Flex 6500 and Shared Apex Loop Array (SAL-20) - A Winner

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I purchased the  Shared Apex Loop Array (SAL-20) from Array Solutions while at the ARRL Centennial Convention. I finished putting the antenna up yesterday.

Preliminary test results using my Flex 6500 are absolutely stunning!

I used the WRDW AM carrier (1630 KHz) as a test signal for checking the pattern. With the antenna pointed (it's electronically steered) at WRDW (10mi away) I measured the carrier at -60dbm (~S9 +12db). Flipping the antenna 180 degrees the carrier dropped to -95dbm (S5.5).  30+db front-to-back!!

The audio was completely unreadable off the back.

Additionally, I checked the noise floor against my other antennas:
    On 160M, my daytime noise floor on the inverted L is between S7 and S8 (normal for residential noise). Switching the SAL the noise floor drops to S4 - S4.5!

    On 80M, my OCF dipole at 40' has a noise floor of S7.  The SAL noise floor is at least 1 S unit better.

    On 40M, the OCF has a noise floor of S5. Again, the SAL noise floor is at least 1 S unit better. In addition, while listening on 40M last night the static crashes were noticeably less severe.

In summary, the Array Solutions SAL-20 isn't cheap but the performance numbers are real and it's a great solution when you don't have the space for beverages. I'm really looking forward to the winter low band season.

Dave,  WB5NHL
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Dave - WB5NHL

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Posted 4 years ago

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W5XZ - dan

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why wait for winter? JH7PFD, VK3QX, VK6GX, and VK4QC were all workable this morning...1824.5...

'just saying'....73, good luck, W5XZ, dan
(Edited)
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Dave - WB5NHL

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Now I REALLY need to polish up the CW skills hi hi
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W5XZ - dan

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naw...nobody was going over 20 wpm!!
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Dave - WB5NHL

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Saw that you spotted VK3HJ this morning  no sign of him this morning in SC
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W5XZ - dan

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k4iqj had some prop to vk this am; dick is in Auburn, Al...there is usually a profound peak right around local sunrise, FWIW...
(Edited)
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Al / NN4ZZ

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Dave,
I have one of the Array Solutions K9AY loops I use for 80M and it also works well on my 6700   I've heard the Shared Apex Loop Array (SAL-20)  is even better. 

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
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Barry N1EU

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The lower noise floor might simply be a result of lower overall antenna gain.  Does an s9 signal on the OCF read s9 through the loop or is it lower?
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Dave - WB5NHL

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Using the same test signal (WRDW) this morning on 1630kHz.
On inverted L   carrier -> -55dbm (S9+20)   noise -> -85dbm (S7)

On the SAL       carrier-> -65dbm (S9+10)    noise -> -105dbm (S4)

Looks like carrier/noise  30db vs 40db clearly favors the SAL by about 10db at least for this test.
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Ken - NM9P, Elmer

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I ran several shifts of W1AW/9 40 SSB (Indiana) this past week and I really could have used a 10 difference in S/N ratio.  I would have made a bunch more contacts because so many stations were right down in the noise on my 6500 and I STILL couldn't pull them out!
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Dave - WB5NHL

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I'm still in the testing phase regarding the SAL-20 and sky wave signals. WRDW being only 10 miles away was probably ground wave at 1630 kHz. NEC modeling suggests good rejection at about 30 degrees arrival (on axis) but finding good stable sky wave signals in ham bands is tough hi hi.
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W5XZ - dan

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take a look at WWV on 2.5 Mhz...I find it useful, anyway, to verify an rx antenna pattern...
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Dave - WB5NHL

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Thanks for the idea Dan    I just tried 2.5MHz  WWV was just barely discernible 5-10db above noise between static crashes. Totally lost off the back.  At 5MHz, if I wait for a fade to -95dbm off the back and then immediately flip the pattern I can see almost a 20db jump to about -75dbm To get the measurements I increased the Flex display avg to max and fps to near min.
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Bill-W9OL

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I live in Chcago. very dense neighborhood.
How does it fare against manmade noise when configured on a 35x130 foot lot?
I haven't had the opportunity to find info on this antenna.
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Dave - WB5NHL

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One of the benefits of loop arrays (Shared Apex Loop or K9AY) is discrimination against manmade noise on the low bands. Most low band antennas such verticals, inverted L, or low height dipoles are nearly omni directional and thus receive noise from everywhere. Loop arrays are broadly directional and attenuate noise off the back. Of course, VERY local noise (neighbors) will still be a problem. A small magnetic loop can sometimes null out a local source. Here is what Frank Donovan (W3LPL) had to say about receiving antennas at Dayton's Contest Univ.
http://www.contestuniversity.com/attachments/W3LPL_Receiving_Antennas_2014.pptx