Topband: [Bulk] Improving low angle reception DX Eng 8 ele Circle RCV Array

[donovanf at starpower.net]

Hi Doug, 

I also use passive verticals in my 350 foot diameter W8JI 8-circle array. 
Reliability has been excellent (no failures in three years) because there 
are no sensitive electronic components in the array, except for the 
relays at the center of the array. 

Many deer traverse my receiving antenna field day every day (they live 
in the wooded margins of the field), but I've never had a problem with 
them getting tangled in the top hat wires because they're attached to the 
tops of seven foot fence posts. 

I'd surprised if a 100 foot diameter triband 8-circle could be very 
effective on Topband. The 35 foot distance between verticals is so small 
(less than 25 degrees of phase) that almost the entire signal is cancelled. 
On the other hand, 70 foot spaced receiving verticals work well if phase 
and amplitudes are accurately controlled. The pattern of 1/4 wavelength 
spaced verticals is slightly worse, but its much less sensitive to amplitude 
and phase errors. 

Yes, directivity is significantly reduced for very high angle signals because 
the wavefront arrives at all of the verticals at nearly the same phase. 

73 
Frank 
W3LPL 



----- Original Message -----

From: "Doug Renwick" <ve5ra at sasktel.net> 
To: "Grant Saviers" <grants2 at pacbell.net>, "W0MU Mike Fatchett" <w0mu at w0mu.com>, topband at contesting.com 
Sent: Sunday, March 1, 2015 9:37:41 PM 
Subject: Re: Topband: [Bulk] Improving low angle reception DX Eng 8 ele Circle RCV Array 

Hmmm. I have had excellent success with that DXE 4- quare system. I use my 
own verticals and the only problem is deer catching the top hat string and 
bending the vertical. 70 ft baselines seems short as the recommended is 135 
ft for 160m. I find it very forgiving as the system works even if the 
verticals are not tuned correctly. Best receive system ever for me. 
Sometimes too much directivity especially in a contest, if there can ever 
be too much. 
Doug 


-----Original Message----- 

My 4 sq DXE exhibits similar "no directivity" at times. I think it is 
high angle signals. I did add three 20 foot radials to each antenna, I 
don't think it matters what the vertical element is, a little better 
grounding is good. My soil is wet/swampy forest/grass mix and I don't 
think they made much difference. I put the radials along the square 70' 
baselines and pointing outward outside the square to minimize any 
coupling to the feedlines to the switch box in the center of the array. 

My BIG problem is an intermittent S9+40 noise generated within the 
array. Comes and goes, so it is very hard to troubleshoot. I've 
disconnected each antenna one by one, checked, cleaned and reseated 
every cable, varied the power supply voltage, had the DXE preamp in and 
out and not found it. VERY frustrating!! I did find the antenna amp 
pcb's had not been flux cleaned and at each F female connector a lot of 
corrosion products had built up. I think this is because of the 
sustained DC voltage on that connector. Removing the white crystalline 
gunk that went from F center to the 4 soldered legs made no difference. 
My next step is to take apart the switch box and see what is going on 
inside it. DXE won't provide schematics, but I did find the W8JI patent 
which I think is what DXE is selling. 

It's a very good antenna IMO, but DXE needs to have better QC. Residual 
flux is bad and although the antenna enclosures are well made, they 
aren't water tight. Probably the boards should be conformal coated 
given the WX exposure, but that makes them harder to fix. 

Grant KZ1W 


On 3/1/2015 10:52 AM, W0MU Mike Fatchett wrote: 
> I just recently hooked up my 8 ele rcv array and I was not too sure if 
> it was working correctly. 
> 
> I will need to do some maintenance and checking when the snow is gone 
> to make sure each element is working right. 
> 
> I chose the 160/80/40m which is close to 50 ft radius circle. I may 
> opt to make it bigger if the area I have will allow. 
> 
> Last night in the NA QP RTTY contest the array seemed to be working 
> fine and was quite directional on stateside signals on 40 and 80. I 
> am seeing directivity on 160 with local broadcast stations. 
> 
> I was listening to the 3G0ZV station last night on 80 and he had a 
> good signal. His signal did not seem to change much when I changed 
> directions on the array. I was unable to work him though :( But that 
> is an Xmit antenna issue. 
> 
> The array is placed over what it probably poor sandy soil. W3LPL 
> mention in some of his talks that he was adding some radials to his 
> receive array. His elements are a bit different than the DX Eng 
> antennas so I don't know if this would help the DXE elements. 
> 
> My feeling is that the array could use some improvement in the low 
> angle reception. I feel that it should hear better to Europe and Africa 
> 
> When I had just the 4 SQ Array up in Montana it was like night and 
> day. EU Signals that were not copyable on the 80 xmit antenna were 
> perfectly copyable on the 4 sq array. I am not seeing that on the 8 
> ele array. 
> 
> Conditions are always different so maybe it is fine but condx have 
> been poor? 
> 
> Thanks for your suggestions in advance! 


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