Antenna's that get that VOODOO Audio thru the Ether!

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Antenna's that get that VOODOO Audio thru the Ether!

Post by Voodoo Guru » Thu Feb 24, 2005 10:42 pm

Well Ya'll,
If your gunna run Full Range Audio, You got to have the Signal for it.
It takes about a consistant 20db over S-9 signal to get all the Audio information into the Receiver without any ill-effects.
This takes a good amplifier with lots of headroom, and a good antenna.
We use several antennas, depending on the conditions and the distance that we're talkin.
Since these comparisons where done, we have taken down the NVIS Phased Arrays due to different problems. Storms, Strong RF Fields, etc.

Here are some results of the loop compared to the two other antennas.
The loop is now at a length of 1058 feet long, and a height of an average of 100 feet. We tried all different types and lengths of feed line and baluns. The final feed line and balun configuration was 450 ohm ladder line and a 4:1 balun at the tuner. we use this antenna on 160 - 10 meters.

The comparison antenna's are as follows:
1) 160 meter Carolina Windom used as a multibander thru a tuner. It is 268 feet long, and at a height of 100 feet. I use this antenna for 160 meters and for long distance contacts on 75 thru 10 meters due to its low angle of radiation.
2) 2ea, 20 meter 3 element Co-linear Phased arrays. These two antennas are seperated 68 feet from each other and phased together. They are at a height of 90 feet. This antenna is also a multibander used thru the tuner. We primarily use this array as a NVIS antenna for short range on 40 and 75 meters due to its very high angle of radiation on 40 and 75 meters.

We will describe how the antennas compare from band to band starting at 160 meters.
1) 160 Meters:
The loop does extremely well out past 200 miles due to its low angle of radiation. It is 2 wavelengths long at 1058 feet, this flattens the high lobes out alot flatter. This was the main reason we started with the loop long at 2000 feet. Because of tuning problems on the upper bands, we had to compromise and shorten the loop to its present length of 1058 feet.
The 160 meter Carolina Windom does better than the loop from 200 miles and closer.
The Co-linear is not operated on 160 meters.
2) 75 Meters:
The loop performs the best at long distance from 300 miles and longer.
The 160 meter Carolina Windom is also good from about 300 miles and past, but it is about 10db down from the loop.
The Co-linear is 10 to 20db stronger in signal than both the above antenna's at close range. This is from 300 miles and closer.
3) 40 Meters:
The loop performs the best at long distance from 400 miles and longer.
The 160 meter Carolina Windom is decent from about 300 miles and past, but it is about 15db down from the loop.
The Co-linear is 10 to 20db stronger in signal than both the above antenna's at close range. This is from 300 miles and closer.
4) 20 Meters:
The loop totaly out-performs the other 2 antenna's at long distance from 600 miles and longer by about 10 to 20db.
The 160 meter Carolina Windom performs well from about 500 miles and past, but it is about 10db down from the loop on the average.
The Co-linear performs fair on this band. This is the band it was desighned for. It has 6 high gain lobes which perform fair, but the Carolina windom and the loop beat it every time. We found out that this antenna has VERY high angles of radiation when used on 40 and 75 meters. That is the reason We built 2 of them and phased them together.
5) 17 Meters:
The loop totally out-performs the other 2 antenna's by about 10 to 20db, hands down.
The 160 meter Carolina Windom is decent, but it is about 10db down from the loop.
The Co-linear is a dog on this band and i don't use it.
6) 15 Meters:
The loop totally out-performs the other 2 antenna's by about 10 to 20db.
The 160 meter Carolina Windom is decent, but it is about 10db down from the loop.
The Co-linear is horrid on this band and we don't use it here iether.
7) 12 Meters:
The loop totally out-performs the other 2 antenna's by about 10 to 20db.
The 160 meter Carolina Windom is decent, but it is about 10db down from the loop.
The Co-linear is useless on this band.
8 ) 10 Meters:
The loop is incredible on this band! The angle of radiation is sooooo looooow, and the capture area is so great, that it will pick up signals that the other 2 antenna's will not even hear. The loop is at 37 wavelengths at 28.5Mc!! Another plus is that the SWR is not over 2.8 from 28Mc to 29.7Mc.
The 160 meter Carolina Windom is decent, but the loop is superior.
The Co-linear is useless on this band.
9) 6 Meters: (YES! 6 Meters)
The loop works exceptionally well on this band. The SWR is not over 2.5 from 50Mc to 54Mc.
The Carolina Windom is flat all the way thru this band and works terrific. No tuner needed.
The Co-linear is useless on this band.
10) 2 Meters:
I have tried the loop on 2 meters with decent local results, so it does radiate. The match is not bad, SWR of not more than 3.0 from 144Mc to 148 Mc.
The Carolina Windom radiates fair (especially off of the ends) on this band, and the match is good.
The Co-linear is useless on this band.

Well that is the performance of the antenna's here in the Swamps of Louisiana.
Last edited by Voodoo Guru on Fri Sep 18, 2009 2:59 pm, edited 2 times in total.
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Post by !KANT » Thu Mar 10, 2005 12:39 am

If you have the space and can get the antenna up high enough a loop can be the best thing you will use on the air--I know many who can attest to this, including myself. If I could get away with one here then I would put one up for 75 meters [545ft.].

Having an amplifier does provide headroom--see why some guys run 3 to 5Kw amplifers but only drive 'em easily to 1.5Kw without triggering the radio's/exciter's ALC circuit?? Stations with as little as S-6 signals can have readable/recognizable audio that sounds awesome [and you can still hear the sublties....it all depends on how quiet the band is].

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Bad News

Post by Voodoo Guru » Mon Mar 28, 2005 9:22 am

Well...got some bad news.

Looks like we are givin up the big acreage and movin to the Riverhouse for good.
No more room for the Huge loops anymore. That will be a shame. We have grown very accustomed to this loop on all bands.
It will be missed.

We will be replacing it with the following:

10 thru 20 meters = Tennadyne T-10 LPDA at 70 feet
40 and 75 meters = Colinear Phased Array (NVIS "close range" Antenna)
160 meters = Inverted L

All these antennas will be radiating against a Tunable Ground Radial System that we got the idea from N0KHQ.

Space is very limited, so we will enjoy playing with my "Yankee Antenna" (as Greg, W5UDX calls it 'cause It gets out to all the Yankees!) while we can.
Last edited by Voodoo Guru on Sat Mar 24, 2007 10:59 am, edited 1 time in total.
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Re: Bad News

Post by !KANT » Tue Apr 05, 2005 3:56 pm

wz5q wrote:Well...got some bad news.

Looks like we are givin up the big acreage and movin to the Riverhouse for good.
No more room for the Huge loops anymore.


Noooooo....say it ain't soooo..... :cry:


I still have to get something up for 160m....I just haven't been applying myself to alot of shyt lately.... :oops:

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Post by dg7lan » Thu Apr 07, 2005 12:39 am

fat stuff..

i still got my windom here. it´s ok but i´m looking for something different.. thought of a yagi but i think i will not bring it up high enough to get it in a flat angle. what about that loop stuff? i got a couple of trees on the left and the right side of my garden. but on the right hand side they belong to my neighbor and i only would ask him in emergency cases..i don´t like him.. maybe in the next step i will simply bring my windom a little higher off ground, it´s 10-15m now.. howmany ft is that.. *google* ahh..40-50ft. i can bring it up to 80ft in the max. do you guy think that will make a difference? do i get lower angle? how would such a loop be designed? and i would need a tuner, i don´t have one yet (cause i don´t need it on the windom, only for 160 but i use the internal)
as you see i don´t know much about antennas but i´m still learning.
hope to meet you ppl someday on 20/17/15m. have heard lot´s of ppl from the states in the last weeks.

73s,andy, ssbaudio.net
...if in doubt, increase bandwidth

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Post by !KANT » Fri Apr 08, 2005 3:16 pm

With most [if not all antennas] higher is better. Remember that on 75m and 160m getting antenna a halfwave [let alone a fullwave] length is near impossible for most people. I've heard some ops using loops as low as being placed on the ground and still get out quite well. Others have erected theirs up 10-40 ft. and get out like BOOM!! Just make sure you're feeding it with 450Ω ladder line or any minimal loss BALANCED feeder. You don't have an antenna tuner yet and you WILL need to incorporate one in your system to match it's feedline to 50Ω. **Type of tuner is usually dependant on amplifier output power.

And also remember, the higher you go in frequency the more gain you will attain from the antenna--Mike has a perfect example of that. :wink:

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Tricky Tricky

Post by Voodoo Guru » Fri Apr 08, 2005 7:27 pm

Loops are the preferred Antenna here.
In our experience Loops are Quieter due to the wire termination, they Receive better due to more capture area, they are simple and easy to work with, As you increase Frequency the radiation angle gets lower.
The bad things are that most people don't have the room to erect big loops. Nor due they have the supports to get them up in the air.
Loops are damn good antennas, they can be a little tricky.
There is allot of information on the internet about this. One of the best websites we have found is L. B. Cebik, W4RNL at http://www.cebik.com/radio.html
There is ALLOT of info here.
For loops:
http://www.cebik.com/fdim/atl1.html
and
http://www.cebik.com/wire/horloop.html
Basicaly, the higher in the air you put a loop, the lower the angle of radiation (better DX).

Too bad we will live again in a place that we cannot have loops.
They will be missed.
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Post by !KANT » Fri Apr 08, 2005 11:45 pm

Today I spoke to a friend of mine on 20m who is a long time advocate of Loop antennas--it's all he uses.....and he booms out like crazy. As we discussed my idea for a loop he immediately [mentally] calculated the length, pattern and gain of the antenna on other bands. Of course feeding it with ladder line is the best way to go for multiband performance.

Now, I do still have a concern about RFI to neighbors [since they're in close prox.]. When I lived in NYC I used ladder line to feed my loop and 40m Double Extended Zepp and the neighbors [or myself] had no interference. So maybe I'll be able to get away with it here.... :roll:

Loops are getting their just due. Some of the [audio] guys on 20m are noticing loops for their performance record--especially on the low-bands. Even talking about burying the feedline with successful performance.....let's see what happens.

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Loops are Kewl

Post by Voodoo Guru » Sat Apr 09, 2005 12:59 am

Yea, they work terriffic on the upper bands.
Almost too good sometimes.
How can that be??
Well.....you don't have the convenience of "beaming" your signal or nulling a received signal.
You receive from 360 degrees....all the time.
That can be a pain sometimes on a crowded band.
That is the only downfall we can really think of.

As far as Ladder Line causing RFI for your neighbors, We don't see that happening if you keep the line balanced. Keep it away from anything metal that would unbalance the line. It should work great.

Don't know about burying Ladder Line in PVC in the Ground. Have never done that.
We would think that it would cause the balanced line to unbalance due to being in such close proximity to Ground Potential.
The Rule is keep it away at least 6".
That would be interesting to find out for sure.
Last edited by Voodoo Guru on Sat Mar 24, 2007 11:03 am, edited 1 time in total.
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Post by !KANT » Sat Apr 09, 2005 6:34 pm

I think Marty [KA7GKN] has done it and has successful results--now others are trying it. George [K9TRQ]--this man knows his shyt about wire antennas....especially loops. He recommends twisting the ladder line as you go along.

As for me, I will have a great problem keeping it away from metal to feed it outside. And even then, I still have to try and keep it inconspicuous. The window panes open horizontally and the bugs are our worst enemy :evil: I'm feeding the fan-dipole with RG-8X through the window pane--drilled a hole in the aluminum siding, snaked it through and it runs along the court yard then up 40ft. to a branch [150ft. total length of coax]--had it buried but it was yanked right out the ground during one of our windstorms.

I can go the external balun way and have the 4:1 balun sit right outside the window and run 3ft. to 6ft. of coax. I remember the days of having RFI in the audio chain when I used ladder line [with a balun]. Until one day George told me to use the balun in the tuner instead of the external 4:1 balun.....and BAM!! RFI gone.

Now I know your using a 4:1 balun with 450Ω ladder line. I've asked others this following question and the answer was. "it doesn't make a difference". So here is my question.... Why not use a 9:1 balun instead of a 4:1 balun???--I'm sure cost could be a factor....though not a significant difference [like $30].

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Balun Jargon...

Post by Voodoo Guru » Sat Apr 09, 2005 8:08 pm

When it comes to baluns....We only use DX Engineering Current Baluns.
Reason being?
We've blown too many of the others up... And we mean "BLOWN UP"!
They have to be heavy duty if used after a Tuner, feeding 450 ohm ladder line, feeding a loop. In this type of application, when working away from the natural resonance of the antenna, the SWR is Very High.
Even though you might have the tuner "Tuned" to a 1:1 SWR, everything after it towards the antenna is still at that original SWR.
This in turn places an ENORMOUS amount of Voltage and/or Current on the Balun. The next thing you know, the Ferrite is saturated, the Teflon insulation melts, the balun windings short, and then the ferrite Explodes.

Image

We haven't blown up the 10KW DX Engineering Balun as of yet.

Image

You would think that using a 9:1 balun would the correct thing to do. But the choice is really dependent on the actual impedance that is on the line and/or the impedance of the antenna.

We could go on and on, but this is all stuff that can be accessed on the web. Some of the best information we've come across is on the DX Engineering Website.

http://www.dxengineering.com/ProductDet ... 0&DeptID=9

Wish we could put pictures on here to show it too you.

Ha HA!! Figured it out!
Last edited by Voodoo Guru on Sat Mar 24, 2007 11:04 am, edited 2 times in total.
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Post by !KANT » Tue Apr 12, 2005 7:43 pm

I've looked at DX Engineering before. In fact they are the first manufacture of baluns that I saw 6:1, 9:1 and 12:1 baluns offered. I've also looked at RadioWorks baluns too. Back in NYC I used a Van Gordon 4:1 balun for the loop and 40M D.E.Z.. It worked great and no problems at all....then again I never exceeded 1KW.

At this point I doubt I'll be putting anything more than 1.2KW in an antenna. Still doesn't negate the fact I should highly consider the DX Engineering baluns....--you get what you pay for.... :wink:

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Smoke

Post by Voodoo Guru » Wed Apr 13, 2005 8:27 am

The burnt up Balun above was the biggest Radio Works balun they make.
The advertised power rating is only good at a 1:1 SWR and is not continuous "Brick on the Key", it is SSB.
When used after the tuner in an application like ours, it'll smooooooke!
we blew 2 of Radio Works Baluns up.
One was our fault, we were runnin legal limit on 10 meters FM.
The second Balun, we were runnin legal limit on SSB on 20 meters.
It should have survived.

The DX Engineering Balun just gets slightly warm.
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Post by !KANT » Wed Apr 13, 2005 12:01 pm

That's good info to have. I've always looked at the RadioWorks baluns and read their publications on balun theory [and of course checked their products]. The DXE look strong--duh, metal not PVC--and should be enough to give 'em a chance. I'll look into it some more. Besides, there many be better/higher power transfer to the antenna than "weaker" baluns.

At this point I'm still comtemplating a way to run the L-line to the antenna. Once that's accomplished then I'll get to the next step. It's recommended not to allow the ladderline to lay flat on the ground--when it rains, 16ft. down the line it will become very unbalanced and create arcing. One of the possible ways to go about this will be along the outside of the complex wall, to our patio, then to the feedpoint in the trees....just have to twist the line all the way through the entire run... :shock: --so much for remaining inconspicuous :? . That's only one idea...still thinking of others.

BTW, the results for the ops that buried their L-line are in, and they are successful and promising. They've been using their loops with no problems or signs of difficulty tuning, arcing or causing RFI. So it can be buried in PVC and provide very good results.

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Post by dg7lan » Thu Apr 14, 2005 12:13 am

...wish I would have enough power to burn my balun. and it´s a really small one :roll:
...if in doubt, increase bandwidth

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Post by !KANT » Thu Apr 14, 2005 10:58 am

:shock:

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