Switchable Direction EWE Antenna

[W8EJO]

The "Super Kaz" is the way to go for receiving antennas for those who don't have the acreage for a Beverage.

http://www.dxing.info/equipment/kaz_bryant.dx

[Steve - WB3HUZ]

The Kaz might be good for MF but no better than any other terminated loop (K9AY, EWE, pennant, etc) for HF use. They all have the same RDF. The various configurations just move the null around on the back side. For BCL stuff, it would probably be best to put the null at or near zero degrees elevation. But that angle is about useless of the ham scene, since nearly all noise and QRM will be coming in from much higher angles. The K9AY was specifically designed to have the null around 30 degrees.

Read the intro of the review

"I was really excited when veteran MW DXer Neil Kazaross began using the EZNEC antenna modeling software to optimize various large loop antennas for MW DX use."

[WA1GFZ]

My yard is set up so it would be easy to mount a pair of EWE or super KAZ antennas side by side almost 100 feet apart favoring East or West. The question is would a k9ay work better?

[Steve - WB3HUZ]

Better for what? They're all terminated loops. All the different shapes do is change the elevation of the null on the back side and the bandwidth of the antenna system. That's it. All of them have an RDF of about 7 and a DMF of about 11. A vertical has an RDF of 4.  A properly terminated one-wavelength Beverage has an RDF of about 10 and a DMF of 19.

[WA1GFZ]

Pulling signals out of the noise. A east facing bev. would not work for me because my house is on the east end of my property. I have the perfect spot for a K9AY but I suffer from wire antenna disease where bigger is better. So to save time I wonder what is the best way to go. I was even considering mounting a rotor near the ground and building something that could be rotated. I have 2 35 foot trees on each side of my property that would be perfect supports for a pair of super kaz antennas. The feed points would be within 50 feet of the house.
 

[Steve - WB3HUZ]

Bigger is better isn't always required for receiving antennas. You can make up lost gain with a preamp, if needed. Try to place whatever you put up as far from your transmitting antenna and your house as possible. You don't want reradiated noise from your TX antenna to get into your RX antenna. Same for any RFI from the house.

I wouldn't recommend the Kaz since it is optimized for BCL work. The K9AY is about as easy as it gets to obtain four directions. If you don't really care about four directions, put up just one of the loops or go with the EWE.

The downside of the terminated loops is that they have a fair amount of high-angle response (due to the sloping or horizontal wires). This "lets in" more noise. Sometimes the high angle response can be helpful, if the path and propagation are favoring it. Most often on DX though, my Beverage is superior to the K9AY.

If you want to remove the high angle response, go with two phased verticals. Once again, they do not have to be full-sized. Make then small with some top loading, resonate with a toroid and load with a resistor to match to 75 Ohms. From there, the phasing is easy since mutual coupling is swamped out by the resistive loading.

Or you could try the Double Half-Delta Loop antenna. It claims 2.5 dB better RDF. See the attached file. You can get an EZNEC model at the Chesterfield Islands DXpedition page.

[WA1GFZ]

A vertical working into a source follower would drive coax. It would also be broadbanded. I have a pile of aluminum tubing so might be worth trying. I've read the horizontal wire is an issue with a short antenna.
Still the K9AY is so easy. Oh well spring is a ways off and I'm concentrating on the afterburner right now.
Steve do you have any feel for the dB difference between Bev and AY on 40M going East?

[Steve - WB3HUZ]

The dimensions of the loops given in Gary Breed's original article are too large for the K9AY to be effective on 40 meters. He only designed the thing to work on 160 and 80 meters. Rob AEX says he gets some directivity on 40 with his. I don't see any on mine or any that relates to the selected direction. It does seem to be the best antenna for receiving signals from South America. So, if you want to use a K9AY on 40, you can make it smaller. This will reduce the gain on 160, but maybe that's not a concern for you.

A one-wavelength Beverage on 40 will still be better than an optimized K9AY or EWE, etc. The RDF is better by 3 dB and the DMF is better by 8 dB, both significant improvements. If you put up two side-by-side with an offset and phased them, you'd see another db or two improvement in the RF and probably another 8 dB in the DMF (T-storms from the south would just about disappear).

[WA1GFZ]

Gee I could do 120 feet but for facing east it would take some coax. Heck I could do a pair of them on each side of the yard. On the north side we have bushes and on the south dog woods.

[Steve - WB3HUZ]

If you can space them over one-half wavelength, go with broadside feed - just combine the two and off you go. This will give you a big RDF improvement but not much DMF improvement. But you can also space two only 15 feet and use end-fire phasing. Here you won't get as much RDF improvement but a big DMF improvement.

The coax is easy. Use R-6 or 59. It's cheap and low loss. I use the flooded RG-6 and I bury it. This gets it out of the way and removes or reduces common-mode noise pickup.

[W1GFH]

The "Super Kaz" is the way to go for receiving antennas for those who don't have the acreage for a Beverage.

And for those who want something even smaller (table top size), you could try the "crochet hoop loop", an 80m receiving antenna idea I found on a VK ham's site:

http://blog.marxy.org/2008/12/80m-receive-loop-antenna-on-crochet.html

It uses a strip of 6 conductor computer ribbon cable wrapped around a (18") wooden crochet/embroidery hoop. The tuned section is made from the first 5 conductors. The pickup loop is made from the 6th conductor. A very close coupling arrangement, nonetheless, the 365pf junk box variable cap I used produced a sharp peak to bring in strong 75 meter ghetto sigs using my little Degen 1103 SW rcvr, with the bonus of being able to null out local noise.

[WA1GFZ]

Gee I could get them 80 to 90 feet apart. East end would terminate into sand  near the street. Do you think I should do anything special with a crappy ground termination. Out in the back the ground is pretty hard again a poor ground for the transformer. 

[Steve - WB3HUZ]

The ground is what it is. Don't worry about it too much. If you can, pound a 2-3 rods spaced the length of each rod and tie them together. Ninety feet is about 0.66 WL, perfect spacing for a broadside array. You'll be able to hear a pin drop in EU!

[WA1GFZ]

This past week I built a few RX antennas at GFZ south. First a 160 foot beverage facing west.
Then I put up a KAZ on the other side of the yard to favor east. The KAZ was 50 foot base about 20 feet at the apex. Everything worked as expected but I found as the frequency was increased The KAZ started working to the west (feed is on the east side). I found as the top wire length approached a quarter wave RX signals  got stronger than the beverage.
Then I made the KAZ bigger. 85 foot base, 30 feet tall. WWVH on 15 MHz was stronger on the KAZ than the beverage.At 10 MHz WWV was about even.
The last configuration of the KAZ was a taller apex. 50 feet wide and 30 feet tall.
This was almost useless on 40 meters with no real F/B. It did do well on 75 meters and below though. WWVH on 10 meters was equal with the beverage.
The BBC at 7.255 MHz the beverage worked better off the back.
I was using a step attenuator on the antenna to measure performance switching between antennas.
Next trip I will build a smaller KAZ to get better performance on 40 meters.