Lindsay UHF antenna - Canadian TV, Computing and Home Theatre Forums

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post #1 of 18 (permalink) Old 2017-10-17, 01:56 AM Thread Starter
 
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Lindsay UHF antenna

Hey: Guys.

Ok, I scored another interesting item from Ebay.

It's 2 commercial log periodic uhf antennas made by, Lindsay Antennas.

I'm not sure what part of the uhf band they cover but here are the model
numbers on them. 6LPU66 & I6LPU the longest elements on both are 9" long
and the shortest ones are 3.5" long.

They come with about 6' of RG6 coax on both.

They are really heavy, made of aluminum that is about 1.5" x 1.5"

I also got 3 new Lindsay power supplies, model # LSPS they are marked 24v dc
and have two F connectors marked to antenna & rf, as well as rf out.

Anybody have any info on these items ?

I don't know why I bought them as I most likely can made use of these
monster antennas for home use.

I paid $60.00 USD for everything plus $60.00 USD for shipping.

Any info would be great or if anyone thinks they may want them, let me know.
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post #2 of 18 (permalink) Old 2017-10-17, 05:46 AM
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Can you tell whether they are Yagi or LPDA type Antennas??? And how many Elements??? Photos???

I presume that they are probably LPDAs, which would be more consistent with 2.6:1 ratio between Longest and Shortest Elements...UHF Band Yagi's tend to have a significantly narrower ratio. Using LPCAD34, I did some quick Trial & Error choices for the Lowest and Highest Band Freqs for assumed Tau=0.93 and Optimum Sigma=0.17 until the design matched Longest/Shortest Dimensions, resulting in 14-Element Pair LPDAs, providing 9 dBi Gain. These are Ballpark numbers...depends on actual implementation. [If you provide DETAILED Dimensions, I can plug into my Universal 4nec2 Files.]

IF you mean that the OVERALL Width of the Elements [Tip-To-Tip] varies between 9.0 and 3.5-in, then it works out to be about 640-1280 MHz Antenna (Well above current UHF TV Band.

Alternatively, IF you mean that Elements vary between 9.0 and 3.5-in as Measured from the CENTERLINE, then it works out to be about 320-640 MHz Antenna....rolling off on the high end of the current UHF Band. [Actual Roll-off would probably be even worse since LPDA naturally rolls off on the high end.

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #3 of 18 (permalink) Old 2017-10-17, 01:03 PM Thread Starter
 
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Hi: Hollands

I will take some pics & post them if I can figure out how too again.

Alternately do you have a email I can send the pic too as I
can figure that out for sure.

I don't think they are yagi as they are fed directly with a 6' length of 75 ohm
coax and the upper & lower boom are insulated from one another.

If you type log periodic uhf tv antenna on Google pics they look just like
those but much heavier construction.

Length of elements from where they bolt to the boom to the tip.
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post #4 of 18 (permalink) Old 2017-10-17, 05:44 PM
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Help Thread re Posting Photos using your Album on Digitalhome [limited resolution as I recall]:
How to create a photo album for use on the Digital Forum

So, it is for sure an LPDA designed for (at least part of) UHF Band.
If you provide Detailed Dimensions I can model it to see what the upper frequency response REALLY looks like....

I prefer to keep info exchange visible to the rest of the community on this forum....
But just in case you have problems, I'll provide my personal eMail address via PM...

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #5 of 18 (permalink) Old 2017-10-19, 01:50 AM Thread Starter
 
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I just wanted to see if you got the pics of the Lindsay uhf tv antenna I sent.

I'm sorry that I'm not too good with the uploading stuff.

Bruce.
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post #6 of 18 (permalink) Old 2017-10-19, 09:51 AM
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They probably cover up to the 800MHz band.

DMX 68' tower, HyGain HAM 5 rotator, Antennas Direct DB8e & C5, Channel Master 7777 preamp, Siemens surge protection. TiVo Roamio DVR
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post #7 of 18 (permalink) Old 2017-10-19, 01:44 PM Thread Starter
 
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Hi: Jase88

Not sure what these cover.

The element lengths are per side, other words 9" for the longest element
on the upper then 9" on the lower.

So I'm guessing that since antennas like the CM4221 have 7.5 " V elements
and are good from ch 14 - 69 that 9" elements would cover the low uhf well
and the 3.5" one would be good for high uhf & at a minimum would act as
directors for the longer elements.

On the label there is a model # and a spot for frequency but al it
says is 66 . So I don't know if that means channel 66 !
If so then they are useless for tv unless I slip longer aluminum over
all the elements to shift the frequency coverage lower.

Bruce.
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post #8 of 18 (permalink) Old 2017-10-19, 01:57 PM
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Lindsay Antennas produced antennas for head ends such as those used for cable systems. The company (or at least the antenna division) was sold to Wade. Wade continued to produce their channel specific and narrow band yagi antennas. Log periodic antennas, by design, are wide band antennas so it's fairly safe to assume that this antenna will cover the entire UHF band from 14 to 69 and probably a little more.

I built a UHF log periodic in the late 1960s from a design in an electronics magazine. The design was fairly simple and easy to make with some copper wire and a soldering iron. The longest element was about 6". Unfortunately, the plans are long lost but a log periodic design might make an interesting DIY antenna for the forum.
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post #9 of 18 (permalink) Old 2017-10-19, 05:00 PM
 
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LPDA is fairly simple design, but... not easy to mantain SWR<2.
First, CAD using MoM cannot correctly model impedances (Pattern & Gain are correct), because it is heavily dependent on boom construction.

I have 2 models of LPDA UHF-TV antennas with low gain (5-7 dBi) but good SWR on 470...860 MHz






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post #10 of 18 (permalink) Old 2017-10-19, 05:07 PM
 
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post #11 of 18 (permalink) Old 2017-10-20, 01:00 AM Thread Starter
 
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Thanks for all the input guys.

If anyone thinks they may have a use for these two antennas,
please let me know. I kinda bought them on impulse now I
have no real use for them.

Bruce.
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post #12 of 18 (permalink) Old 2017-10-20, 07:19 AM
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Yes I got the photos you sent. It's a Log-Yagi with rear half being a Dual-Boom LPDA and front half being a set of Yagi Directors. And isn't it missing one or more Elements???

It would help if you could add THREE MORE photos (Overlapping showing Rear, Middle and Front), shot mostly from ABOVE, but offset a bit to show the 3-D Structures. I especially need to see more detail around the Balun Feedpoint. Since it is NOT a pure LPDA, the LPCAD34 runs are no longer applicable.

We also need a LIST of (X-Coordinate) Measurements for the placement of Elements along the Boom [Center of Rod].
And a LIST of (Y-Coordinate) Measurements for Direction (+/- Y-Coordinate) and LENGTH of each Element Rod.
For the Forward Yagi Directors, this can be a simple Tip-to-Tip Measurement [or Boom Centerline to Tip].
However, for each of the LPDA (Half) Elements, we need the Length of the Rod, as well as how much the SHORT End extends beyond the Centerline of the Boom [Rods attach to the TOP of the Boom].
Also need to know Rod Diameters and Boom Dimensions.

Soonish, I'll post your photos to a new Album on my Antenna Analysis Website, so we can all see them....

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands

Last edited by holl_ands; 2017-10-20 at 07:41 AM.
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post #13 of 18 (permalink) Old 2017-10-20, 01:58 PM Thread Starter
 
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Hi: Hollands.

I will take more pics & send them to your email.

There are no elements missing. There is an extra support boom on each antenna which
I removed to show the antenna without it in the way.

There is no balun feed point as the 75 ohm coax enters the boom near the longest
element then through that boom to the other end of the boom near the shortest
element where it connects internally to the upper & lower sections of the booms
for a 75 ohm imp.

I will try to take more pics with measurements too.

Thanks for all you help & I hope someone reading this can actually make use
of these antennas & the Lindsay power supplies as I can't see mounting these
heavy guys on my tower.

Bruce.
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post #14 of 18 (permalink) Old 2017-10-20, 06:37 PM
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Lindsay UHF Log-Yagi pictures thus far....I'll post more then I get them from DXING.Bruce....
It looks BIG next to SUV...actually "only" 86-in = 7' 2" long and 18-in Wide:
https://imageevent.com/holl_ands/log...i6lpu66logyagi
NOTE: Keep clicking on Album images [3 times] until you see the original 3 to 4 MB Hi-Rez Image. [NOT fol. 1024x768]

Even though some Elements maybe hidden behind others, I still think it's MISSING some [readily fixable].


Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands

Last edited by holl_ands; 2017-10-20 at 06:52 PM.
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post #15 of 18 (permalink) Old 2017-10-21, 03:14 PM Thread Starter
 
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I send Hollands additional pics of the Lindsay Log Periodic uhf antenna.

No elements are missing, In the pics there is a measuring tape beside
most pics to see lengths of elements & boom.

Note these is an additional boom which I removed to take pics, I think it
is for supports when mounting on a tower. It the same length at the main
boom with the same dimensions.
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