[Hi-zreceivingarraydiscussions] 80ft spacing Phased Line length.

[Lee STRAHAN]

  Hi Roger and Larry, et. al.
   The 80 foot per side 4-square array and 8 element 4-8 Pro array delay values we use are actually a compromise between maximum RDF and Maximum front to back. All elements have the same voltage or current excitation level at 1.0 for modelling and actual circuit adjusted values.  For modelling we use -75 degrees delay on the back element and -217.5 on the middle elements.. Zero degrees on the front element. This gives you at least 20 dB front to back all the way around the main lobe. The modelled side notches and the rear notch are deep beyond what the electronics and mechanical construction are accurate enough to allow. We see typically 30 dB at the notches in the pattern including the actual straight back response. At the same time with these phasing numbers we see 11.7 dB RDF. This has worked spectacularly for many years. Yes, the RDF can be boosted to 12.1 dB BUT, the side lobes are enlarged to only -13 dB below the front lobe. Not worth it in my estimation to gain 0.4 dB..
   Yes Roger you do see around 6 to 8 degrees delay when measuring the controller. Some of that has equal paths and balances out as applied to all three delay paths.  Here is the rub. Each delay path through the combiner has a different intrinsic delay despite the fact I tried to compensate each path. The bottom line is this. You must subtract 1 degree at 1840 KHz from the LONG  delay value you have modelled. This makes our cables we send out for long delay at -74 degrees at 1840KHz. The short delay cable path has a 180 degree phase inversion which makes the required modelled delay value -37.5 which is half the modelled 75 degrees as needed for proper 4-square operation. The error correction for the short delay cable  due to the circuit components is 3 degrees. This makes the actual cable -34.5 degrees which we call the short cable because it physically is but inside the combiner it actually causes a long value of -217.5 . 
   I looked at your model values and I must have something incorrect as the front to back was not what I thought it should be and the RDF was seriously compromised.  What I can guarantee you is that you will be very pleased with the performance if you use our tried and true values as I have explained above.
  Model only long delay -75 degrees Model only short delay cable -37.5 degrees....... Model only!
Actual cable delays to cut.!.   Long delay actual cable -74 degrees . Short delay actual cable -34.5 degrees. These are all measured at 1.840 MHz. 
 Our current supplier of cable causes us to use 43.4 feet for the short delay cable and 93 feet for the long delay cable.
   Funny thing about RF transformers in precision electronics they have signal delays due to the length of the wire and distributed capacitance etc., and display this differently depending on what circuit configuration you are using(1:1, 1.5:1, 180 deg., auto trans. etc.). Its enough to make you grow old before you can get a handle on it.
 Cheers

Lee   K7TJR
Hi-Z Antennas




-----Original Message-----
From: Roger D Johnson <n1rj at roadrunner.com> 
Sent: Tuesday, December 10, 2019 6:24 AM
To: Lee STRAHAN <k7tjr at msn.com>
Subject: Re: [Hi-zreceivingarraydiscussions] 80ft spacing Phased Line length.

Hi Lee...

I did some modeling and optimization for Larry. The phase angles I derived are -121.5 and -243 for 80 ft spacing. Also, I measured close to 8 degrees phase shift through my 4 square box on all ports. I'm having trouble translating these figures to actual transmission line lengths (as usual!). There must be more in the phasing box than in the normal 4 square installation. What is the secret????

73, Roger N1RJ


On 12/9/2019 5:20 PM, Lee STRAHAN wrote:
> Heloo Larry,
>    Just got home,
>       Current numbers measured here is short delay 43.4 feet and long delay 93 feet..
>   The actual length is not super critical but the ratio between the two is important.
> Lee   K7TJR
> 
> -----Original Message-----
> From: Hi-zreceivingarraydiscussions 
> <hi-zreceivingarraydiscussions-bounces at hizantennas.com> On Behalf Of 
> Larry-k1uo
> Sent: Monday, December 9, 2019 10:24 AM
> To: Hi-Z Receiving Array Discussions 
> <hi-zreceivingarraydiscussions at hizantennas.com>
> Subject: [Hi-zreceivingarraydiscussions] 80ft spacing Phased Line length.
> 
> Has anyone got the actual rg6 coax phase line lengths required for the HI-Z 4 square or 4-8Pro based on an 80 ft. spacing?
> 
> Thanks
> Larry  K1UO
> 
> 
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