quality drop... or signal? wi-max ect. I'm lost

Discussions specifically related to master c band satellite television.
JKL
TVRO Member
TVRO Member
Articles: 0
Posts: 7
Joined: Thu May 16, 2019 4:10 am
Has thanked: 2 times

Re: quality drop... or signal? wi-max ect. I'm lost

Post by JKL » Sun Aug 11, 2019 9:47 pm

LAWRENCE006 wrote:
Sat Aug 10, 2019 10:47 am
How would you build a shoud today around the dish
Haha, yeah right!. Tho, if you take a look at some broadcasters dishs, youll see tiny shrouds not that big.
This is a apropos picture but funny. Looks a Ham radio way of doing things.

Tags:

JKL
TVRO Member
TVRO Member
Articles: 0
Posts: 7
Joined: Thu May 16, 2019 4:10 am
Has thanked: 2 times

Re: quality drop... or signal? wi-max ect. I'm lost

Post by JKL » Sun Aug 11, 2019 10:03 pm

dishcrank wrote:
Sat Aug 10, 2019 1:12 pm
Adding a shroud will add a lot of weight to your dish and increase the wind resistance (...) It might just turn out to be your neighbor's microwave oven. :lol:
Actually, I found a super light way of doing this with sheet metal (the one with a white side) screwed to the edgeof the dish. A foot deep maybe.
Some pruning has to be done first... see photo. :-) :grin:

But seriously good joke. I even wonder if it's not a stupid methodology :lol:

JKL
TVRO Member
TVRO Member
Articles: 0
Posts: 7
Joined: Thu May 16, 2019 4:10 am
Has thanked: 2 times

Re: quality drop... or signal? wi-max ect. I'm lost

Post by JKL » Sun Aug 11, 2019 10:13 pm

fatso wrote:
Sat Aug 10, 2019 7:31 am
The purpose of the shroud is to reflect all off-boresight signals away from the dish (...) Below is a picture of a shrouded dish I found in an old satellite magazine.
Thanks, a lot good points and well summarized. :thanks

Your pic makes a good contrast with mine :lol:

All produce a picture with the added light shroud eventually. 8-)

JKL
TVRO Member
TVRO Member
Articles: 0
Posts: 7
Joined: Thu May 16, 2019 4:10 am
Has thanked: 2 times

Re: quality drop... or signal? wi-max ect. I'm lost

Post by JKL » Sun Aug 11, 2019 10:55 pm

fatso wrote:
Sat Aug 10, 2019 7:31 am
...to reduce sparklies on analog tv signals...
This exactly my problem NOW with my Trx-2000 receiver slaved to my PC (inverse of what we all did with DVB to 4DTV). :toofunny

C-Span has some sparkles with my set-up. :innocent:

User avatar
tek2000
TVRO Salesman / Sponsor
TVRO Salesman / Sponsor
Articles: 0
Posts: 248
Joined: Fri Jun 20, 2014 4:38 am
Location: Canada
Been thanked: 2 times
Contact:

Re: quality drop... or signal? wi-max ect. I'm lost

Post by tek2000 » Mon Aug 12, 2019 7:52 am

All,

Some things you can try to combat TI:


1. The problem is not always TI related. Therefore, check your dish alignment and make sure you can track the satellite arc. Adjust the skew, elevation and azimuth settings one at a time and check to see if performance improves.

2. Change the illumination pattern of your feed. A feed which over-illuminates the parabola will detect more TI because of the larger side lobes. A feed which under-illuminates will have significantly smaller side lobes and therefore detect less TI. To under-illuminate your dish, simply move the scalar ring further up the throat of the LNB. You can also remove the scalar ring altogether for extreme under-illumination.

3. Try using an anti-TI feed. For small amounts of TI outside the C-band range of frequencies, these bandpass filters work quite well. If the TI occurs inside the range of C-band frequencies (e.g. future 5G), you will likely need a notch filter. These are expensive and will also wipe out any transponder at the center frequency of the notch filter. However, they will restore the rest of the C-band frequency range. The company Microwave Filters makes them, but expect to pay a small fortune to purchase one.

4. Add motorized skew or motorized declination control (or both) to your dish. When you change the skew or declination of your dish, you are effectively rotating the radiation plot. This slight rotation can cause the TI power to fall on a null point between two side lobes, or at a point where lower amounts of TI power will be detected. I can confirm to you that this trick works remarkably well. In the one direction of rotation the TI noise increases, but in the other direction, it attenuates. The only downside is that your C/N ratio will drop a bit because the satellite signal is being detected off-axis. For example, when detecting an on-axis satellite signal, you may have a C/N of 12 dB but significant amounts of TI make reception impossible. After rotating the feed or changing the declination, the new C/N may only be 10 dB but the transponder locks fine.

5. Change the location of your dish. Try installing behind a structure like a building which will shield your antenna from TI. If this isn't possible, consider digging out a bunker and installing the dish partially below ground. You will also get the added advantage of protection from high winds. Finally, consider building wire-mesh TI screens or a Faraday cage to protect your dish from strong levels of TI.

6. Lastly, consider upgrading to a larger dish. Larger dishes have smaller side lobes and therefore "see" much less TI. Upgrading to a larger dish is equivalent to adding a shroud around a smaller dish, with the added advantage of more gain. That's why I'm not a big fan of shrouds.


TI is mostly a big city problem. If you are a TV or radio station and your 10' dish gets hit with a ton of 5G TI one of these days, you may consider upgrading to a 12', 13.5' or 15'. Below, a fully motorized Az-El-Skew antenna for TV/Radio stations, cable companies, military and astronomy applications, etc. Only available in sizes 12' and up.



commercial_mesh_20.JPG
Last edited by tek2000 on Mon Aug 12, 2019 8:05 am, edited 1 time in total.
Owner
http://www.tek2000.com
#1 Supplier of TVRO Satellite Equipment in North America

(I am not on this forum often and don't check forum PMs, so please email me for faster service)

User avatar
tek2000
TVRO Salesman / Sponsor
TVRO Salesman / Sponsor
Articles: 0
Posts: 248
Joined: Fri Jun 20, 2014 4:38 am
Location: Canada
Been thanked: 2 times
Contact:

Re: quality drop... or signal? wi-max ect. I'm lost

Post by tek2000 » Mon Aug 12, 2019 8:03 am

JKLALP wrote:
Fri Aug 09, 2019 6:50 pm
The only place I could place the BUD tripod (quadrupod should I say) is near by the road, underneath electricity utility and communication cables (around 90w from the dish) and among trees and leafs. It sees from 55w (high trees) to 133w (too low).

Your problem is most likely those power lines. The 60 Hz power is leaking into your cable. Try grounding your dish, coax and related hardware. Buy a good quality AC plug filter for your receiver. It will help a lot.
Owner
http://www.tek2000.com
#1 Supplier of TVRO Satellite Equipment in North America

(I am not on this forum often and don't check forum PMs, so please email me for faster service)

JKLALP
New Member
New Member
Articles: 0
Posts: 2
Joined: Thu May 16, 2019 5:13 pm

Re: quality drop... or signal? wi-max ect. I'm lost

Post by JKLALP » Tue Aug 20, 2019 10:45 pm

Just a follow-up here. :bigsmile

The utility company's "pruning" contractant passed by last week and the problem is now barely noticeable most of the time. :biggrin

Smell like obvious grounding issues. :innocent:

As seen on the previous photo, the ground is kinda sand(ish). I' gonna put a real 8 foot ground rod for my BUD. :dancer:

:thanks for all the good reads :watchingtv

Post Reply

Return to “C Band Satellite”