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What determines Wattage handling
- Thread starter Heavy Metal
- Start date
What type of antenna are you asking about on band width.
I built a vertical and had my then 14 year old son assisting me.
I thought I had it tuned great when my son told me it does not matter what frequency he puts the mfj analyzer on it always reads around 1.1:1 VSWR.
I thought to my self wow the perfect antenna resonant every where. Then I thought I might need to go see how my son was actually using the analyzer.
Found out that my son had connected the antenna switch to analyzer and had the switch set to the dummy load position.
The dummy load has GREAT band width but the efficiency is rather poor.
The higher the Q of the antenna usually means less bandwidth.
Keep in mind most antennas only have the maximum gain at design frequency and loose gain as the frequency of the transmitter is moved away from design frequency.
So back again to exactly what type of antenna are you asking about?
I built a vertical and had my then 14 year old son assisting me.
I thought I had it tuned great when my son told me it does not matter what frequency he puts the mfj analyzer on it always reads around 1.1:1 VSWR.
I thought to my self wow the perfect antenna resonant every where. Then I thought I might need to go see how my son was actually using the analyzer.
Found out that my son had connected the antenna switch to analyzer and had the switch set to the dummy load position.
The dummy load has GREAT band width but the efficiency is rather poor.
The higher the Q of the antenna usually means less bandwidth.
Keep in mind most antennas only have the maximum gain at design frequency and loose gain as the frequency of the transmitter is moved away from design frequency.
So back again to exactly what type of antenna are you asking about?
Really theory in general vertical dipole like iMac 2000 but more so like I10 simple straight no coil rod and possible ground plain.
Kiss antenna lol
Kiss antenna lol
The I2K is very broad banded, I use one myself,
the reason it is so broad banded is the matching network that is used to match it.
DB ( who has a vast knowledge of antenna theory) will say that the I2K does not really perform due to it's poor matching network.
I2K works well on 10/11/12/and 15 meters no antenna coupler required.
I like that antenna for cost vs frequency covered.
I have put legal limit into the I2K and have had no problems with it,
As far as a balun, look at a palsy match ( spelling may be wrong) it uses coax for making a balun so the power handling capability will be limited to the transmission line.
https://www.arrl.org/files/file/Technology/tis/info/pdf/9811054.pdf
good article to read
the reason it is so broad banded is the matching network that is used to match it.
DB ( who has a vast knowledge of antenna theory) will say that the I2K does not really perform due to it's poor matching network.
I2K works well on 10/11/12/and 15 meters no antenna coupler required.
I like that antenna for cost vs frequency covered.
I have put legal limit into the I2K and have had no problems with it,
As far as a balun, look at a palsy match ( spelling may be wrong) it uses coax for making a balun so the power handling capability will be limited to the transmission line.
https://www.arrl.org/files/file/Technology/tis/info/pdf/9811054.pdf
good article to read
vertical 1/4 wl
1/4 wl radiator and four ground radials bent down at a 30 to 45 degree angle to present a 50 ohm impedance match.
direct feed no matching network required,
Use an RF choke or line isolator, ferrite beads over the coax or whatever your choice is for preventing tvi rfi .
Marconi has does some modeling and posted his results on the 1/4 wl ground plane.
The starduster is about as close to a balanced vertical you can get commercially for sale. that little ground plane works great.
1/4 wl radiator and four ground radials bent down at a 30 to 45 degree angle to present a 50 ohm impedance match.
direct feed no matching network required,
Use an RF choke or line isolator, ferrite beads over the coax or whatever your choice is for preventing tvi rfi .
Marconi has does some modeling and posted his results on the 1/4 wl ground plane.
The starduster is about as close to a balanced vertical you can get commercially for sale. that little ground plane works great.
I was thinking more radical like .64 see if straight run no chiling nada just straight up and 4 ground radials and that's another thing what is rule or thumb on ground radials 1/4 wave of vertical say 45.150' rounded up, center freq 14.175 MHz and the radials be 16.5' rounder a bit down is this about correct using 640 / 14.175 and 234 / 14.175. And finally as above degree 45 or straight out which is more effective I believe if not mistaken 45 degrees since basically throw it best up and out rather that just up.
Why the big hang up on .64 wave? It still needs a matching network in the base and on HF it will be ridiculously tall. A simple 1/4 wave groundplane will be just as effective and MUCH easier to construct. I know of nobody that uses a .64 vertical on HF.......nobody.
AS CK said, the .64 is an 11 meter hang up thing.
The .64 does work but not enough gain over a 1/4 wl vert to be seen by the receiver on the other end.
The 45 degree angle on the 1/4 wl is just like an inverted v type antenna, bringing the ground elements down towards earth ground increases the impedance at the feed point.
If you are looking for DX on 20 hard to beat a dipole, or for that matter even a half square or bob tail curtain.
Many better options than the 1/4 wl vert, heck even a delta loop or full wave loop will beat a 1/4 wl vert
The .64 does work but not enough gain over a 1/4 wl vert to be seen by the receiver on the other end.
The 45 degree angle on the 1/4 wl is just like an inverted v type antenna, bringing the ground elements down towards earth ground increases the impedance at the feed point.
If you are looking for DX on 20 hard to beat a dipole, or for that matter even a half square or bob tail curtain.
Many better options than the 1/4 wl vert, heck even a delta loop or full wave loop will beat a 1/4 wl vert
You can't. Once you get towards a 1/2 wave then the antenna becomes voltage fed instead of being current fed and presents a high impedance - it gets seen as a high value resistor. So to get it to work with a CB it has to have a matching circuit. It is unavoidable. Once you get to 3/2 wavelengths, because its an odd harmonic it becomes current fed again however for a vertical antenna, once you get towards a wavelength long then most of the power is sent up towards the sky so not good for DX or local.
You cannot run a 5/8 (.625) or a .64 wavelength antenna without some form of matching, unless you want a high amp/radio killing SWR. All 5/8 wavelength antennas (including the .64 wavelength antennas) have some form of matching. It is not a self resonant length, nor is it a length that provides a naturally low SWR.
If you want direct feed, look at 1/4 wavelength groundplane antennas. When it comes to verticals those are pretty much your options if you insist on being able to direct feed. Perhaps a center fed dipole could be made to work as a direct fed vertical as well (thinking T2LT type antenna).
I still want to know how much power you are planning on running as you haven't answered that question yet. That knowledge can make all the difference. That being said, if you are planning on running so much power that you need a direct fed antenna system to be able to handle it, the question very quickly becomes why?
The DB
If you want direct feed, look at 1/4 wavelength groundplane antennas. When it comes to verticals those are pretty much your options if you insist on being able to direct feed. Perhaps a center fed dipole could be made to work as a direct fed vertical as well (thinking T2LT type antenna).
I still want to know how much power you are planning on running as you haven't answered that question yet. That knowledge can make all the difference. That being said, if you are planning on running so much power that you need a direct fed antenna system to be able to handle it, the question very quickly becomes why?
The DB
Really now, like even 1/4 down to what would be befpre really sticking up a horizontal wire?
Not obsession on .64. Full wave on 10m @.64 on 11m - @5/8 on 12m @1/2 on 20m comes awfully close to 1/4 wave at 40m is not mistaken, Or I off real bad on calcs?
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Yes your way off.almost 1/2 wave at 15m not 20. not even close to 1/4 at 40 .Anyway end fed vertical 1/4 waves dont work well. unless you have a good ground radial system Also the matching network designed for about 200 ohms of a 5/8 it is only going to make the match worse at 1/4 wave . Yes you can use a tuner and make your radio happy .But at 40 m the 2k is little more than a dummy load.Not much better on 20 but does work fairly well on 15 although it shouldn't due to the mismatch (end fed halfwave impedance is over a thousand ohms) must be some huge losses in that matching network.
Heavy metal.
What EXACTLY is it you are trying to accomplish? Or learn?
Thread is about power handling but the discussion has went way of topic and is now about antennas. ( One of my favorite parts of the hobby).
So what are you wanting to do? Have an antenna with unlimited power handling capabilities, Broad banded with gain on all bands you want to work?
Lots of members here with vast knowledge and they will gladly assist in whatever you are trying to do within reason.
Just really need to know what it is you are trying to achieve.
What EXACTLY is it you are trying to accomplish? Or learn?
Thread is about power handling but the discussion has went way of topic and is now about antennas. ( One of my favorite parts of the hobby).
So what are you wanting to do? Have an antenna with unlimited power handling capabilities, Broad banded with gain on all bands you want to work?
Lots of members here with vast knowledge and they will gladly assist in whatever you are trying to do within reason.
Just really need to know what it is you are trying to achieve.
How low can one go without having radials( not enough area) on a vertical before having to use a wire horizontally. And then going to have to use a shortened one or wrap it around yard. But want to keep it all on I directional.
I ran the numbers and this is the result. All lengths are approximate and are at the centre of the bands except 10m which is at 28.5 MHz.All but the 1/4 wave radiator will require a matching network at the feedpoint which can only be tuned to one band at a time.
ALL vertical radiators will benefit from radials despite the assertion by some that the 1/2 wave does not. The 1/2 wave is not subject to as much ground losses but it does benefit from a decent ground plane.
1/4 wave 1/2 wave 5/8 wave
10m 8'2" 16'4" 20'6"
12m 9'5” 18'4” 23'6”
15m 11' 22' 27'6”
17m 12'11” 25'10” 32'4”
20m 16'6” 33' 41'4”
40m 33' 66' 82'6”
80m 66' 132' 165'