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post #1 of 8 (permalink) Old 2018-01-23, 08:46 PM Thread Starter
Join Date: Jan 2009
Posts: 452
Post Got bored today

Well the gh has been working well .
So time to build a 8 whisker bow tie.
Didn't model it just built off a half wave length.
So I gathered up some 1/4 inch copper tubing
18 gauge aluminum wire
One them dollar store aluminum thermal covers that measured out 8 foot by 6 I believe .
Some 3/4 inch electrical conduit
And just threw it together lol
But if you want to model it.
11 inch whiskers with 5 1/2 Inch spread
11 inch spacing
Phase lines spaced 1 3/4 inch using a simple X for phase line crossing ( 1 inch spacing )
Cut the thermal sheet to 5 foot tall by 3 foot wide
Back spaced 4 1/2 inches
Whiskers swipped forward 2 inches
15 foot cable length
44 stations
Hisense tv signal strength meter reading
uhf 50% to 60 %
Vhf 35% to 40% ( real stations 7 and 9)
All towers over 55 miles away

Next on the test list 3 ,36 inch reflectors one top bottom center.
ThenTest in some 12 inch reflectors

Last edited by wildwillie; 2018-01-23 at 10:26 PM.
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post #2 of 8 (permalink) Old 2018-01-25, 04:33 PM Thread Starter
Join Date: Jan 2009
Posts: 452
Testing update

Today I took off the big reflector and to test out a vhf reflector rods
So I first check the hisense signal meter on the tv for the 2 vhf stations 9-1 CBC and 2-1 Fox real channels 7 and 9
Both were cutting out unwatchable all uhf that I can recieve signal meter reads were 40 to 50 %

No modelling was done .
This test is not to improve uhf but to increase vhf

So here's some measure meets and rod lenghts
1/2 diameter rods
3 - 36 inch long
2 - 13.5 inch long
4 - 11.5 inch long

The 36 inch rods are placed in this order
One at center back 4.5 inches from phase lines
Top 36 inch rod 21.5 inch above centre , back spacing 3/4 inch
Bottom 36 inch rod 21.5 below center , back spacing 3/4 inch

The 13.5 inch long rods this order
4.5 inches back from phase lines spaced from center top rod 18.5 inches bottom rod 18.5 inches

The 11.5 inch long rods this order
4.5 inches back from phase lines spaced from centre top rod 14.5 inches , bottom rod 14.5 inches
4.5 inches back from phase lines spaced from center top rod 2 3/4 inches, bottom rod 2 3/4 inches

Home made coax cable matching 5 turn inductence coil wrapped ,wired up as a 4 to 1 300 ohm impedance matching. Balun It also works for uhf
VHF station towers over 50 miles away
9-1 real channel 9 34% hisense signal meter reading cristal clear viewing
2-1 real channel 7 40% hisense signal meter reading cristal clear viewing
Some of the uhf stations also showed a 5 to 10% increase on the hisense signal meter.
Test performed inside house antenna 10 feet from ground.
Next to test the GH reflector system placed behind the bow ties

Last edited by wildwillie; 2018-01-25 at 06:20 PM.
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post #3 of 8 (permalink) Old 2018-01-26, 12:05 AM
Join Date: Nov 2008
Location: San Diego, CA
Posts: 3,191
Without a dimensioned Sketch, I don't think I have enough info to construct a 4nec2 model....

Perhaps can you modify one of my 4nec Files, such as the one or the other that I used in fol. HUM4 Model, a JOINTLY OPTIMIZED Hi-VHF + UHF 4-Bay Bowties with either 4 Hi-VHF RRs + 7 UHF RR's....or 8 Hi-VHF RRs + 15 UHF RR''s been quite awhile since I did it, but as I recall the roughly 1:2 RATIO of Hi-VHF to UHF RR's was important to BALANCING the Hi-VHF vs UHF Performance:

Note that in these trial runs, I Constrained each SET of RR's to be SAME Length and Separation [Free Form would help to Flatten the Freq Response].....and I did a total of 16 Optimizations, with 2 to 14 Hi-VHF RRs). Also note that the OPTIMUM Separation between Bowties and UHF RR's was 5.5-in, whereas OPTIMUM for Hi-VHF RR's was about 13-15 inches....which is in agreement with OPTIMUM for individual UHF 4-Bay Bowtie and Hi-VHF 4-Bay Bowie Antennas. [Moving RR's closer to Bowties increases Gain, but at the expanse of Higher SWR + Vice Versa.]

FYI: I also explored the use of Hi-VHF Resonator Loops to improve Hi-VHF Performance of 2-Bay and 4-Bay Antennas. Fol. RLH4 model (w/o Reflector) illustrates the usefulness of this technique. Although I have not yet done any Optimizations with Reflector Rods (or Screen Grid), I'm would expect it would improve not only Gain (by about 3 dB), but (as usual) would also lower the SWR:

Optimized 2-Bay Bowtie with Hi-VHF Resonant Loop RLH2 Models are found towards bottom of fol. Album:

Note that at extreme bottom is an entire Folder of Hi-VHF Resonant Loop models compared, where the OP requested that the designs to fit within his existing 3-ft H x 2-Ft W Metal Framed Picture hanging on the Wall....which turns out was actually much bigger than "Optimum".....
wildwillie likes this.

Antenna Simulations, Overload Calculations, etc:

Last edited by holl_ands; 2018-01-26 at 12:23 AM.
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post #4 of 8 (permalink) Old 2018-01-26, 06:37 PM Thread Starter
Join Date: Jan 2009
Posts: 452
Thanks holl_ands, all I have now is just this iPad , lost my good computer, that I ran the software on, so now I just test with duck tape and electrical conduit. Once I get a antenna performing good from the bad mock ups, then I build to spec, my mock ups are done with ruff measurements , Duck tape works great no wonder " Red Green " loves the stuff lol. Not all DIY people can build to spec and neither can I, but I do get close, want I'm trying to do with the 11.5 inch RR and 13.5 inches RR as impedance adjusters . For were I placed the 36 inches RR.
Then I decided to DIY a coax cable inductor that would cover the vhf and UHF bands as there is not to many places around here now to buy a balun transformer,
The inductor is working really nice configured as a 4:1 coax cable balun, spacing of coils is the key lol
I will get the paper out and draw you up the element and spacing if you want to run it ,just let me know holl_ands
Holl_ands with my setup as it is now I can pull off the back side and picked up 3-1, 5-1 and 61-1 and at night I can pull in 28-1 which is over 75 miles away

Last edited by wildwillie; 2018-01-26 at 07:26 PM. Reason: Wrong measurement size
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post #5 of 8 (permalink) Old 2018-01-26, 07:14 PM Thread Starter
Join Date: Jan 2009
Posts: 452
Don't fall off your chair holl_ands

Here's a picture of the build . DIY with duck tape and a home made inductor for my tv. Viewing lol
The inductor works great and it's made out of coax cable , the coil spacing is the key , to be used with UHF and VHF.
The lowest percentage of signal reading on my hisense signal meter for UHF is 33 % on station 28-1 which is over 75 miles away and can only receive it at night , all other UHF stations holding in the 50% range some hitting 60%
The vhf stations ranging for 45 % peak to 35 %

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post #6 of 8 (permalink) Old 2018-01-28, 02:11 PM Thread Starter
Join Date: Jan 2009
Posts: 452
Today i tested out a wifi antenna connection on one of my RR with a length of 35 3/4 inches
What I did was connect a run of wire from the center RR
To the shielding of my inductor .
Test test test
With this new RR connection the station stopped cutting out.
And no lost of signal strength was shown on the hisense tv signal meter.
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post #7 of 8 (permalink) Old 2018-01-29, 09:38 PM Thread Starter
Join Date: Jan 2009
Posts: 452
Remounted the coax cable balun today . Fits right into the frame design. Drilled 2 holes to feed the connection line out to the phase lines. And one hole out the back of the T to feed the coax threw.
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post #8 of 8 (permalink) Old 2018-01-29, 09:53 PM Thread Starter
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