The AM Forum

got up early this morning hoping for surf at the beach but storm missed us. Flipped on 40 meter CW and JAs were coming in. Flipped between the KAZ and 160 foot beverage. KAZ wins again. Both face west and the KAZ had less noise and better copy.
Last night I had WBZ 1030 on (east). The Beverage off the back was about 30 dB stronger than the KAZ. KAZ has a great null. NY AM stations to the West are a bit stronger on the beverage.
WWV KAZ wins most of the time WWVH KAZ wins.

Still playing with simulations for 2 or 3 phased KAZ. In line configuration looks the best. 2 or 3 would fit in the same space as a short beverage but I think they will perform better than a short beverage.
I need to revisit the K9AY simulation but first look didn't perform that well on 40.
Another option a ground mounted rotor to rotate a KAZ for variable null position

What is a KAZ antenna?

    Yeah, what Don said, inquiring minds would like to know...

look it up on line. A loaded delta loop. mine is 30 foot long base 20 foot height
mounted 5 feet above ground. load is a 1K resistor matched with a 4:1 turns ratio BB transformer to coax. I'm shooting for 160 through 40 meter low noise RX ant. It really has a deep null off the back. Phased pair is even better.

It's a terminated loop. It's in the same family as the EWE, Flag, Penant and K9AY. All of these terminated loops produce a cardioid pattern with a broad forward lobe and fairly deep but narrow null off the back. The position of the null off the back can be varied by changing the shape of the loop.

The KAZ is much longer than it is tall. This shape produces a null a very low elevation angle. A null at a low elevation angle is preferred for broadcast band/MW DXing, but is not usually the best for amateur radio/SW/HF use. Generally speaking, a broad front lobe is not the best for amateur radio use too.

maybe the 2:1 ratio I'm using isn't quite a KAZ but was surprised it out performed a short beverage into JA land and at WWVH. The short beverage does play better on the broadcast band.

That's weird. I would expect it to be the other way around.

How long is the Beverage? How high. How is it fed?

The beverage is about 160 feet long #22 teflon wire through branches. I think there is one spot in the middle up close to 20 feet but mostly under 15 feet.
Load is 1K into a copper pipe almost into the water table. Feed is 4:1 transformer. same design as the KAZ transformer. Coax to the RX.
I am also very surprised but have listened to WWVH a number of times and then yesterday on 40 CW the JA was clearly a better copy on the KAZ. The Beverage had a lot more noise.
A whole different story on the broadcast band where the beverage wins. But off the back the KAZ null almost takes WBZ out and the beverage off the back was about 10 dB stronger. I measured about 30 dB null attenuation with a step attenuator.
160 feet is about as long as I can do without dropping into the stream bed so this is my reference antenna. A pair of beverages would be limited to about 120 feet each. the loop is nice and small so could easily phase a pair of them East and another pair west. I need to revisit the K9AY maybe a bit smaller in loop size.
Simulation didn't look all that great but I didn't have the load grounded.
I got my ideas from Dallas Lankford articles and scaled smaller.

Your Beverage is probably a little high. Anything from on the ground to about 7 feet is where you want it. This will likely increase the directivity and reduce the sidelobes. The lower you go, the lower the takeoff angle also. The termination Z seems high too. Something in the 400-600 Ohm range would be better.

BTW, a pair of end-fire phased 120 footers would give you a pretty nice pattern on 40 meters. I bet the font lobe is not anywhere near as narrow on your Kaz. Also compare the high-angle response to your Kaz.

Add a second set about 85 feet away in broadside and you would be hearing like JJ!

Hi Frank,

Is the loop termination in series with the loop itself, or does it run from the end corner of the loop to ground?  How do you determine the size of the term R and the matching xfmr ratio?  It seems like that small loop might be a good way to go.  I have played with short beverage antennas here with somewhat poor results.  I had a 450-500' beverage just laying on the ground out thru the woods.  Used it terminated and unterminated with not so great results.  I think, however, I might be getting re-radiated noise/interference from my tower which is close by...don't know, but need something quieter for 40 thru 160M receiving.

73,  Jack, W9GT

The KAZ was developed for MW DXing as a pennant ant. optimized for MW.

John Bryant, big time MW DX guy & now a SK, did a lot of work with these & developed the super kaz (more gain) as well.

Neil Kazaross developed the first one hence the name.

Termination is in series with the loop. Steve you might be right on the height.
I did try 500 ohms on both antennas and didn't notice much change so removed the low value. I'm not set up for variable load and not likely to get a family member to stand outside turning a pot for hours to zero it in.  MW the beverage always wins so it could be the height thing. I have never seen the beverage win for WWVH.

OK on term.  What about the matching xfmr?  What is procedure for determining what you need?

73,  Jack, W9GT

I just took a 1/2 inch type 43 core and wound 4 turns of #26 teflon for the primary and 16 turns for the secondary. swag

Very interesting experiments Frank. I'm enjoying the thread. My two loops are now about 20 feet at the apex, and more than 30 feet across the bottom. They are both fed with a 9:1 transformer (30T primary, 10T secondary) and between 200 and 300 feet of RG-6. Neither of the loops is equipped with a preamp. Sometimes I run them unterminated for a bi-directional pattern, and other times I terminate them with 470 ohm resistors so one favors the south, and the other the east. I'm always surprised at how much signal they can gather from the BCB to 40 meters, and how much quieter they are compared to my 256 foot transmitting antenna. While listening to a couple of guys chatting on 75 meter sideband, I shot the video at the link below to show how well a weak signal jumps out of the background noise. Watch the noise on the baseline of the spectrum scope at the 30 second mark when one of the stations has dropped power temporarily. He is pretty much swallowed up by band noise when the 256 foot center-fed transmitting antenna is switched in.

http://www.youtube.com/watch?v=4rqgzVqqdAo

I have found them to be very directional from the AM broadcast band through 75 meters, but not so much so on 40 meters. I would imagine you would see much more directional behavior with a phased array of these, as in your simulation.

Rob W1AEX

Good article on this here:
http://home.comcast.net/~markwa1ion/exaol2/z_transformers.pdf

Great info!  Thanks very much!

73,  Jack, W9GT

Make a 120' Beverage from 5 brass Slinky's, termination will be in the 1200 Ohm area.

Rob,
Cut them a little smaller if you want to improve the performance on 40 meters. I started with them larger and found the same problem on 40 and WWV at 10 MHz. The loops are much more quiet then the 160 foot beverage but I may need to reduce the height. I hope to give that a try this weekend. 

Well HUZ I just did some short beverage simulation at 6 feet high 120 feet long and performance pretty much sucks. Then I did a pair of them spaced 80 feet apart and performance again sucks at that short length.  My yard layout doesn't allow more than about 40 feet stagger which is I bet too small.
My simulation came with a pennant simulation which also looks interesting.
So it looks to me that if you don't live near Tom Vu. State forest the loaded loop offers better performance.

Yup, good idea. I wound a transformer and have everything else ready to install a smaller one that will be aimed towards Europe for some 40 meter listening this fall. Probably get around to installing it sometime next month.

Keep up the good work!

Man what a crappy night for sleeping.
Rob,
my side property lines goes east-west so playing with phasing a pair of them in line.
My KAZ didn't work on 40 until the base got down to 30 feet. I'm sure you can go smaller but simulation showed 160 losses were taking off so stayed at 30 feet.
I just don't measure or simulate much Front to back with a short beverage. Then the coax run has to go out into the woods in my case to hit EU.

Take a look at the patterns I posted below. Those are two, 120-foot long Beverages, spaced 20 feet and offset 25 feet. That pattern will beat any terminated loop.

Eighty-feet of spacing is just about 0.625 wavelength spacing on 40 meters - perfect. Even a half-wavelength (65 feet) would be FB.

well the wind stretched the beverage a bit so it was hanging lower this weekend. I did notice a couple times the beverage had better signals than the KAZ, but the KAZ has such a nice null off the back. I think I will put both up here up north and run them a while. I think the beverage had stronger signals on 80m.

Steve, if I put up two beverages spaced about 80 feet apart, what is the smallest stagger I can run on them. I think I can get about 25 feet since the north property line is a lot longer (215 ft). It does drop off into the stream bed though.

Screw the WX man we didn't get the storm because I invested in a nice Andersen storm door.

Mine have an offset of 25 feet and are spaced 20 feet. They work FB.

A parallelogram would be simpler - no ground rods and only one termination and matching transformer.

So you don't use any phase delay between them? I wonder what is the point of staggered layout? Lankford uses a delay based on angle of signal and distance between antennas.

Yes, there is phase delay between them. The amount of spacing and the amount of phase delay determines the directional pattern - just like phased verticals, dipoles or any other element.

The amount of phase delay varies with frequency. But so does the spacing with respect to wavelenth, so the delay tracks over frequency for several bands (depends on the spacing/offset between the elements).

I've been playing with a pair of 120 foot beverages and the simulation likes about 48 foot stagger and 48 foot spacing with 120 degrees delay. I let simulation select stagger and spacing after I found 120 degrees worked good. I wish I could do phase delay as a variable with 4NEC2.
I think even the cat would be ticked with me if that was in the back yard.
180 degrees didn't look that good for me. Parallelogram would not fit well in my back yard.
I'm starting to think a KAZ on one side and beverage on the other both facing East and do some more testing. This past weekend beverage seemed better on 75.

simulation error DA forget what i said

Not that I have verified the HUZ phased beverages I went back to the loops.
I have simulated 3 loops phased taller than the KAZ configuration with very impressive F/B numbers. I have them for 40 and 80 meters and yet to do 160. The 80 meter version works ok on 40. They are close spaced with around 80 degree phase shift between them. The kicker is the F/B is over 40 dB at 40 degrees elevation. The simulation had to run a while to get there but the pattern is quite pretty. the null off the back is about 180 degrees wide.
Loss are higher than the beverages though

The phased Flag antenna looks like it will play over 3 bands and has the advantage of lower height.The KAZ on the third band usually ended up quite high angle. Also simulated Dallas Lankford's L/C delay line and found the delay unstable over a wide frequency range. So it will take a different length of coax on each band or a multiple section delay line to be BB. As the frequency approaches Fc of the delay line the delay time takes off. Multiple sections of small delays shift Fc higher. My old fiberglass poles from the Quad could get a new life.

Flag numbers All bases 1/2 meter above ground All numbers in meters
All matched to 600 ohms feed (not critical)

160m  2.9M high, 9.5M wide, 970 ohms
80M    3.1M high, 7.2M wide, 985 ohms
40M    2.4M high, 4.4M wide, 965 ohms

Shot for 30 degrees angle and let 4nec2 select everything
3 band ant was close to 80 meter size. angle comes up to 45 degrees on 40 but only down about 2 dB at 30 degrees. Spacing 20 meters

I set up the simulation to select KAZ sizes. all bases 1 meter off the ground. again everything in meters. Again the 80 meter size looks good 160 through 40 meters with more loss on 160. Again simulated for best performance F/B at 30 degrees. Interesting how 4nec2 selected similar sizes for 80M and 40M and was so close to the KAZ I put up at gfz so.

160m= 5.7M high, 18.3M wide, 932 ohms
80m = 3.2m high,  8.9M wide, 860 ohms
40m = 3.7M high, 8.5M wide, 883 ohms.

Next compare Flag and KAZ performance phased. I started with selecting a phase delay and let the program decide best spacing. 2 phased produces a nice wide null off the back.