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OK... Now that I am going to be up on the roof to install my new high VHF fringe antenna, I figured I should ask another related question...

Do I need a separate antenna for FM broadcast? And if so, what do you recommend, and how do I (or can I) combine it like I am planning on doing with my VHF/UHF using the diplexer?
 

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So this video I linked below was posted online with examples of KRCR-tv 7 & KIXE-tv 9 in the Chico area.
Both stations have VHF & UHF transmitters.

I have noticed the same problem with some UHF stations on very windy days.
I will guess that trees within 300 feet of the UHF Antenna cause this problem. Normally not a problem with a normal breeze, but when the trees forcefully move back & forth in the wind. The same thing happens as seen in this video.
This older video also has an analog UHF channel that shows what tree movement outside does to the picture.
Enjoy.

This is a misinterpretation of what's going on. It's not the wind per se that's causing the problem, it's moving vegetation that's causing the problem. I skimmed the video and didn't see him mention this. He showed blowing trees to show us the wind was blowing and then went on to talk about just the wind. I've seen vegetation cause a problem even in a light breeze. In fact, non-moving vegetation causes signal problems all the time. The problem is just fixed, not varying.

I've found here that LOS isn't always a guarantee of no vegetation issues. If the path barely clears the vegetation, the vegetation can still cause issues.

He doesn't offer any explanation as to how moving air can affect radio waves because it doesn't. If it did then most everyone would have problems all the time.

Chuck
 

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This is a misinterpretation of what's going on. It's not the wind per se that's causing the problem, it's moving vegetation that's causing the problem. I skimmed the video and didn't see him mention this. He showed blowing trees to show us the wind was blowing and then went on to talk about just the wind. I've seen vegetation cause a problem even in a light breeze. In fact, non-moving vegetation causes signal problems all the time. The problem is just fixed, not varying.

I've found here that LOS isn't always a guarantee of no vegetation issues. If the path barely clears the vegetation, the vegetation can still cause issues.

He doesn't offer any explanation as to how moving air can affect radio waves because it doesn't. If it did then most everyone would have problems all the time.

Chuck
In the spring / summer I have seen things get worse because of the "foiliage" of the signal by the NEW growth that attenuates the signals.
And some poor antenna installs, rotors with slop, etc. blowing all over the place causing many degrees of change.
KeithT
 

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Two- UHF 4-Bay Bowties aimed in different directions??
ACTUAL experience please!

I see them selling two phased 4-bay UHF Bowties aimed in different directions?
(see image) https://www.amazon.com/dp/B00KIUDIPG/ref=sr_1_36?


*** My install would be aimed about 24 degrees from each other.
My gut says it would be problematic for multipath from being slightly out of phase.
I don't have anything nearby to reflect, and they are only going to be aimed 24 degrees apart.
(the two main sites, Mt. Toro and Fremont Pk, from Santa Cruz).

Anyone install one of these?
Thanks.
 

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I see them selling two phased 4-bay UHF Bowties aimed in different directions?
(see image) https://www.amazon.com/dp/B00KIUDIPG/ref=sr_1_36?


*** My install would be aimed about 24 degrees from each other.
The problem with this is the pattern maxima are not necessarily in the directions the individual patterns are "aimed", and the pattern can vary with frequency. See patterns for the similarly designed DB8E here:

https://www.antennasdirect.com/cmss_files/attachmentlibrary/Technical Data PDF's/DB8E-TDS.pdf

A 4-bay has a dipole-like front side pattern, i.e. a fairly wide beam. At 24 degrees, I think you'd be better off just to aim a single 4-bay halfway between.

If you need more gain, stack two 4-bays vertically instead of horizontally for the same theoretical gain without narrowing the horizontal beam or introducing side lobes and nulls.
 

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In the spring / summer I have seen things get worse because of the "foiliage" of the signal by the NEW growth that attenuates the signals.
And some poor antenna installs, rotors with slop, etc. blowing all over the place causing many degrees of change.
KeithT
I agree completely but that's a different issue from the wind directly affecting the RF signal in the air which seemed to me what the video was saying.

Chuck
 

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Two- UHF 4-Bay Bowties aimed in different directions??

Yeah, we get this about twice a week. How can I make something work, that basic RF engineering says won't work. But sometimes, it might work. Some of the time. And it's cheap, easy and a shortcut. I've kind of lost patience with this question after the hundredth time, sorry.


You know what does work, for sure, 100% guaranteed? Point two antenna at the two different transmitters, then hang a tuner off each coax feed.
 

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Update on my quest for KRON after the repack... :)

I ordered the Stellar Labs 30-2475 Deep Fringe High VHF Antenna and the Stellar Labs Diplexer... Received it today!!!

Installed it and am able to just barely get KRON... I know signal strength meters probably vary based on the tuner that you are using, but based on my TiVo Roamio tuner, the signal strength peaks at 45/100. Right now it is mostly sitting at 43/100. I get a 95%+ usable reception... Meaning that 5% or less, I get some light pixelation and audio drops...

At first, I installed it two feet underneath my DB4e and I got nothing. Signal strength was 30/100.

I ended up closing the gap and almost mounted it less than a few inches beneath my DB4e. I know it is not ideal, but it was necessary for me to get the height required to pickup any usable signal at all... Doesn't seem to be impacting my UHF reception on any of my channels, so I think I am good.

As you all know, watching a channel with occasional artifacting and audio drop outs is pretty frustrating, so I am returning the 30-2475 and have ordered the longer/larger 30-2476 (yeah, yeah...here's where you tell me you told me so!!! LOL)...

I am hoping that the fact that I have nearly a 100% usable signal with the 2475, that the 2476 will give me the little bit of added reception quality to actually get to a 100% usable signal... Will update you when I swap out the antennas!

Here's a photo of my current set-up with the 2475. As you can see, it is right underneath. And in fact, if you look closely, the rear of the 2475 actually overlaps a bit with the DB4e... Like I said, I needed the height, or I get a completely unusable signal... :(

 

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Update on my quest for KRON after the repack... :)

I ordered the Stellar Labs 30-2475 Deep Fringe High VHF Antenna and the Stellar Labs Diplexer... Received it today!!!

Installed it and am able to just barely get KRON... I know signal strength meters probably vary based on the tuner that you are using, but based on my TiVo Roamio tuner, the signal strength peaks at 45/100. Right now it is mostly sitting at 43/100. I get a 95%+ usable reception... Meaning that 5% or less, I get some light pixelation and audio drops...

I have a TiVo Roamio also. The "Antenna Signal Strength" meter is not a signal strength meter. It is a Signal Quality meter. Actually you have no idea how strong KRON actually is. My guess is that KRON is plenty strong but you have a lot of multipath. Changing Signal Quality when moving the antenna position a bit would tend to confirm this. About all you can do is try the antenna in different positions until you find one that's better.

For whatever reason, the highest Signal Quality I've seen is 72/100. The TiVo meter in the Diagnostic screen is also a Signal Quality meter. Whey they didn't include a real signal strength meter is beyond me. It would really be helpful.

Chuck
 

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I have a TiVo Roamio also. The "Antenna Signal Strength" meter is not a signal strength meter. It is a Signal Quality meter. Actually you have no idea how strong KRON actually is. My guess is that KRON is plenty strong but you have a lot of multipath. Changing Signal Quality when moving the antenna position a bit would tend to confirm this. About all you can do is try the antenna in different positions until you find one that's better.

For whatever reason, the highest Signal Quality I've seen is 72/100. The TiVo meter in the Diagnostic screen is also a Signal Quality meter. Whey they didn't include a real signal strength meter is beyond me. It would really be helpful.

Chuck
How interesting! For some reason, this sounds so familiar, and I think you may have shared that with me a few years ago on this thread... But obviously if I was informed years ago, I forgot!

The tuner on the Roamio seems to perform differently than my TCL and LG tuners (and I guess the morale to this story is that all tuners are not created equal). As an example, KOFY channel 20 looks fantastic on my TCL tuner, yet it is constantly and predictably pixelated with audio drop outs on my Roamio. Both are connected to the same antenna feed.

I am really hopeful that I can improve the signal quality of KRON with the new longer, larger 30-2476 antenna... I am academically concerned about how close I have to mount my Stellar Labs antenna to my DB4e, but I don't see an alternative to be honest. And I guess I shouldn't worry about the academics of this, and should be more focused on the functional aspects... If it works, it works, right? :)

I also find trying to tune/aim two antennas on one mast frustratingly difficult... Here is what I ended up doing:
  • Took my mast down and layed it on the rooftop
  • Mounted Stellar Labs VHF antenna below DB4e (24 inches below) - Didn't worry about the DB4e aim at this point
  • Hand mounted mast back in place without tightening any brackets and rotated to get best signal
  • Discovered that KRON was not coming in at all. Almost as though I didn't even add the VHF antenna at all.
  • Moved mast to another location to clear the treetops. No change.
  • Raised/hoisted mast manually by 2-3 feet and rotated around. KRON signal found (but not a good picture)
  • Went back to original location at chimney and manually raised by 2-3 feet. Same behavior. KRON found, not a good picture.
  • Took mast down and layed on rooftop and moved VHF antenna within a couple of inches from DB4e, some elements on rear of Stellar Labs overlapping with my DB4e. Replaced mast by hand mounting and discovered that I am getting KRON signal. Rotated and discovered that the strongest TiVo signal quality was 42-45 and noted direction.
  • Took mast back down and started to adjust the relative direction between my DB4e and my 30-2475... Re-hand-mounted and adjusted to maximize VHF, and then roughly tested UHF channels.
  • Rinse and repeat taking the mast up and down. For the most part, I aimed to maximize my VHF KRON signal, and pretty much accepted the fact that I was not going to be able to optimize my UHF aim. My UHF aim was "roughly right" and fortunately it is not a directional antenna, so it worked for me. Not sure what I would have done if I had to optimize two highly directional antennas on the same mast!!!
Long process...which I will have to repeat again when I receive my Stellar Labs 30-2476.

Thanks for taking this "journey" with me... Again, I hope that the 30-2476 makes a difference. Spec-wise, it is supposed to have an increase of 1-2db gain... I am not technical enough to know whether that is a big or an insignificant difference... I will absolutely report back!
 

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Update on my quest for KRON after the repack... :)

I ordered the Stellar Labs 30-2475 Deep Fringe High VHF Antenna and the Stellar Labs Diplexer... Received it today!!!

Installed it and am able to just barely get KRON... I know signal strength meters probably vary based on the tuner that you are using, but based on my TiVo Roamio tuner, the signal strength peaks at 45/100. Right now it is mostly sitting at 43/100. I get a 95%+ usable reception... Meaning that 5% or less, I get some light pixelation and audio drops...

It is possible you're multipathing yourself with sub-optimal antenna location, although that is just a guess. I know suggestions on this forum that involve money and or effort are not always well received, but I'm going to throw this out there anyway given the poor results from the first low effort low $$ attempt (no offense, you're entitled to try. Your $$ and effort.)


Consider installing 2" X 8' X 1/8" wall thickness sections of antenna mast from Penninger radio, and a mast joiner clamp (I went for overkill with the MC-200-12 mast clamp) get your antenna up above interactions with your roof, and allow some distance to the UHF antenna above. This will cost more than your antenna, but won't require guy wires, as I'm pretty sure you wouldn't like that either.


A sturdy mast will allow 10' of unsupported height, which may well address your problem. Of course this may require modification to your strap installation hardware, which likely won't accept 2" mast. VHF's longer wavelength generates multipath at greater distances. VHF channel 7 is 109" at 1/2 wavelength, although it may be sufficient to distance the antennna from objects by more than 1/4 wave.
 

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It is possible you're multipathing yourself with sub-optimal antenna location, although that is just a guess. I know suggestions on this forum that involve money and or effort are not always well received, but I'm going to throw this out there anyway given the poor results from the first low effort low $$ attempt (no offense, you're entitled to try. Your $$ and effort.)


Consider installing 2" X 8' X 1/8" wall thickness sections of antenna mast from Penninger radio, and a mast joiner clamp (I went for overkill with the MC-200-12 mast clamp) get your antenna up above interactions with your roof, and allow some distance to the UHF antenna above. This will cost more than your antenna, but won't require guy wires, as I'm pretty sure you wouldn't like that either.


A sturdy mast will allow 10' of unsupported height, which may well address your problem. Of course this may require modification to your strap installation hardware, which likely won't accept 2" mast. VHF's longer wavelength generates multipath at greater distances. VHF channel 7 is 109" at 1/2 wavelength, although it may be sufficient to distance the antennna from objects by more than 1/4 wave.
Wow! That's a pretty cool solution... I had no idea that there were options for 2" masts and mast-joiners... So this is what you have implemented at your home? Is it reasonably easy to find chimney mounts and antenna mounts that attach to a 2" mast?

At this point, I already have the 30-2476 on order, and it is in transit... I am going to see what that does for me... And as I mentioned, I don't feel great about the academics and purity of my implementation, but I need to get over my OCD tendencies and focus on the functional aspect of my solution... As long as I can turn on my television and access glitch-free content, I think I am good to go!

And I do appreciate visibility to the choices available, regardless of the effort or cost involved... Good to know what is out there!
 

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Wow! That's a pretty cool solution... I had no idea that there were options for 2" masts and mast-joiners... So this is what you have implemented at your home? Is it reasonably easy to find chimney mounts and antenna mounts that attach to a 2" mast?

At this point, I already have the 30-2476 on order, and it is in transit... I am going to see what that does for me... And as I mentioned, I don't feel great about the academics and purity of my implementation, but I need to get over my OCD tendencies and focus on the functional aspect of my solution... As long as I can turn on my television and access glitch-free content, I think I am good to go!

And I do appreciate visibility to the choices available, regardless of the effort or cost involved... Good to know what is out there!

The mast parts are in transit, I already have two UHF (SF and Fremont) and one full-band VHF antenna (SF) waiting in boxes. My VHF antenna will be 54" above the chimney, with the closest UHF (Fremont) antenna 54" above, and the top UHF antenna (SF) at 12' above the chimney. Hopefully I don't experience crippling VHF multipath, or too much unsupported mast height.


I hope it works for you, although Calaveras may not have been wrong regarding quality not strength. Can you try a tuner with a real signal strength meter as a point of information?
 

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The mast parts are in transit, I already have two UHF (SF and Fremont) and one full-band VHF antenna (SF) waiting in boxes. My VHF antenna will be 54" above the chimney, with the closest UHF (Fremont) antenna 54" above, and the top UHF antenna (SF) at 12' above the chimney. Hopefully I don't experience crippling VHF multipath, or too much unsupported mast height.


I hope it works for you, although Calaveras may not have been wrong regarding quality not strength. Can you try a tuner with a real signal strength meter as a point of information?
I can't see how you could go wrong here... Looks like a primo solution...

What are you trying to achieve with your set-up, and what are the challenges that have brought you to this particular solution? It sounds like you were pretty happy with your current set-up... Did the repack present new challenges that require the horsepower you are putting into your new solution?

Honestly, my current solution gets me everything I need, and most of what I want...even without introducing the new high-VHF antenna... KRON is a want, not a need... With my current UHF only set up I get every single channel I need, which are the major networks...and exposure to more than my share of extra wants and nice-to-haves...

KRON is more than a nice-to-have, but is something that I could live without... So the effort and investment I am making is really just to add KRON back to my channel line-up... That's it... :)
 

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I can't see how you could go wrong here... Looks like a primo solution...

What are you trying to achieve with your set-up, and what are the challenges that have brought you to this particular solution? It sounds like you were pretty happy with your current set-up... Did the repack present new challenges that require the horsepower you are putting into your new solution?

The current UHF-only setup receives every possible channel from my home in S. San Jose, even the weakest ones like KRCB on Mt. St. Helena before the repack, without a rotor or switch, media server compatible. The repack makes VHF a necessity. Or a want. My perspective on that is if I'm going to do it, I'm going to get everything, with no dropouts.



Since I'm doing it again, I figured I may as well get the repack-optimized UHF antennae designed for 470 - 600MHz as well. My plan is to use good hardware and never touch it again, except for tuner replacement to ATSC 3.0. I'm even using stainless steel cable ties instead of nylon.
 

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Since I'm doing it again, I figured I may as well get the repack-optimized UHF antennae designed for 470 - 600MHz as well.

I hope you're going to give us a detailed report on the XB16A. I don't know anyone else using one. Was shipping from England expensive?

Chuck
 

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I hope you're going to give us a detailed report on the XB16A. I don't know anyone else using one. Was shipping from England expensive?

I bought two antennae, XB10 for Fremont 16 miles away, and XB16 for SF and San Bruno 48 miles distant. Paid about $90 for shipping. Shipping an antenna in the US isn't inexpensive either, getting that NOS Winegard HD5030 full-band VHF here was costly as well. I'm determined to do it right, and be done with. I only wish I had known enough to do it this way when I put up my current setup a few years back, but the repack was barely a jingle in the FCC's pocketbook at that time.


Given that I receive everything UHF today, the only differences I would see with the narrow band antennae would be hook up to my current antennae with a spectrum analyzer, look for cellular signals between 600 and 900 MHz, take screenshots, then perform the same exercise with my new narrowband antennae. Or I could measure the VSWR, which should be improved.


These are real figures of merit. I may even have an F to N adapter to get me into the spectrum analyzer, although with a 75 to 50 ohm mismatch. I have access to such equipment, as I'm an electrical engineer. However, I do this stuff all the time, so it isn't that interesting as a hobby. It's kind of like work, and I have plenty of work to do. Really what I want is good results, and I won't need to make a bunch of time-consuming measurements to get there. Probably I'll spend the time doing the assembly and installation. It may be all I do is look at some weak stations on the tuner, record the values, then look at them with the new antenna.


Sorry I'm not a better sport. Not unlike the shoemaker's kids and the mechanic's car. :(
 

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SHF1 (Stephen Fischer) status

This morning I received the sad news that Stephen passed away in hospice last Friday morning. He was not a Covid-19 victim.
 
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