https://www.instructables.com/HDTV-Multipath-Shield/

I don't believe this is genuine, for a a number of reasons.

Bill

On Wednesday, 5 January 2022 at 18:09:26 UTC, wrightsaerials@aol.com wrote:
> https://www.instructables.com/HDTV-Multipath-Shield/
>
> I don't believe this is genuine, for a a number of reasons.
>
> Bill

Multipath was certainly an issue for analog TV, and a paler shadow image would appear displaced horizontally in the picture.

Not an issue AFAIK with terrestrial digital TV. You can get adjacent channel interference on satellite if you don't have your LNB aligned quite right.

On 05/01/2022 19:03, R. Mark Clayton wrote:
> On Wednesday, 5 January 2022 at 18:09:26 UTC, wrightsaerials@aol.com wrote:
>> https://www.instructables.com/HDTV-Multipath-Shield/
>>
>> I don't believe this is genuine, for a a number of reasons.
>>
>> Bill
> Multipath was certainly an issue for analog TV, and a paler shadow image would appear displaced horizontally in the picture.
>
> Not an issue AFAIK with terrestrial digital TV.
It's certainly not an issue for DVB-T,  but ATSC  is a different kettle
of fish.

For starters, as the web page shows, it has a 'spot' pilot carrier, I
need to read up on what purpose that serves  ?

On 05/01/2022 20:03, Mark Carver wrote:
> On 05/01/2022 19:03, R. Mark Clayton wrote:
>> On Wednesday, 5 January 2022 at 18:09:26 UTC, wrightsaerials@aol.com
>> wrote:
>>> https://www.instructables.com/HDTV-Multipath-Shield/
>>>
>>> I don't believe this is genuine, for a a number of reasons.
>>>
>>> Bill
>> Multipath was certainly an issue for analog TV, and a paler shadow
>> image would appear displaced horizontally in the picture.
>>
>> Not an issue AFAIK with terrestrial digital TV.
> It's certainly not an issue for DVB-T,  but ATSC  is a different kettle
> of fish.
>
> For starters, as the web page shows, it has a 'spot' pilot carrier, I
> need to read up on what purpose that serves  ?
>

Well anyway, here's why I think it's a made-up article.
1. He says that the reflections are caused by "signal bouncing back and
forth between the two buildings" that are either side of the signal
path. Gibberish.
1a. If he is suffering multipath it won't be from those buildings; it
will be from buildings to the side and rear of his location, with the
s/n ratio worsened by the foliage attenuation of the direct signal path.
1b. His screening device couldn't possibly discriminate between a signal
originating from between those buildings and a reflection coming from
one or both of the buildings. The angle is too narrow.
2. The screening box-thing is so close to the aerial that it encroaches
severely on the aerial's capture area. It's about λ/2 but it needs to at
least 2λ. It would de-tune the aerial and lower the gain severely. The
same applies to the dustbin idea.

My guess is he's done this in ignorance and found it didn't work so he's
just made out it has.

Bill

On Thursday, 6 January 2022 at 02:01:05 UTC, wrightsaerials@aol.com wrote:
> On 05/01/2022 20:03, Mark Carver wrote:
> > On 05/01/2022 19:03, R. Mark Clayton wrote:
> >> On Wednesday, 5 January 2022 at 18:09:26 UTC, wrights...@aol.com
> >> wrote:
> >>> https://www.instructables.com/HDTV-Multipath-Shield/
> >>>
> >>> I don't believe this is genuine, for a a number of reasons.
> >>>
> >>> Bill
> >> Multipath was certainly an issue for analog TV, and a paler shadow
> >> image would appear displaced horizontally in the picture.
> >>
> >> Not an issue AFAIK with terrestrial digital TV.
> > It's certainly not an issue for DVB-T, but ATSC is a different kettle
> > of fish.
> >
> > For starters, as the web page shows, it has a 'spot' pilot carrier, I
> > need to read up on what purpose that serves ?
> >
> Well anyway, here's why I think it's a made-up article.
> 1. He says that the reflections are caused by "signal bouncing back and
> forth between the two buildings" that are either side of the signal
> path. Gibberish.
> 1a. If he is suffering multipath it won't be from those buildings; it
> will be from buildings to the side and rear of his location, with the
> s/n ratio worsened by the foliage attenuation of the direct signal path.
> 1b. His screening device couldn't possibly discriminate between a signal
> originating from between those buildings and a reflection coming from
> one or both of the buildings. The angle is too narrow.
> 2. The screening box-thing is so close to the aerial that it encroaches
> severely on the aerial's capture area. It's about λ/2 but it needs to at
> least 2λ. It would de-tune the aerial and lower the gain severely. The
> same applies to the dustbin idea.
>
> My guess is he's done this in ignorance and found it didn't work so he's
> just made out it has.
>
> Bill
+1

On 06/01/2022 02:01, williamwright wrote:
> My guess is he's done this in ignorance and found it didn't work so he's
> just made out it has.

One way it could have worked that I can think of is if the signal is too
strong and this just works as a substitute for an attenuator.

I guess his dustbin cantenna could work with a very simple antenna in
the dustbin. The one in the dustbin does look like it's only two elements.

--
Brian Gregory (in England).

Like I say it can for extremely high frequencies, but in that case the
aerial and its 'can' need to be designed as a unit, not just any thing will
do, unless he has been very lucky in some way.
I've seen mesh cages on the top of receiving stations to stop the
interference from behind, but in no case do they contain the aerial.
Brian

--

This newsgroup posting comes to you directly from...
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Blind user, so no pictures please
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"williamwright" <wrightsaerials@f2s.com> wrote in message
news:j3n0quFisnmU1@mid.individual.net...
> On 05/01/2022 20:03, Mark Carver wrote:
>> On 05/01/2022 19:03, R. Mark Clayton wrote:
>>> On Wednesday, 5 January 2022 at 18:09:26 UTC, wrightsaerials@aol.com
>>> wrote:
>>>> https://www.instructables.com/HDTV-Multipath-Shield/
>>>>
>>>> I don't believe this is genuine, for a a number of reasons.
>>>>
>>>> Bill
>>> Multipath was certainly an issue for analog TV, and a paler shadow image
>>> would appear displaced horizontally in the picture.
>>>
>>> Not an issue AFAIK with terrestrial digital TV.
>> It's certainly not an issue for DVB-T, but ATSC is a different kettle of
>> fish.
>>
>> For starters, as the web page shows, it has a 'spot' pilot carrier, I
>> need to read up on what purpose that serves ?
>>
>
> Well anyway, here's why I think it's a made-up article.
> 1. He says that the reflections are caused by "signal bouncing back and
> forth between the two buildings" that are either side of the signal path.
> Gibberish.
> 1a. If he is suffering multipath it won't be from those buildings; it will
> be from buildings to the side and rear of his location, with the s/n ratio
> worsened by the foliage attenuation of the direct signal path.
> 1b. His screening device couldn't possibly discriminate between a signal
> originating from between those buildings and a reflection coming from one
> or both of the buildings. The angle is too narrow.
> 2. The screening box-thing is so close to the aerial that it encroaches
> severely on the aerial's capture area. It's about ?/2 but it needs to at
> least 2?. It would de-tune the aerial and lower the gain severely. The
> same applies to the dustbin idea.
>
> My guess is he's done this in ignorance and found it didn't work so he's
> just made out it has.
>
> Bill

Actually, if you are only getting ghosting on one analogue channel some very
painstaking fiddling you can often get acceptable results with two aerials
offset and adjusting the phasing cable between them, but its not easy. I did
it as a test here on a severely ghoste relay and it was extremely
sensitive and the attenuation meant you lost S/N as well.
Also if your ghosting is from a tower crane, forget it as every time it
moves it will be different!

I'd like a sure fire way to remove multipath from FM stations myself. That
is almost impossible if you live in Leeds and want to listen to the fm local
station, and often Humberside is stronger. I used to have relatives there.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
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Blind user, so no pictures please
Note this Signature is meaningless.!
"R. Mark Clayton" <notyalckram@gmail.com> wrote in message
news:ec8a04fd-0fb0-4b30-9e9f-c6e8811a4be6n@googlegroups.com...
On Thursday, 6 January 2022 at 02:01:05 UTC, wrightsaerials@aol.com wrote:
> On 05/01/2022 20:03, Mark Carver wrote:
> > On 05/01/2022 19:03, R. Mark Clayton wrote:
> >> On Wednesday, 5 January 2022 at 18:09:26 UTC, wrights...@aol.com
> >> wrote:
> >>> https://www.instructables.com/HDTV-Multipath-Shield/
> >>>
> >>> I don't believe this is genuine, for a a number of reasons.
> >>>
> >>> Bill
> >> Multipath was certainly an issue for analog TV, and a paler shadow
> >> image would appear displaced horizontally in the picture.
> >>
> >> Not an issue AFAIK with terrestrial digital TV.
> > It's certainly not an issue for DVB-T, but ATSC is a different kettle
> > of fish.
> >
> > For starters, as the web page shows, it has a 'spot' pilot carrier, I
> > need to read up on what purpose that serves ?
> >
> Well anyway, here's why I think it's a made-up article.
> 1. He says that the reflections are caused by "signal bouncing back and
> forth between the two buildings" that are either side of the signal
> path. Gibberish.
> 1a. If he is suffering multipath it won't be from those buildings; it
> will be from buildings to the side and rear of his location, with the
> s/n ratio worsened by the foliage attenuation of the direct signal path.
> 1b. His screening device couldn't possibly discriminate between a signal
> originating from between those buildings and a reflection coming from
> one or both of the buildings. The angle is too narrow.
> 2. The screening box-thing is so close to the aerial that it encroaches
> severely on the aerial's capture area. It's about ?/2 but it needs to at
> least 2?. It would de-tune the aerial and lower the gain severely. The
> same applies to the dustbin idea.
>
> My guess is he's done this in ignorance and found it didn't work so he's
> just made out it has.
>
> Bill
+1