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I have just installed an Aziloop and I do not get good nulls - 10 -15 dB on 50 -100-mile ground wave signals,
Loop is 13' on long side, 8' on short side and PVC mast is 15 feet. Radials are on the ground below the loop elements. It is fed with about 200' of RG6 cable and the?supply voltage is 12.7 volts.
I have a SAL-20 antenna 40 feet north of the AZI.? I can get 15-30 dB nulls with it.?
I have a 60 foot self-supported welded steel tower with a large 10–40-meter Mosley beam at the top 42' east of the Azi.
Antennas are in the middle of a 1.5 acre lot - no other buildings or metal nearby.? Ground elevation is 15 feet ASL.
Could these two other antennas be affecting the poor null operation on the Azi???
Any suggestions would be appreciated.
73,
Bill, WA2DVU Cape May, NJ 609 425 8651
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Hi Bill,
I suggest you model your exact antenna and radial dimensions in eznec and check f/b at 2 degrees. Try optimising the f/b with a resistor 100-600 ohms in series with insulated radials on their own. You can add the other structures to see their effect.?
73
John
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Hi Bill
On what frequencies?
Simon g0zen
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363 930 1030 610 khz.
73,
Bill, WA2DVU Cape May, NJ
On Friday, March 14, 2025 at 10:41:53 AM EDT, Simon via groups.io <ohhellnotagain@...> wrote:
Hi Bill
On what frequencies?
Simon g0zen
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If you are searching for nulls, I find a "shielded" 0.5-meter loop made of 0.5-inch copper tubing hard to beat.? Five internal turns, the center of which is cut and brought out to a home brew and characterized (using an HP VNA) broadband transformer.??
We have a "blowtorch" AM transmitter in Boulder, Colorado on 760 kHz which measures -24 dBm on any of my outdoor dipoles (not cut to frequency - they're all quite short for the frequency).? I'm only some 25 or so miles from the transmitter on the Front Range of the Rockies.? The null with that small loop is so sharp and deep that I'm able to null out that "blowtorch" during day or night (no reduction in power after sunset) to receive other distant stations.? I haven't measured the null depth, but it must be in excess of 40 to 50 dB.
Dave - W?LEV?
On Fri, Mar 14, 2025 at 5:10?PM Bill Riches via <bill.riches= [email protected]> wrote:
363 930 1030 610 khz.
73,
Bill, WA2DVU Cape May, NJ
On Friday, March 14, 2025 at 10:41:53 AM EDT, Simon via <ohhellnotagain= [email protected]> wrote:
Hi Bill
On what frequencies?
Simon g0zen
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Hi Bill
( and Dave) Bill has paid a good few bucks for the Azi-loop if its from UK, so wants it to work as advertised.( if not a knock off.)
It should av a better f/b than that. But Bill remember its just a flash k9ay loop..
Size of loop matters, placement etc..
Bill, if it’s the UK version get in contact with the maker and ask for advice? I just hear good things about them, though it wont be better than a k9ay ( of same size) on a rotator with variable R over a reasonable gnd.
Keep us informed..Simon g0zen
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Understand, Simon.? In retirement, US $$$$ are not an option for me.? That's why, whenever possible, I build my own.
Dave - W?LEV
Hi Bill
( and Dave) Bill has paid a good few bucks for the Azi-loop if its from UK, so? wants it to work as advertised.( if not a knock off.)
It should av a better f/b than that. But Bill remember its just a flash k9ay loop..
Size of loop matters, placement etc..
Bill, if it’s the UK version get in contact with the maker and ask for? advice? I just hear good things about them, though it wont be better than a k9ay ( of same size)? on a rotator with variable R over a reasonable gnd.
Keep us informed..Simon g0zen
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Hi Dave.. totally agree..when comes to antennas I hate to buy!!
However, not all feel the need to do so, or have the time to do.
(Dave you are on rsgb technical, you have no doubt seen my thread on short marconi T for 160m and the quest to improve, so on same page. (Getting better btw, vk’s on ft8 now.))
The “ standard loop” has short falls .. bi directional being one..(hence the k9ay/ azi- loop.) Ie yes ( standard loop) stunning null, but not much use if ( example) dx is north and qrm ( from local station) is south.
Simon g0zen
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Well, the truth be known, I mostly use the 0.5-meter "shielded" loop for DF'ing RFI.? It's great for that.? But, yes, the null is bidirectional.
Dave - W?LEV
Hi Dave.. totally agree..when comes to antennas I hate to buy!!
However, not all feel the need to do so, or have the time? to do.
(Dave you are on rsgb technical, you have no doubt? seen my thread on short marconi T for 160m and the quest? to improve, so on same page. (Getting better btw, vk’s on ft8 now.))
The “ standard? loop” has short falls .. bi directional being one..(hence the k9ay/? azi- loop.)? ?Ie yes ( standard loop) stunning null, but not much use if ( example) dx is north and qrm ( from local station) is south.
Simon g0zen
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As a constructor, I'd also agree, however in this case I'd be tempted to buy.
?
If you price up how much time, effort and cost, that would be required to develop and build your own version, with comparable features, including the software and remote control functions, I suspect you would be close to the price Dave is charging. I have no affiliation with Dave, but the more I learn about its capabilities, and how well thought out the design and implementation has been, the more impressed I become.
?
If I was more interested in operating, rather than constructing, then I'd definitely buy.
?
Regards,
?
Martin
?
On Fri, Mar 14, 2025 at 06:48 PM, Simon wrote:
totally agree..when comes to antennas I hate to buy!!
However, not all feel the need to do so, or have the time to do.
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I don't doubt.? But I'm retired and have the time.? However, the scourge of retirement:? Have the time but don't have the $$$.
Dave - W?LEV On Fri, Mar 14, 2025 at 7:54?PM Martin - Southwest UK via <martin_ehrenfried= [email protected]> wrote:
As a constructor, I'd also agree, however in this case I'd be tempted to buy.
?
If you price up how much time, effort and cost, that would be required to develop and build your own version, with comparable features, including the software and remote control functions, I suspect you would be close to the price Dave is charging. I have no affiliation with Dave, but the more I learn about its capabilities, and how well thought out the design and implementation has been, the more impressed I become.
?
If I was more interested in operating, rather than constructing, then I'd definitely buy.
?
Regards,
?
Martin
?
On Fri, Mar 14, 2025 at 06:48 PM, Simon wrote:
totally agree..when comes to antennas I hate to buy!!
However, not all feel the need to do so, or have the time to do.
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Here is a list of stations that I used to further check my AZIloop.? I used my trusty Perseus and got better results than from the Apache.? I believe the AZI loop is working ok. I believe low nulls are caused by my SAL and tower being close by.? I will experiment with longer and higher (1 to 2 feet off the ground) and see if that helps the null.
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AZI
LOOP NULLS |
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| FX |
QTH |
CALL |
AZ |
DATE |
EST |
AZI NULL |
LOOP NULL |
| 1060 |
PHL |
KYW |
0 |
03 15 25 |
1000 |
96-82=14 |
100-83=17 |
| 1090 |
BALT |
WBAL |
235 |
03 15 25 |
1000 |
93-79=14 |
90-80=10 |
| 1120 |
MD |
WUST |
270 |
03 15 25? |
1000 |
106-87=19 |
100-87=13 |
| 1150 |
DE |
WDEL |
355 |
03 15 25 |
1000 |
99-80=19 |
103-81=22 |
| 1210 |
PHL |
WPHT |
350 |
03 15 25 |
1000 |
90-76=14 |
98-78=20 |
| 990 |
PHL |
WNTP |
0 |
03 15 25 |
1000 |
90-76=14 |
98-78=20 |
| 980 |
DC |
WTEM |
270 |
03 15 25 |
1000 |
103-88=15 |
107-87=20 |
| 950 |
PHL |
WKDN |
0 |
3 15 25 |
1000 |
80-65=15 |
85-63=22 |
| 880 |
NY |
WCBS |
10 |
3 15 25 |
1000 |
95-87=8 |
103-87=16 |
| 860 |
PA |
WWDB |
0 |
3 15 25 |
1000 |
92-75=17 |
93-74=19 |
| 830 |
PA |
WEEU |
0 |
3 15 25 |
1000 |
98-80=18 |
108-78=30 |
| 770 |
NY |
WABC |
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3 15 25 |
1000 |
91-83=7 |
97-80=17 |
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Receiver -? |
Perseus |
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73,? Bill, WA2DVU Cape May, NJ
On Friday, March 14, 2025 at 02:48:22 PM EDT, Simon via groups.io <ohhellnotagain@...> wrote:
Hi Dave.. totally agree..when comes to antennas I hate to buy!!
However, not all feel the need to do so, or have the time? to do.
(Dave you are on rsgb technical, you have no doubt? seen my thread on short marconi T for 160m and the quest? to improve, so on same page. (Getting better btw, vk’s on ft8 now.))
The “ standard? loop” has short falls .. bi directional being one..(hence the k9ay/? azi- loop.)? Ie yes ( standard loop) stunning null, but not much use if ( example) dx is north and qrm ( from local station) is south.
Simon g0zen
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Hi Bill,
We have not heard further from you so I assume you have not improved your f/b.
I have been using my Aziloop in K9AY mode for a year now and always managed to get groundwave f/b ratios approaching or more than 30dB over the higher medium wave (1.0MHz) to 3.8MHz. My loop is similar size or slightly larger than yours - 20ft total diameter, apex 15ft high, bottom wire horizontal 4ft high. It is completely in the clear.
I have tried various radial systems, either 4x 12ft insulated radials lying on the ground or (now) 4 x 11ft radials 3ft high (1ft under the bottom wires) there is no earth connection apart from the radials, and I get similar results.
?
Possible reasons for poor f/b are:-
?- proximity of metal objects or other antennas, one might expect this worse on some frequencies and directions than others
?- lack of series resistor when using short radial system. Have you modelled your antenna and radial system? This resistor and the loop termination R are interdependent to some degree but both can be optimised
?- connecting both an elevated radial system and earth together
?- common mode affecting your coax feeder. (this affected VLF more on my antenna where the RG6 feeder length is 650ft ). (maybe larger loop size might help for MW-VLF)
?- lack of signal over-ride due poor output of antenna at VLF due to too small loop size or a fault. Have you checked you get in the region of 9 or 10dB noise over-ride when you connect the antenna? (you can do this by disabling the filter for the band you are listening on and LCU preamp, then measuring how much the noise drops on a clear frequency)
?- the K9AY pattern f/b varies with elevation angle the f/b is measured over. The back null can be optimised between about 45 degrees down to groundwave depending on how you connect the earth and type of earthing or radials.
?
Please note there is a difference in polar pattern between a K9AY tuned against conventional ground system (rod, buried radials etc.) and a K9AY tuned only against 4 short radials under the wires (either insulated or lying on the ground) with a series resistor.?
The conventional K9AY with ground rod etc. can have a relatively poor groundwave f/b 10-15dB with sharp null in the back lobe at about 45 degrees. Users of K9AYs say this higher null is an advantage when they can null steer using a vacrol to adjust the termination R.
The K9AY loop tuned against 4 short radials in series with a resistor usually between 100R and 560R depending on bottom heights and spacing has a pattern similar to a Flag or Pennant,? with high f/b on GW signals.
Try modelling them both.
Both modes are only single loops so you cant expect miracles, some days it compares with my beverages, others it is down a few dB as you might expect from the comparitive RDFs of a K9AY and beverage. However its remote steerability to 5deg azimuth and termination adjustment make it a very useful antenna like no other on the market.
Good luck
73
John
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PS I hate to buy also and up until now have made all my own RX antennas but cannot possibly replicate Dave GW4GTE's years of development and computer skills designing a desktop DF antenna providing remote site capability and desktop application. Unfortunately it is more expensive now reflecting dealer mark up and support costs.
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Bill, My reply crossed with yours. Glad your results are better. My nulls in both loop and K9AY modes are very close to the bearing -180deg as expected, when f/b is optimised
73, John
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However its remote steerability to 5deg azimuth and termination adjustment make it a very useful antenna like no other on the market. That's exactly how it is! Thank you, John, for the solid explanation. I am fascinated that despite the relatively small size of your AziLoop, you are often able to compare it with the Beverage and sometimes achieve similar results. Do you mostly work with the Azi's preamplifier here? 73 Christoph —
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Hi Christoph,
Yes I need the (remote) preamp nearly all the time to get sufficient s/n over-ride not helped by feeder length of <200m.. Multi-joined RG6 most over 30 years old with loss about 4dB at 1.8MHz, loop R=10 ohms..
At VLF I find its conventional loop mode better and I did manage to hear the SAQ Xmas transmission on 17.2kHz.. Not as good as other larger antennas because of a 20kHz HPF.
A K9AY does not work as well at VLF. Modelling my loop gives a very low -69.5dBi at 300kHz, and only 5dB better if conventional earth used. Worse at 100kHz. Others may comment on what size (conventional?) loops are best for reception down on VLF frequencies and what sensitivities are needed, I would imagine it has been discussed on this forum before!
73
John
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Hi Christoph,
re. Loop and Beverage comparisons
My 160m - 220m beverages are usually about 3dB better in s/n than the K9AY loop on 1.8 and 3.5MHz in their design directions, as one would expect from the comparitive RDFs, but there are days and directions where the K9AY or conventional loop is as good, possibly because of steerable direction, nulling noise or favourable pattern. It appears to work comparitively well in disturbed conditions.
73
John
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My 160m - 220m beverages are usually about 3dB better in s/n than the K9AY loop on 1.8 and 3.5MHz in their design directions, Thank you John. That is very impressive for the relatively small size. Thanks to the tips here in the group, I am very optimistic that I will be able to erect an AziLoop with the 13.8 metre circumference mentioned in the forthcoming manual - and that this antenna will serve me very well for mediumwave reception. 73 Christoph —
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Bill Riches
Christoph Ratzer