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Discussion Starter · #1 ·
I don't know why just hasn't been attempted before. I had some degree of success if you believe signal meters and the Spectrum analyzer.

I took two Televes DAT BOSS LR Mix antennas and made one. I remember watching the Solid Signal video of Stuart putting one together and how hard it was and how heavy it was and how it would take two people to install it. This is a one-hander. It's big. But not heavy, slightly awkward.

But first , I decided just to add the front end sections from one DAT to the other:
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Here is "Mod 1":
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The donor and the cannibal:

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This is "Mod 2" I had to do some strengthening, I added the front brace and some other minor enhancements:

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It was definitely an improvement:
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For those of you that know me, I'm never satisfied with "good enough"

So I endeavored to take the rest of the pieces off of the donor antenna and add them to my new "DAT XLR":
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My helper, just helping me he picked up on some grade life skills, hacksawing, drilling and hammering without destroying!



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Test results in the next post
 

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Discussion Starter · #2 · (Edited)
After 3 days of anticipation I climbed the ladder, The antenna is big, but light. So, getting it up on the mast, there's a little bit of the challenge only because there was an intermittent strong Breeze. As soon as I would lift the antenna up to start putting the clamps on the breeze would come.

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I usually do everything after work. Saturday was no exception. But I got it Up Before Sunset:
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So, I ran some scans with the RTL SDR. I know this doesn't tell the whole story, but it definitely performs better then the test baseline subject, the stock factory DAT BOSS LR :

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These tests could be flawed for a number of reasons:

#1) the fact that one antenna is on a different mast and the aim may not be the same.

#2) as seen in the photo there isn't much space between the "163 XG" and the "DAT XLR" You guys know more than I do, but I believe they are too close to each other.

#3) The AGC preamps on both antennas are active. However, I did several overlapping test on each antenna and compared them. The tests were consistent. The spectrograms are consistent and mirror each other for the most part.


Here's an afternoon Screenshot:
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How about some boring Channel information? I'm glad you asked...:cool:!

I'll start with one of the more difficult channels. I do most of my testing aimed at Milwaukee, simply because my Chicago view is corrupted by trees. Also, Milwaukee is at least 10 more miles distant so the challenges are more realistic.

I'm lucky to get in RF 16. WYTU-LD. 12.7 dB signal margin on my RabbitEars.Info report.

RF 16:
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RF 27:
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RF 28:
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RF28:
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I had to skip RF30, the screenshot didn't "take".

RF31:
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RF32:
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RF35:
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Looking for opinions or comments.
Worth it or not?
Could design be improved?
Upper and lower boom angles, could increasing or reducing the angles help?
What effect would a larger reflector have?

Thanks !
 

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Discussion Starter · #4 · (Edited)
You need an intervention.:)
Buy a crank up or tilting mast before you hurt yourself.
You're right, an intervention might help. But, I've been diagnosed with A.D.D. (Antenna Distraction Disorder). I first noticed it in 1999 when I purchased a VU190XR. Seems like that wasn't good enough, so I went to RadioShack and bought a VU210XR. Laying in bed Sunday mornings and rotating my antenna getting stations from a few hundred miles away seem to verify Radio Shack's claims that this was a 200 plus mile antenna. 😉

However, OTA programming seem to be very boring and I ended up with DirecTV and later Comcast cable. In fact, I was able to watch all three at any given time for over a year. All my friends were impressed that the best picture still came in over the antenna.

My A.D.D.went into remission and I felt a stir during the digital transition, however I kept it repressed. However, in 2016 I began to have A.D.D. symptoms again. The cable bill out started increasing without warning. But this time it was worse. If it now progressed into A.D.D.H.D. (Antenna Distraction Disorder High Definition). This can only be relieved with ganging / stacking / combining antennas or hacking different antenna designs.

20200920_154240.jpg
 

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well, I am totally impressed. I will have to to put things in context ( your rabbit ears ). You must be real far out...

I have what appears to be a smaller (later) version of LR MIX DATBOSS. I need greater VHF from it. Specifically
VHF- 12
 

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Discussion Starter · #6 ·
well, I am totally impressed. I will have to to put things in context ( your rabbit ears ). You must be real far out...

I have what appears to be a smaller (later) version of LR MIX DATBOSS. I need greater VHF from it. Specifically
VHF- 12
Yeah, the VHF is not up to a dedicated Long Yagi VHF antenna, still, I do get Strong VHF from Chicago (40 miles) and 70% from Milwaukee (50 miles) so, it does just fine for me.
 

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! am about 60 miles from the towers, all in one spot southwest. I receive those (excepting v-12)

This antenna brought happiness because it worked so well, easy to handle, and also was less than 1/2 cost of alternative fringe antenna system ....and thereby slowed the progression of my ADD.

I wonder how to increase VHF capacity on this antenna.
 

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I noticed that the reflectors on the back have not been modified. Could it make a difference if they were doubled in size?
 

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but how does all this apply to the "triple boom"...or is it single boom?

Additional Elements:
The single or folded dipole is of limited gain and is not very directional. To increase the gain, "parasitic" elements can be added. Unlike the active dipole, these are made from single length of narrower gauge aluminum and do not need insulating from the tubular aluminum antenna boom.
Reflectors: A reflector is a "parasitic" element because it is not electrically connected to the dipole or downlead/feeder; it is a length of conductor, usually aluminum, of length around 5% longer than the dipole, mounted behind the dipole. If the reflector-dipole spacing is set at 0.15 to 0.25 electrical wavelengths, then the potential difference induced in it lags that developed across the dipole by 180 degrees, which causes a lagging current to flow in the director (see next paragraph). Thus, if the signal travels through the dipole to the reflector and reaches the dipole once more in phase with the signal on the dipole (180 + 180 = 360 degrees behind or 1 whole wavelength behind) and hence the two signals add, giving a stronger signal at the receiver. If the signal is behind the antenna, the radiations at the dipole and from the reflector subtract, giving a weaker signal at the receiver. Hence, the antenna is more directional.
Directors: Further increases in gain and directionality can be achieved if an additional parasitic element or "director" is added, 5% shorter than the dipole and the 0.1 to 0.15 wavelengths in front of it. When the dipole radiates, a potential difference is induced in the director and a leading current flows in it. It re-radiates and again adds to or subtracts from the radiations at the dipole, increasing or decreasing the signal going to the receiver, depending on the direction in which the antenna is pointing relative to the transmitter. Further directors can be added, but as the number of directors is increased, so the contribution made by the director decreases and almost levels out after 12 or so directors.



Reflectors and Directors


vhf 12 207 mhz = 1.4 meters
 

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Discussion Starter · #11 ·
Thanks for your interest in this project. I knew going in I wouldn't be able to get a lot of help on this because I don't think anybody I know is ever hacked a Televes antenna of any kind. I have seen them ganged/stacked...

I'm looking for advice or input even if someone hates it.

I have enough material to add on to my reflector. It would be cool to start there.
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That's a great idea. I'm pretty sure I'd have to put a lot more length on it.
Not necessarily. A few VHF-High directors could be interspersed between the UHF directors. They might have to be dual-mode to work for both bands, like on some Winegard antennas.
 

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Discussion Starter · #14 ·
I noticed that the reflectors on the back have not been modified. Could it make a difference if they were doubled in size?
Some of the hacks on other antennas I have seen have shown some improvement, usually on the order of .5dB. I am wonder how much to enlarge and how much is too much?

Also, I have seen where others have used other materials like 1/2x1/2 Garden mesh. AD uses what looks like wire fencing on the 91XG.

Adding mesh, that could be easy...

91 XG:

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hat
 

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Discussion Starter · #15 ·
Not necessarily. A few VHF-High directors could be interspersed between the UHF directors. They might have to be dual-mode to work for both bands, like on some Winegard antennas.
Rabbit, Very interesting. I guess it would be another conversation to ask how dual band directors work, but I am all ears!

.... and what are the little "wings" on the dual band directors?
 

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Rabbit, Very interesting. I guess it would be another conversation to ask how dual band directors work, but I am all ears!

.... and what are the little "wings" on the dual band directors?
I don't have a complete understanding of the dual band director, but Winegard wouldn't have done it unless it would increase the VHF-High gain without reducing the UHF gain.

If you just insert a VHF-High director with the UHF directors, it could act as a reflector for UHF and reduce the UHF gain. But, if you somehow make a dual-band director that is useful for VHF and UHF, that could work without having to make the boom longer.

It is my understanding that the whole dual-band director is used as a director for VHF-High, and the two small end sections are directors for UHF.

My guess is that the little "wings" are broad band 1/4 wave stubs that isolate the two small end sections from the larger middle section. A 1/4 wave stub that is open at the far end is a short at the lower end where it is attached. This property of a 1/4 wave stub allows it to isolate the small end sections so that they can function as directors for UHF.

You can see 1/4 wave stubs used in the original RCA ANT751 antenna. They short out UHF signals received by the VHF section of the antenna so that they don't interfere with the UHF signals received by the UHF section of the antenna. This is, in effect, a simplified UVSJ.

RCA ANT751stubsRev3.jpg


This concept is seen in a patent by John Winegard:

Winegard UHF Tetrapole2.jpg


But I could be wrong.
 

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I don't have a complete understanding of the dual band director, but Winegard wouldn't have done it unless it would increase the VHF-High gain without reducing the UHF gain.
Multiband yagis with interlaced elements for ham radio on the HF bands and VHF/UHF bands have been around for a long time. I don't see why it wouldn't work for TV too.
 

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Discussion Starter · #19 ·
Multiband yagis with interlaced elements for ham radio on the HF bands and VHF/UHF bands have been around for a long time. I don't see why it wouldn't work for TV too.
Do you mean similar to the combo antennas that have two different width directors? I the HD8200 U has that, I believe.
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