1R2D Yagi (Flat & Transparent) BAS-5122 470-700 MHz - Canadian TV, Computing and Home Theatre Forums

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post #1 of 15 (permalink) Old 2018-04-14, 01:37 PM Thread Starter
 
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1R2D Yagi (Flat & Transparent) BAS-5122 470-700 MHz

SWR <1.5: 470-700 MHz
SWR <2.0: 450-710 MHz
Gain: 6...7.5 dBi
Substrate: h=1 mm, e=~3 (measured experimentally)





https://ypylypenko.livejournal.com/25972.html
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post #2 of 15 (permalink) Old 2018-04-14, 02:58 PM
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Thank you for showing us a Loop Fed Yagi Array for TV reception, Yurii. We are seeing the horizontal coplanar loop as the driven element more frequently, as a result of the work by G0KSC.
https://www.google.com/search?q=loop...iw=911&bih=345

https://www.gigaparts.com/loop-fed-y...lfa-6m4el.html

Coplanar LFA Yagi Antenna

If you can not measure it, you can not improve it.
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post #3 of 15 (permalink) Old 2018-04-14, 03:31 PM
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I'm curious as to F/B & F/R Ratio performance (and Beamwidth)....seems to be comparable to "Silver Sensor" 7-El LPDA types (see 4nec2 Analysis for Zenith and Terk HDTVi)....and not quite as good as my 4-El FLAT LPDA [YOWZA!!!!]:
https://imageevent.com/holl_ands/zigzaglpa/uhflpda

==================================
BTW: I did an Optimization for a UHF 8-El. Flat-Loop-Fed (FLF) Yagi [it's actually a standard Folded Dipole that has been rotated so it is "Coplanar" with other Elements]:
https://imageevent.com/holl_ands/yag...8flfyagi300ohm
Note I changed the name to prevent confusion with whatever claims "LFA" and "OWA" Antennas might make....

And a Single Channel (Ch22) 9-El FLF Yagi which turned out to have extraordinarily HIGH (40+ dB) F/B & F/R Ratios:
https://imageevent.com/holl_ands/yag...9flfyagi300ohm

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #4 of 15 (permalink) Old 2018-04-14, 04:14 PM Thread Starter
 
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If one change this vibrator to folded dipole (same inner/outer dimensions but solid surface) - Yagi will still work, but SWR will be always >1.5
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post #5 of 15 (permalink) Old 2018-04-14, 04:20 PM
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I already have a simple antenna that fits in any size window.
My only question is in yours, what is the wall wart and usb cable for?
One suggestion, design for the future and rescale it for under 600MHz.

DB4E/VHF Yagi rotor FM Bandstop ap-8700 preamp 4way split LG lcd.
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post #6 of 15 (permalink) Old 2018-04-14, 04:22 PM Thread Starter
 
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Follow LJ link - more photo
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post #7 of 15 (permalink) Old 2018-04-14, 04:24 PM
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Can't you just explain?
I don't wish to visit another site with their own ads, so on...

DB4E/VHF Yagi rotor FM Bandstop ap-8700 preamp 4way split LG lcd.
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post #8 of 15 (permalink) Old 2018-04-14, 04:26 PM Thread Starter
 
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LNA in black box
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post #9 of 15 (permalink) Old 2018-04-14, 04:32 PM
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ahh, shouldn't need an LNA for such a short coax cable.

I don't see the benefit of it being flat on that substrate.
it's not conserving any space. Looks too flimsy.
My homemade antenna is nikiml's biquad, and fits in a window.

Agree with Hollands, better off with something solid and proven like silver sensor
if you are looking for an antenna to sit on top of something

DB4E/VHF Yagi rotor FM Bandstop ap-8700 preamp 4way split LG lcd.
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post #10 of 15 (permalink) Old 2018-04-14, 04:38 PM Thread Starter
 
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Quote:
ahh, shouldn't need an LNA for such a short coax cable.
it's not for North America market.
95% users in target market use extreme cheap chinese TV-tuners (~$10..$15) with measured Nf=7...12 dB (design flows (simplifications) are identified and well-known). Also coax splitters are popular to use with 2+ TV sets.

Quote:
I don't see the benefit of it being flat on that subsrate.
no benefit, only [negligible] electrical penalty for design purpose
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post #11 of 15 (permalink) Old 2018-04-14, 05:46 PM
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If you read the research, the benefits of a horizontal coplanar loop for the DE can be: flatter gain curve, lower SWR, and better F/B and F/R for rejection of signals in other directions, which is why it is called a low noise antenna.

Having the preamp at the antenna does more than compensate for distribution losses, it lowers the system noise figure because the tuner NF becomes irrelevant since it is then buried in the amplified noise floor.

If you can not measure it, you can not improve it.
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post #12 of 15 (permalink) Old 2018-04-14, 05:49 PM
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rabbit, what I mean is I don't see any benefit compared to other designs that do the same thing. It's not saving you any space being on that substrate. It still takes up the same amount of space.
Thanks for the suggestion, but I will stick to my outdoor antennas and my home made antenna that actually fits in a window,

DB4E/VHF Yagi rotor FM Bandstop ap-8700 preamp 4way split LG lcd.
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post #13 of 15 (permalink) Old 2018-04-14, 06:52 PM
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You are not required to use the antenna that Yurii has shown us.

It is an interesting unconventional design that is not intended to conserve space, but to demonstrate the use of a flat coplanar loop used as a driven element in a yagi antenna.

The main advantage of a loop fed array is that it is better than a conventional yagi at rejecting interference from other directions. Hams find it useful when working weak signal DX. I would imagine that it would have the same advantage for TV DXers and to reject multipath reflections.

It would certainly help reject co-channel and adjacent channel interference from another direction. We will probably be seeing more of that as a result of UHF Repack.

If your mind is closed to new ideas that don't agree with your old ideas, how can you learn anything new?

I didn't see any ads when I clicked on the link to Yurii's journal, but I did see the circuit board for the LNA.
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If you can not measure it, you can not improve it.
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Last edited by rabbit73; 2018-04-14 at 07:48 PM.
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post #14 of 15 (permalink) Old 2018-04-15, 07:20 AM
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Trust me, I don't plan on using the antenna.
I don't need any lessons, nor have I asked for any.
Thanks..

DB4E/VHF Yagi rotor FM Bandstop ap-8700 preamp 4way split LG lcd.
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post #15 of 15 (permalink) Old 2018-04-15, 12:48 PM
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Quote:
Originally Posted by majortom View Post
I don't need any lessons, nor have I asked for any.
YOU questioned what I said:
Quote:
Originally Posted by majortom View Post
rabbit, what I mean is I don't see any benefit compared to other designs that do the same thing.
THAT gives me the right to answer.

If you can not measure it, you can not improve it.
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