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eHam Forums => SWL (Shortwave Listening) => Topic started by: K0OD on September 14, 2013, 08:48:44 AM



Title: New Shared Apex Loop Receiving Arrays
Post by: K0OD on September 14, 2013, 08:48:44 AM
Two new antennas from Array Solutions would seem to be the ultimate receiving antennas for listeners and many hams. The AS-SAL-20 covers VLF, BCB, and shortwave to 15 MHz  Can be switched remotely and instantly in 8 directions (or omni)  and offers high f/b and f/side. No radials required.

A smaller version covers BCB to 30 MHz.

http://www.arraysolutions.com/Products/sal_array.htm

Are these being shipped now?  Thoughts?  Price (from what I can tell) is under $800.

(http://www.arraysolutions.com/images/SharedApexPhotowebweb1.jpg)


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KZ1X on September 21, 2013, 03:10:04 PM
I actually asked to the eHam gurus to put up a new review category for such items, especially this one, to encourage reviews to be posted.  Hasn't happened yet that I know of.

The antenna you mention is supposedly shipping.  There are many articles written and YouTube videos of it in operation.  So I am certainly intrigued.

I want to buy one, like soon, but I do not want to be an early adopter.  Hopefully Jay will ask some of his customers to post reviews.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KD8IIC on September 21, 2013, 05:34:06 PM
 I believe the antenna in question is the K9AY designed by Gary Breed. It has been around for some time. If you were going to make such an investment, and take the hours needed to install, I would rather encourage one to look into the Pixel Pro 1 Loop of which I have two installed at my QTH. Quite the good investment and it takes up so much less room. All that is needed is a 4 foot mast out of the ground and a low priced TV antenna rotator.The very low noise pre-amp is built in and you also get a TR switch built in to mute the pre-amp and rf to your receiver when transmitting. 
 All stated, I did build a K9AY and was not impressed with the performance compared to what I bought from Pixel in 2010.
  73 from Lane in Ohio  de n8aft  sk  ..


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on September 21, 2013, 07:37:00 PM
It resembles the old K9AY antenna physically. But K9AYs have a broader pattern and reduced bandwidth. 

The Shared Apex Loop Array pattern resembles that of a 4-square phased vertical array. The Array Solutions system can be instantly switched in eight directions, or made omnidirectional or bi-directional. The direction can even be flipped to see front to back or to check long path. No conventional mechanical rotator is used. No separate control cable is required. 

This would appear to be far superior to Pixel or Wellbrook type loops which are fairly omnidirectional except for reduced pickup off each end. Those nulls, I believe, are mainly effective for reducing local noise from power-lines, nearby home appliances and such. Local crud. They can be useful for reducing problems caused by local high power transmitters. But they won't null skywave signals. Steering a Pixel loop can be done by hand or by slow mechanical means.

The Shared Loop should lower skywave AND ground wave interference.  In fact it can reduce interference from atmospheric noise or distant radio signals over about 80% of the azimuth at a time.

I've used a 4 element phased vertical array on 40 meters years ago for both transmitting and receiving. It worked fabulously especially on receive but it required a lot of space and a full radial field for each of the four verticals. No radial system is required for a Shared Loop Array.

Main caveat I see is that the array should be located in the clear. Array Solutions suggests that it should be >100 feet from homes.  I wondered whether the vertical center support can be hidden in a tree, or can be a tree. Cutting the lawn under the array could be a problem. In my location, deer would be a concern.   

Article from QEX:
http://www.arraysolutions.com/Products/SAL_shared%20apex%20loop/PDF%20Files/Bauman%20Sept%202012.pdf 

 


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: W4OP on September 21, 2013, 08:48:17 PM
I use the Pixel loop and remotely rotate it in azimuth and elevation achieving good night time nulls as well as daytime. Working on an Arduino micro to auto null.
A lot smaller than the K9AY and less expensive.
Dale W4OP


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K5RT on September 22, 2013, 07:42:36 AM
This antenna is not, or anything like, the K9AY antenna. The Shared Apex Loop Array operates on a totally different principle.

Recent testing indicates the Shared Apex Loop Array has proven the antenna pattern is not terribly affected by nearby objects.

Mine is about 30 feet from overhead power lines, it's about 60 feet away from the tower, 75 feet away from the 160 meter vertical and about 120 feet from the 80 meter ground plane. The pattern is very good and F/B is exceptional.

The concern about locating in close proximity to nearby metal objects, houses and such is due to re-radiation of very strong signals, man made noise from plasma TVs and what have you.

Don't forget, your transceiver needs to be properly configured to use an external recieve antenna.

Guys, this is the antenna you want if you are unable to install Beverages. The Shared Apex Loop Array performs as well as the Hi-Z antennas at a much lower price. It runs rings around the K9AY, EWE, Pennant/Flag, BOGS or Small magnetic loops. It's the real deal.

At my station, the ambient noise on 80 and 160 is S8 to S9. The SAL solves that problem! It won't fix bad band conditions, but it enables me to copy 3 or 4 layers of stations during a contest that I couldn't copy otherwise.

Call or email Array Solutions for availability, they should start shipping very soon.

Vy 73
Paul


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KB7GF on September 22, 2013, 07:57:24 AM
Good Morning Guys,

Just wanted to clarify a few points on this thread and it is a good discussion.  The Shared Apex Loop Array (SALA) is quite different from the K9AY in operating principle and performance.  It utilizes broadband loops (each loop being similar, although physically larger, than the Pixel Tech or Wellbrook loops).  It differs from a foursquare array in that it uses broadband loops rather than vertical elements.

The array combines the signal of an electrically small loop with a delayed signal from an adjacent electrically small loop.  In this manner, two loops and a single delay line can provide both front to back rejection and front to side rejection - especially on vertically polarized signals - and can provide this directivity over a wide range of frequencies.

The array does not require an RF ground.  As far as distance to other objects, modeling shows that there is some interaction; however, my array is located 50 feet from my house and I have good directivity from 500 KHz to 10 meters.

73,

Mark KB7gf  


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on September 22, 2013, 08:28:15 AM
We've hit the SALA information jackpot. Mark holds the patent on it. Welcome guys. www.widebandloop.com

What about using a tree for the center mast?


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KB7GF on September 22, 2013, 08:51:26 AM
Hmm...a tree for the center mast.  It is non-conductive (that is good) ... the spacing is more than necessary, but wouldn't be a problem if it was modeled. The biggest problem would be keeping the loops the same size and shape...very critical, especially at low frequencies.

73,

Mark KB7GF


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on September 22, 2013, 10:51:39 AM
Quote
Hmm...a tree for the center mast.  It is non-conductive (that is good) ... the spacing is more than necessary, but wouldn't be a problem if it was modeled. The biggest problem would be keeping the loops the same size and shape...very critical, especially at low frequencies.

Is the supplied wire insulated?

I'm thinking in terms of my 60' tall Pin Oak trees which have bare vertical trunks that go up about 30 feet to where the tree branches out. Trees aren't exactly non-conductive. In fact they have been used by themselves as verticals. Military did a lot of tests on that long ago. Drive a nail into the base of a 100 foot tree and you're on the air in 5 minutes!

I don't foresee problems (at my QTH) making the loops even. A few minutes with a tree saw will take care of that.  What about the loop bottoms? My yard, like many,  isn't perfectly flat.

Thoughts on grass mowing and critters... real world problems that a lot of buyers will wonder about?


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K5RT on September 22, 2013, 11:02:24 AM
Some other points to note about the antenna. Or more like to all antennas. The pattern is three dimensional. For example, on the AM band, I notice different Front/Back values vary from station to station. This is due to the ground wave component, vs skywave component. Or to put it another way, angle of arrival of the incoming wave.

I had Beverages up for several years, until the pasture behind my QTH grew a bunch of McMansions. IMO, the SAL is a very close performer to what I remember my Beverages being.

It won't cure power line noise, or spurs from plasma TVs or the common cold, but it will open a new world of low band DXing for you. And looking at the sunspot cycle predictions, this is where you want to spend your hard earned consumer dollars.

Yes, the wire being supplied for the loops is insulated.

I've had a prototype up for over a year now and I'd rather be QRT on the lowlands than do without the SAL.

Mark is a genius.

Vy 73
Paul


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K5RT on September 22, 2013, 11:05:44 AM
Mowing isn't a big problem. I roll up the RG-6 feed line, and mow around the array with a push mower.

It adds a little time to the mowing chore, but it's a price I gladly pay.

Mark will have to speak to the effects of uneven ground, but I don't think it's a problem, as long as the base leg of each loop is at the same elevation.

Paul


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KB7GF on September 22, 2013, 04:59:52 PM
We have been recommending that the ground be flat under the array because all of the installs to date have been on flat ground.  This may be overly conservative, however, because modeling of a single loop measured at various heights above ground (between 2 to 8feet) provide the same signal response, so this makes me optimistic that the array would work on uneven ground. 

The array will work fine if the loops are elevated.  I do recommend that the array not be tilted though, because this make the takeoff and null angles different depending on which side of the array you are pointing.

Good point on tree conductivity.  I know from testing and modeling that a SALA supported with a metal mast that is inserted into the ground several feet will not work.  Modelling does predict that a metal mast that isn't connected to the ground will work - although I have never tried this.  The model doesn't handle moderately conductive masts that are connected to the ground very well - so the only way to know would be to test it. 

73,

Mark


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on September 22, 2013, 08:29:50 PM
Thanks guys.  Can the whole array be elevated to position the horizontal wires - the bases of the triangles - above head (and antler) level, about 7' above ground? Perhaps the diagonal wires could double as guys for the taller mast.

In other words, can your array be elevated in the same way a 4-square vertical array can be elevated? Elevated 4-squares work somewhat better than ground mounted ones.

(http://www.widebandloop.com/Images/SharedApexDualLoopArray_web.jpg) 


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KB7GF on September 22, 2013, 09:57:45 PM
Yes, modeling teaches that the loop bases can be elevated - above heads and antlers.  The limit seems to be around 1/4 wavelength base height at the highest frequency of interest.  So, if you have a small array and are interested in directivity all the way up to 29 MHz, then you should keep the loop bases below ~ 8 feet.  If you have a larger array and only interested up to 15 MHz, then you could put it as high as 16 feet.  If you only care about 1.8 MHz, then you could put it up to a height of 40 meters!  You would lose directivity, though on the bands above 160m.

73,

Mark KB7GF


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on October 06, 2013, 09:23:47 AM
An open Yahoo Group for Shared Apex Loop Arrays has just fired up and is picking up followers fast.

It can be found at:  http://groups.yahoo.com/neo/groups/sharedapexloop/conversations/topics

Group Settings
  • Public group.
     -   Attachments are permitted.
     -   Members cannot hide email address.
     -   Listed in Yahoo! Groups directory.
     -   Membership does not require approval.
     -   Messages are not moderated.
     -   All members can post messages.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on October 08, 2013, 11:53:32 AM
Quote
The Shared Apex Loop Array pattern resembles that of a 4-square phased vertical array. The Array Solutions system can be instantly switched in eight directions, or made omnidirectional or bi-directional. The direction can even be flipped to see front to back or to check long path.

Correction from Mark KB7GF, the SALA's inventor:

"Just a point of clarification on the omnidirectional reference.  The prototype unit mistakingly had an OMNI button - and it got photographed - but it should have been a UNI button (meaning uni-directional).  The production units have both a UNI-directional button and a BI-directional button ... but NOT an omnidirectional button.

Just wanted to clarify that.

Mark  KB7GF"




Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KZ1X on October 20, 2013, 09:05:21 PM
I am anxiously awaiting one or two eHam.net product reviews to get posted on this new antenna.

Anyone out there who's purchased the SALA (a production unit from Array Solutions) and can write up what they've found, would be terrific.



Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on October 21, 2013, 08:10:32 AM
Can't imagine what the usual dopey Eham antenna review would add to the QEX article, the info from the new SALA Yahoo group and several YT videos that show the antenna in action.

I don't own a SALA yet, but if you insist on a review:

"I put up a SALA 15 minutes ago. Our local 50 KW Clear Channel AM
 station comes in great. Built like a tank.
It's a keeper. Mark's a great guy, Jay's a great guy.
Did I mention it was built like a tank?
" :)


Seriously, my main concern would be concealing one in our yard, away from the house and other antennas and so deer and our lawn service don't take it out. I'd like to hear comments on the quality of the switching box. Videos show several box versions. A good place to find knowledgeable performance evaluation would be low band ham DX/contest groups. Those guys won't pull punches.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KZ1X on October 23, 2013, 03:52:32 PM
Jeff, you have missed your calling as a comic.  You nailed the typical newbie-review format there, just too funny.

Seriously, I agree, the reviews themselves are often pointless.  However, numerically, they tell a tale of adoption ... if there are several eHam.net (or other) reviews from "Joe Ham" ... that means that Jay sold some of these skyhooks and is getting feedback from people other than those who were selected to test the thing in the first place.

That just means I don't have to go "first" (at list price) and wring out any little gotchas.

What I have seen so far is that Jay's reported he is still finding ways to ideal the F-B for example.  That's good news, but, it causes me to delay my purchase, waiting for the jury to return on actual use-case best practices.  The reality is that the number of these units deployed is still de minimis.  I am kind of not wanting to be an experimenter with this antenna, right at this stage of my life.  I've spent the last 30 years being an early adopter.  It's become old.  I'd just rather go and install it and use it.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on October 25, 2013, 04:16:37 PM
I often think of a rave review I saw from a new American ham using one of those built-like-a-tank pileup-busting Wonder Verticals.... a/k/a a big and costly aluminum stick. He boasted that he used it to work an Egyptian and a Pakistani contact on 40 meter sideband while running 50 watts in the CQWW contest. As an old 40-meter contester/DXer, I had doubts.

Turned out the Egyptian was a bootlegger and the very rare Pakistani sideband Q was with a military prefix never used by hams. Likely the reviewer had mis-copied the call and his logging program listed it as Pakistan. Otherwise his contest Qs were utterly unimpressive.

I share your observations on the newly invented SALA. I'd like to hear from users of production units and not from beta-testing pals of Jay, the seller,  or Mark, the inventor. I'm in no hurry to buy one. For some reason it doesn't appear that many are being sold. I don't doubt their claims, but effectively shrinking the equivalent of a wheel of 8 long (long enough to be effective to 100 kHz!) Beverages down to a radius of 10 or 20 feet is one heck of an antenna breakthrough. 

Why don't YOU buy one and tell me how well it works?  :)


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KZ1X on October 26, 2013, 08:01:59 AM
"For some reason it doesn't appear that many are being sold."

That's cause they are like $600 or whatever.  Not an impulse purchase.

Now, I realize that this cost is a fraction of the actual cost of installing the only two viable alternative antennas, and that's only if one has the space for either of them.  So I am not questioning the value.  Further, I don't feel like buying a large quantity of the ferrite bead doo-hickeys that I'd then have to hand-sort for a match, which I assume/hope is what Jay is doing.  And, I don't want to design and make my own snazzy looking control head or weatherproof delay switcher/preamp/bias-T box.

If you think of all that work that's gone into this antenna, this price is a screaming bargain. 

But ... I just don't want to go first.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on October 27, 2013, 09:21:51 AM
Actually the array costs almost $800.

Some savvy LW/BCB DXers experiment with sophisticated listening antennas and have conducted antenna comparison "shootouts" from sites on the Atlantic. Dallas Lankford publishes his findings on this "read only" Yahoo group:
http://groups.yahoo.com/neo/groups/thedallasfiles2/info

Here WA1ION has links to all sort of longwave and BCB listening wisdom:
http://www.qsl.net/wa1ion/weblink.htm

Here's a BCB DX website that actually has a link (no discussion) to SALA information:
http://am-dx.com/

Would be great if those guys tested the Shared Apex Loop Array.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on November 19, 2013, 10:05:29 PM
I am anxiously awaiting one or two eHam.net product reviews to get posted on this new antenna.

Anyone out there who's purchased the SALA (a production unit from Array Solutions) and can write up what they've found, would be terrific.

Here you go, Steve. Two very brief SALA reviews have just appeared on eHam:
http://www.eham.net/reviews/detail/11399 


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: AI2N on November 20, 2013, 06:07:18 AM
I'll be using a SALA, along with my trusty Flags and BOGs, for CQWW CW this weekend, concentrating on 160m.  I'll submit a review after that. 

Preliminary observations:  the performance of my AS-SAL-20 is commensurate with what is seen on the videos.  It is outperforming my 14' x 29' bi-directional Flags (bottom wire at 6').  The "BI" mode is especially impressive if noise off the back is not an issue. 


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on November 20, 2013, 09:48:02 AM
I'll be using a SALA, along with my trusty Flags and BOGs, for CQWW CW this weekend, concentrating on 160m.  I'll submit a review after that. 

That's fabulous, Redd!

Been waiting for some grizzled low band DXer/contester to bring a SALA to a battlefield, like the CQWW DX this weekend.... someone who can run a/b comparisons that are almost always missing from EHam soft toss reviews.

Want your opinion of it on other bands too, and maybe the AM BCB and ham 630 m experimental allocation (around 473 KHz) if you have a way to listen there.
 


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: AI2N on November 27, 2013, 10:10:45 AM
See my review, up now.

160 meter condx for CQWW DX CW were very disappointing.  I worked everything I heard but didn't hear much.  Naturally, condx were better on Monday.

I managed to work YN2CC on 160 last night BUT the SALA and my 125' BOGS couldn't hear him at all, whereas my Flag antenna (14' x 29', bottom wire 6' above ground) could.  The SALA is -generally- better than my flags, but more is always better.


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K0OD on January 31, 2014, 07:24:52 PM
February 2014 PVRC newsletter review of the SALA:

http://pvrc.org/Newsletters/feb14.pdf


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K1DLM on May 29, 2014, 03:49:13 AM
Mark,

I was just watching your YouTube video, and had a question.  I'd like to install on the side of a hill in my back yard. In your video, you indicate the shape of the loops is unimportant, as long as they're all the same. So, do you see any issues if I use more of a pennant shape (I.e. No flat bottom, but rather an elevated outside corner to the loops)?


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: K1FPV on June 12, 2014, 01:38:57 PM
Well, I haven't tried the New Apex Loop Arrays but did just purchase the Pixel Technology's RF PRO-1B and temporarily hooked it up just at about 4 feet above the ground next to my house and adjacent to a number of trees. The results were astonishing! I intend on moving it into an area of my lot with no trees nearby, on a 6 foot tall pole with a TV antenna rotator and can't wait to see the results!

I'll keep you guys posted on how it does.

73,
Bill
K1FPV


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: KB7GF on June 21, 2014, 12:53:06 PM
Hi David,

Yes, you are correct about the shape of the loops - they just need to be the same shape (and size) and be symmetrical relative to the axis of the mast. However, the coupler location will be different than what is stated in the Array Solutions manual. The manual specifies that the base of each loop needs to be truly horizontal. When using a loop with the bases having an upward slope, the couplers need to be located closer to the mast.

The coupler location can be determined by running the antenna model (you can find a copy in the files section of the Shared Apex Loop Yahoo group :  https://groups.yahoo.com/neo/groups/sharedapexloop/info ).  Or, you can post your desired dimensions, and I'll be glad to run the model for you.

73,

Mark KB7GF

P.S. The Hamvention 2014 Antenna Forum Shared Apex Loop presentation has a short discussion about the loop shape and is located at this URL: http://youtu.be/i46kR0pynFw

Mark,

I was just watching your YouTube video, and had a question.  I'd like to install on the side of a hill in my back yard. In your video, you indicate the shape of the loops is unimportant, as long as they're all the same. So, do you see any issues if I use more of a pennant shape (I.e. No flat bottom, but rather an elevated outside corner to the loops)?


Title: RE: New Shared Apex Loop Receiving Arrays
Post by: N0SYA on June 23, 2014, 06:04:30 AM
Something about sharing and $800 seems mutually exclusive.