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TVI

 

My KIO Hex is up at 60 Ft and works great. Tower is approx. 20 Ft. behind my shack. No TVI ?problems when running 100 Watts, BUT WHEN RUNNING 500W and up and pointing North ?(basically right over my shack),TV blacks out completely, this happens ONLY ON 20 M !
If I rotate antenna to East/West or South no TVI.
I am on Optic Cable for TV.
I tried a Choke/Balun Mix 43 as well Mix 31 with no improvement.
I also have Toroid beads on Coax at Hex up top.
I purchased 20 snap on 43 mix which is on every cable behind TV, and on Coax right behind my rig.
My previous beam was a Six Element Wilson Tri Bander and when running 1KW no TVI ?whatsoever.
Does anyone have a comment?
73
de VA7LP
Lars
 

?
Try to isolate the problem to a "through the air" or "on a wire problem."? If the affected TV has OTA capability, attach an OTA antenna, enable OTA, select a channel, orient the antenna North, and transmit on 20m at 500 watts or higher to see if the same "blacked out" problem occurs.? By feeding the TV with an OTA signal, your provider signal is eliminated.
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Do any other electronic devices in the house exhibit problems when you transmit at high power on 20m?
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If the problem is isolated to RF on the house AC wiring, you can plug an AC line conditioner into the AC outlet supplies power to the affected TV.
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Did you put RFI suppression on the AC power line to the ONT and the AC power line to the router?? Most ONT's are powered with wall warts that are susceptible to RFI on the AC power and through the air if located in the near field of a high power directional signal.
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Does the ONT have a battery backup unit attached and enabled?? If so, disconnect the battery backup unit and see if the problem still occurs.? The ONT will operate without the battery backup unit enabled.? There have been TVI problems reported related to RFI on the ONT battery backup unit.
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What is the make and model of your TV? Some TV brands and models don't comply with FCC standards and are susceptible to problems related to RF through the air.? If you have another TV (preferably different make and model) that can be relocated to the spot occupied by the affected TV, try it to see if it exhibits the same problem during transmission.
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Is the provider streaming signal to the affected TV delivered via CAT-6 ethernet cable connected to the router or via WiFi?
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If the feed is via WiFi, have you monitored the WiFi signal characteristics when transmitting on 20m?? There are a number of WiFi monitoring APPs available for Android, IOS, and Windows.? Some of the APPs provide advanced diagnostic features such as signal-to-noise ratio, etc.
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If you are a DIYer, you could make a relatively inexpensive RF signal strength monitor to check the RF field strength in the vicinity of your affected TV.
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Fred, NC4FB
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Thank You Fred
73
de VA7LP
Lars
 

Greetings,

First the fact that this only occurs when pointing in one direction, pretty much means it is the intended radiated path that is causing the issue, rather then feed cable currents.

It is probably something in the TV connections, be sure to add ferrites to all the TV/cable-box cables including power and audio as RF will find any way in it can! :-)? I know you said every cable, so if you can loop through the core rather than just pass through you will get 4x the impedance, so do that if at all possible. 14MHz often is not easily killed with type 43 with a single turn.? Also look at the orientation and even the length of the TVcables, maybe you were 'lucky' enough to create a good 20m antenna with how they are run through the house!

The oddity here is having no problem with the higher gain/higher power setup.? This begs the question, is there some issue with the 20m hex elements such as a poor connection that misbehaves at higher power levels?? Is the 500W transmitted by the same 1kW? amplifier, if not maybe it has different? harmonic or spurious emissions?

? ? very good luck & 73,

????? ? Colin,? W1DJR.










1a.?
TVI
From:?Lars Pedersen
Date: Mon, 17 Mar 2025 17:38:44 PDT

My KIO Hex is up at 60 Ft and works great. Tower is approx. 20 Ft. behind my shack. No TVI ?problems when running 100 Watts, BUT WHEN RUNNING 500W and up and pointing North ?(basically right over my shack),TV blacks out completely, this happens ONLY ON 20 M !
If I rotate antenna to East/West or South no TVI.
I am on Optic Cable for TV.
I tried a Choke/Balun Mix 43 as well Mix 31 with no improvement.
I also have Toroid beads on Coax at Hex up top.
I purchased 20 snap on 43 mix which is on every cable behind TV, and on Coax right behind my rig.
My previous beam was a Six Element Wilson Tri Bander and when running 1KW no TVI ?whatsoever.
Does anyone have a comment?
73
de VA7LP
 

This is not a sarcastic comment, hi hi: In a television world now defined by either cable-TV (protected by the insulated coax), internet streaming, or digital HDTV, I honestly didn't realize that TVI was still a problem anymore. I remember back in the early 1970s when my Dad and I were first licensed, we hooked up our HW-101 into an unsightly HF vertical on the roof and were subsequently blamed for every TV problem in our neighborhood — some of it deserved and some of it because they now had something new and tall to blame. At least those days are mostly over I think!
73, Randy K7RAN
 

Randy, that reminds me of the time I was putting together a small beam on a couple of sawhorses in the backyard when my neighbor walked over and asked me what I was doing. I was honest and told him.
?
"Oh, that's what has been messing up my TV for the past month!" he told me. Well, I had been on the air on a dipole for years with no complaints, and I had not yet put RF into that beam, so I explained it to him and offered to take a look at his TV to see what might be going on. He never took me up on the offer nor did he complain once I got the antenna up and in use daily. And remained friendly...
?
73,
?
Don N4KC
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?
 

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Back in UK have a 11m with SSB and use to knock all the TV’s and phones on the block, no cable back then and only ran like 10w, much better these days. 1kw and nobody’s complains?


VA3AQB ???
Alan

On Apr 12, 2025, at 17:01, Don N4KC <don@...> wrote:

?
Randy, that reminds me of the time I was putting together a small beam on a couple of sawhorses in the backyard when my neighbor walked over and asked me what I was doing. I was honest and told him.
?
"Oh, that's what has been messing up my TV for the past month!" he told me. Well, I had been on the air on a dipole for years with no complaints, and I had not yet put RF into that beam, so I explained it to him and offered to take a look at his TV to see what might be going on. He never took me up on the offer nor did he complain once I got the antenna up and in use daily. And remained friendly...
?
73,
?
Don N4KC
?
?
 

Funny!

Some 15 years ago I ran 800w in to 4 yagis (22dBd) on 70cm.? Moonrise was due east, past the houses.? Also ran 1kW on 6m and 15dBd gain, pointing all over.? The antennas were in the front yard.

Never had any complaints.? Hooray for cable TV

Cliff K6CLS


On April 12, 2025 1:54:25 PM PDT, "Randy K7RAN via groups.io" <padawer@...> wrote:
This is not a sarcastic comment, hi hi: In a television world now defined by either cable-TV (protected by the insulated coax), internet streaming, or digital HDTV, I honestly didn't realize that TVI was still a problem anymore. I remember back in the early 1970s when my Dad and I were first licensed, we hooked up our HW-101 into an unsightly HF vertical on the roof and were subsequently blamed for every TV problem in our neighborhood — some of it deserved and some of it because they now had something new and tall to blame. At least those days are mostly over I think!
73, Randy K7RAN
 

Gentlemen?
Thank You for your very informative as well as humorous comments!
Greatly Appreciated?
Lars VA7LP
 

I didnt become a ham until 2017, I remember hearing about people blaming hams for interferrence.? ?I do remember bunny ears and old heavy tvs from the 80s and 90s

Douglas V


On Sat, Apr 12, 2025, 13:54 Randy K7RAN via <padawer=[email protected]> wrote:
This is not a sarcastic comment, hi hi: In a television world now defined by either cable-TV (protected by the insulated coax), internet streaming, or digital HDTV, I honestly didn't realize that TVI was still a problem anymore. I remember back in the early 1970s when my Dad and I were first licensed, we hooked up our HW-101 into an unsightly HF vertical on the roof and were subsequently blamed for every TV problem in our neighborhood — some of it deserved and some of it because they now had something new and tall to blame. At least those days are mostly over I think!
73, Randy K7RAN
 

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No kidding! When i was a novice on 40 meter cw, some goon in my apartment building tore down my dipole antenna without even trying to talk to me first. The superintendent found it in the incinerator. JS6TMW ex- K2RDP



On Apr 13, 2025, at 13:49, Douglas V Amateur Radio and More via groups.io <Douglasvamateurradioandmore@...> wrote:

?
I didnt become a ham until 2017, I remember hearing about people blaming hams for interferrence.? ?I do remember bunny ears and old heavy tvs from the 80s and 90s

Douglas V

On Sat, Apr 12, 2025, 13:54 Randy K7RAN via <padawer=[email protected]> wrote:
This is not a sarcastic comment, hi hi: In a television world now defined by either cable-TV (protected by the insulated coax), internet streaming, or digital HDTV, I honestly didn't realize that TVI was still a problem anymore. I remember back in the early 1970s when my Dad and I were first licensed, we hooked up our HW-101 into an unsightly HF vertical on the roof and were subsequently blamed for every TV problem in our neighborhood — some of it deserved and some of it because they now had something new and tall to blame. At least those days are mostly over I think!
73, Randy K7RAN

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