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videobruce 10-Feb-2021 5:39 PM

1 Attachment(s)
rabbit73;
To answer your questions;
Siglent SSA 3032X
'True' north (it's easier, the house is N-S, E-W within 1 degree which makes the job very easy ;) ).

The reference to 355 degrees is due to the offset from 330 degrees necessary being the only way I can receive the Toronto stations (RF 17-20) due to the 'swamping' effect from RF 16 even with the additional 20db attenuation from my traps. Doing so drops the offending station level over 10db making the difference.

Quote:

At the present time, are you able to receive 17 that is adjacent a much stronger 16? That would seem impossible for a TV tuner to handle.
Yes it will be, especially with a crappy tuner; aka TiVo. :mad:
Quote:

Is there a filter design that would work better?
I was originally going to go with Tin Lee, but due to poor communication (on their part) and cost, I went with PAR Electronics which I've done business before. I use to do business with C & E in East Syracuse NY (which were partners with Tin Lee), but they went out of business unfortunately.

See the attachment. Tuned for 15/16 and 31/32
.

videobruce 10-Feb-2021 5:56 PM

Tower Guy;
Yes, it can get VERY expensive depending on how many cavities you want. Horizontal 'stacking' antennas is out of the question. Too much wind resistance and additional weight on the rotor. And a $400 Amateur rotor with a brake is out also. ;)

rabbit73 10-Feb-2021 9:36 PM

1 Attachment(s)
Thank you for your reply
Quote:

Originally Posted by videobruce (Post 63476)
rabbit73;
To answer your questions;
Siglent SSA 3032X

9 kHz to 3.2 GHz, very nice
Quote:

The reference to 355 degrees is due to the offset from 330 degrees necessary being the only way I can receive the Toronto stations (RF 17-20) due to the 'swamping' effect from RF 16 even with the additional 20db attenuation from my traps. Doing so drops the offending station level over 10db making the difference.
So, with traps and the adjustment of aim, 17 is possible; excellent!

It looks like the slope on the high side of 16 was adjusted to be as steep as possible to protect 17.

http://forum.tvfool.com/attachment.p...1&d=1613002844

videobruce 10-Feb-2021 10:03 PM

Possible, depending on conditions.
Yes, to protect RF 17 as much as possible which is not easy to achieve.

Correction on CHCH. That isn't available here thanks to the FCC and the CRTC. :mad: That should be WBNF, which is 40 or so miles closer.

rabbit73 11-Feb-2021 12:27 AM

Quote:

Originally Posted by videobruce (Post 63479)
Possible, depending on conditions.
Yes, to protect RF 17 as much as possible which is not easy to achieve.

Correction on CHCH. That isn't available here thanks to the FCC and the CRTC. :mad: That should be WBNF 40 or so miles closer.

Sorry about that. I missed the co-channel problem. Corrected image in post above.

On this forum, I make images that will show in a post no wider than 750 pixels.

welkin 4-Mar-2021 4:38 PM

Is this ATSC 3.0 compatable?

videobruce 8-Mar-2021 2:17 PM

Post #4 and #7 have been extensively updated.

welkin 8-Mar-2021 9:26 PM

Maybe I'm missing it, but I don't see any information in post 4 or 7 about ATSC 3.0 compatibility. Is the avent x ATSC 3.0 compatible?

videobruce 8-Mar-2021 9:42 PM

You weren't missing a thing. That post was a general announcement, nothing to do with your question.
I don't have an answer to it since when I had this device , there were no ATSC 3 stations on the air in my markets, nor do I have any ATSC 3 tuners even if they were. ;)

tripelo 9-Mar-2021 7:06 PM

1 Attachment(s)
Quote:

Originally Posted by videobruce (Post 63503)
Post #4 and #7 have been extensively updated.

Sorry about your experience with the Avant-X. Just few minutes ago, posted a couple of comments, inquiring about your Avant-X unit.

Likely, you know this, put it here for others benefit:

A DTV station produces splatter outside the normal ~6 MHz bandwith in both upper and lower adjacent channels.

This splatter appears as noise to a receiver that is trying to demodulate the adjacent channel signal.
If the combination of noise (environmental, thermal, other interference plus the adjacent splatter)
reduces the signal-to-noise ratio to less than about 15 dB then signal cannot be decoded.

In the above case, no amount of frequency rejection of the undesired channel can recover the desired signal.

The FCC sets limits on the splatter:

From:

ATSC Recommended Practice:
Transmission Measurement and Compliance for
Digital Television
Document A/64B, 26 May 2008

http://forum.tvfool.com/attachment.p...1&d=1615315891

As shown in the image the splatter begins at about 36 dB below the flat portion of the DTV channel.

That adjacent splatter is caused by intermodulation distortion (IMD) in the transmitter chain.

Pretty sure many stations perform somewhat better that that shown in the graph,
but it is a tough problem for transmitter chain designers.

------------------------

In addition, adjacent splatter can be generated in the TV receiving circuits.

Mainly occurs when signal is very strong.

.


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