a 8 elements is only 0,4dBI
Etc...etc...No..i wouldnt recommend to use that diagram to anyone.
Any antenna book would give you another opinion.
Strange cause normally i really appriciate that website...
About your remark about the lower toa of the quad...Sorry to say, but i disagree with that too.
That is from the old days..if one measured the different TOA from quads
(as can be done with R&S systems or calculate through modeling programms)
The beamwidth of the quad is often sligthly broader than a yagi this is logical as the antenna aperature is bigger..but that is not..and i repeat again not noticable....
TOA is highly dependable on polarisation/heigth/ground conductivity etc...not the difference between a quad and yagi.
Ofcourse i appriciate any other point of view!
Kind regards,
Henry
"Check out this link it will show you what the gain is for the amount of elements on a yagi, DBD gain not DBI."
Im afraid i disagree with you..it seems to me as:
1- The gain given would be closer to the truth in dBI rather than dBD.
2- But most importantly, I wouldnt take that diagram too seriously as gain is NOT primairily depending on number of elements but it is for the most boomlength that makes the difference.
....the only figure that comes close to the described gain would be the 2el yagi
The 2el is capable of producing 6..7 dBI depending on how it is setup
(for gain or for front to back).
There is no way the "typical" difference between a 4el and a 8 elements is only 0,4dBI
Etc...etc...No..i wouldnt recommend to use that diagram to anyone.
Any antenna book would give you another opinion.
Strange cause normally i really appriciate that website...
About your remark about the lower toa of the quad...Sorry to say, but i disagree with that too.
That is from the old days..if one measured the different TOA from quads
(as can be done with R&S systems or calculate through modeling programms)
The beamwidth of the quad is often sligthly broader than a yagi this is logical as the antenna aperature is bigger..but that is not..and i repeat again not noticable....
TOA is highly dependable on polarisation/heigth/ground conductivity etc...not the difference between a quad and yagi.
Ofcourse i appriciate any other point of view!
Kind regards,
Henry
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If your goal is to get more gain then a 4 element yagi can provide on this band, there are two options I can think of. Stacking a pair of smaller beams will give more gain then adding more elements beyond the four in most cases. This is not easy to do correctly because of the mechanical requirements and the need to have as close to one wavelength separation between the two antenna as possible.
When two beams are stacked closer then one wavelength the individual patterns almost completely overlap and do not gain the full benefit of two antennas. If the spacing is brought below 1/2 wavelength most of the gain is lost. Stacking beams provides more gain without a significantly "tighter" pattern like adding more directors would.
If stacked beams are spaced reasonable over the 1/2 wave point, both antennas are correctly tuned and driven trough the proper phasing harness, the gain could be as high as 3 db over a single antenna. Make a mistake and you could lose most of it. You'll need a fairly big rotor to turn a pair of 11 meters beams with the torque that the stacking boom will present.
The next option is consider using a quad or quagi style beam. The important thing is that the beam has a quad driven element. This has been shown to provide a 2 db increase over a yagi style beam with the same elements. Recent studies suggest this may only be true when comparing antennas with less then about 5 elements. When going beyond 4 elements, each extra element adds less gain to the antenna then the first 4. It appears that with the quad even less gain is added beyond 4.
This may give the quagi which uses a quad driven element and reflector with yagi director elements some advantage. During the 1970's CB boom we had two locals that used impressive beam setups. One had a Laser 400 and the other had stacked PDL-II's on a 24 foot stacking boom. Both were in the same town with the same power and height. The stacked PDL-II's almost always beat the guy with the 400 in the distance.
This is not the best comparison because the stations were a few miles apart and that could cause all types of unexpected variables. Point is those stacked two element quads were excellent performers. Knowing what I do today I question how the gain would have increased if we added one set of horizontal and vertical yagi directors to each antenna. Then what would happen to DX contacts if the system were run circularly polarized?
When two beams are stacked closer then one wavelength the individual patterns almost completely overlap and do not gain the full benefit of two antennas. If the spacing is brought below 1/2 wavelength most of the gain is lost. Stacking beams provides more gain without a significantly "tighter" pattern like adding more directors would.
If stacked beams are spaced reasonable over the 1/2 wave point, both antennas are correctly tuned and driven trough the proper phasing harness, the gain could be as high as 3 db over a single antenna. Make a mistake and you could lose most of it. You'll need a fairly big rotor to turn a pair of 11 meters beams with the torque that the stacking boom will present.
The next option is consider using a quad or quagi style beam. The important thing is that the beam has a quad driven element. This has been shown to provide a 2 db increase over a yagi style beam with the same elements. Recent studies suggest this may only be true when comparing antennas with less then about 5 elements. When going beyond 4 elements, each extra element adds less gain to the antenna then the first 4. It appears that with the quad even less gain is added beyond 4.
This may give the quagi which uses a quad driven element and reflector with yagi director elements some advantage. During the 1970's CB boom we had two locals that used impressive beam setups. One had a Laser 400 and the other had stacked PDL-II's on a 24 foot stacking boom. Both were in the same town with the same power and height. The stacked PDL-II's almost always beat the guy with the 400 in the distance.
This is not the best comparison because the stations were a few miles apart and that could cause all types of unexpected variables. Point is those stacked two element quads were excellent performers. Knowing what I do today I question how the gain would have increased if we added one set of horizontal and vertical yagi directors to each antenna. Then what would happen to DX contacts if the system were run circularly polarized?