Jump to content

Alps 0.3Db High Gain Lnb


MattCinderey

Recommended Posts

That's the one!

I've just moved my dish myself. The UBC engineers decided it was OK to point it directly at a tree. I should have checked their work but was out when they did the install. Doh!

Matt.

You cannot just replace it without proper tuning. If you have a dreambox and know the sattelite then you could tune the signal.

You said "UBC engineers", but I suppose you mean the not so skilled technicians UBC send to your place.:lol:

Link to comment
Share on other sites

Don't waste your money in swapping out your TrueVision KU band LNB on the 75cm Red or Gray disk. The advertising hype about sgnificant differences in signal reception/noise reduction between a 0.2db, 0.3db, 0.4db, 0.6db LNB is all hype from a real world signal gain standpoint. Now what can make a BIG difference is properly aligning/optimizing the alignment of your dish, getting a bigger dish, and/or mounting a KU band LNB on a C-band dish via use of a combo/integrated C/KU band LNB.

Heck, when I was still using TrueVisions satellite dish DSTV system (I'm now on TrueVisions cable CATV & internet) I loosened the dish's horizontal and vertical positioning bolts, set the TrueVisions set-top box to the menu setting that shows Signal Value (i.e., strength) and did very minor up/down and left/right dish adjustments and gained 7 db signal strength. I even loosened the LNB holding bracket/bolts and moved the LNB forward and backward a little and twisted it from its 4:30 on the clock position a little....the back and forth movement made no gain difference since the bracket allows very little movement and the LNB rotation maybe made about 0.2 db difference but it was at practically the same position for this small 0.1db gain. The required rotation position for the LNB in Thailand is at the 4:30 position. By 4:30 I mean when you are looking straight at the dish and thinking of it as a clock, the LNB output connector is set to the 4:30 position.

Now, with that 7db gain, I was hoping that would eliminate my rainfade here in Bangkok...it did "help" to reduce it, but did not get rid of it. Later on I got a combo C-Band & KU Band 11300Mhz LNB and replaced my standard C-Band only LNB on my 5.5ft C-band dish (which I still have/use). The larger dish made a significant improvement in KU band signal strength. But I would still lose TrueVision in a heavy rain; compared to losing the signal in a light to medium storm or even sometimes when it ain't raining at your place yet/just heavy rain clouds/the storm is coming your way.

But if you just have to try another LNB on your TrueVisions dish, visit or order one from 9Sats in Bangkok. It will be a heck of lot cheaper....heck, many satellite system installers get their parts at 9Sats. Here's their website link to their KU band LNBs....be sure to have Google translate turned on...and you can click a few more links to narrow down to Universal LNBs or 11300Mhz only LNBs like TrueVisions uses. Link

By the way, the TrueVisions LNB that came with my TrueVisions DSTV setup was a 0.3db LNB but with the TrueVisions label on it. 0.3db LNB nowdays is pretty much the standard.

P.S. Quite frankly it surprises the way and where many of the small KU band type dishes (like TrueVisions, DTV, etc) are mounted in Thailand that they can pickup a signal in good weather, much less in rain. I mean they are pointing directly at other buildings, trees, etc., but in many cases in the city they ain't go no choice in mounting location and definitely can't move a building, roadway bridge, electric pole, etc., which is obstructing the line of sight to the satellite.

Edited by Pib
Link to comment
Share on other sites

  • 2 weeks later...

I would suggest a larger dish, rather than a different LNB, with a marginally better gain figure.

A swop from a 70cm dish to 1m will give you a gain of 3db (2x as much).

You will need to find a local supplier to fit it.

Link to comment
Share on other sites

Hmm... Or do I go hardcore and go for the 150cm! It will be rainy season here soon in Samui.

Don't be surprised if you still don't have some rain-fade, because in heavy rain/heavy rain clouds KU band frequencies sometimes just can't get through/the KU band signal is greatly attenuated. So, even with a 150cm dish (or even a 500cm dish) you probably wouldn't pickup a signal unless the satellite is really pumping out the power with a focused beam to punch through the clouds/rain. But it seems most satellites opt for a wider coverage area at lower power like the Thaicom5 satellite which transmits the TrueVisions signal.

From looking at the Jonsa web site (Link) regarding offset KU-band dish gain at 12.45GHz here is the gain for the various sizes would get you:

60cm: 36.5db

75cm: 38.5db (same size as a TrueVisions red/gray dish)

90cm: 39.5db

120cm: 42.1db

150cm: 43.8db

Link to comment
Share on other sites

Thanks for that. Very interested. I went with the 120cm dish. Can't wait to install it and set it up properly.

Good luck....be sure it get aligned directly at the satellite...and be sure to do the final alignment on a low power channel and align for the highest Signal Quality level if possible with your set-top box. Many people think that once I align the dish to maximum Signal Strength that they have made the best alignment. Wrong.

And after you have the highest Quality Level on that low power channel if you go back to a high power channel like Ch 3 or 7 you should see that the Signal Strength and Signal Quality are unchanged. And even if they are changed just a little, like maybe a tad lower, you are already have more than enough Signal Power & Signal Quality on those channels. Now if your setup box only has a Signal Strength/Signal Value indicator like a standard issue TrueVisions set-top box, but not Signal Quality indicator also, then all you can do is align/peak the dish vertically and horizontally for max Signal Strength.

Just be sure you get spot-on alignment with the satellite and being just a little misaligned can cost you many db in gain...enough loss of gain to effectively negate the gain of the larger 120cm dish. Real- world example: years back TrueVisions installed my 75cm dish system. I had rain-fade problems. Later on I adjusted the dish myself and gained approx 7 db just by very slight adjustments....if I remember right I got 5 db gain from correct horizontal alignment and another 2 db from correct vertical alignment. Now, still had rain-fade after getting that additional 7 db in gain, but I got the rain-fade less often but still too much to my liking. But rain-fade is all in my past now as I now have TrueVisions "cable" and my C-band system (5.5ft dish) don't experience rain-fade.

Link to comment
Share on other sites

Pib, thanks again for the reply. Which channel would you use for the weakest for tuning purposes? I can see myself spending hours outside tweaking the dish, darn my OCD. LOL.

Oh, I can't say now as I don't have TrueVisions satellite TV anymore. After the initial alignment, just scan through the channels to see which ones give you lower power levels and use one of those.

Link to comment
Share on other sites

Out of curiosity perhaps, but you may like to know that the Ku-band, which is in the 10.95-14.5 GHz, is the preferred frequency band for naval fire control systems. Some companies use the Ka-band. X-band and C-band are better used for surveillance less good for target tracking.

Before I retired I worked as a marketing manager for the Swedish Defence Contractor SAAB and this is the CEROS 200 tracking radar.

Link to comment
Share on other sites

KU band is indeed popular. I expect the fire control KU band radar system in the video was pumping out some high power and only looking out maybe a couple hundred miles and using military grade electronics...compared to the TrueVisions setup which is receiving a moderate level signal using a $50 dish & LNB from a geosynchronous satellite around 26,000 miles up in space.

Now if we could get TrueVisions to team up with your former company maybe TrueVisions could improve their signal and eliminate rain-fade for its Thailand customers. ;)

Link to comment
Share on other sites

KU band is indeed popular. I expect the fire control KU band radar system in the video was pumping out some high power and only looking out maybe a couple hundred miles and using military grade electronics...compared to the TrueVisions setup which is receiving a moderate level signal using a $50 dish & LNB from a geosynchronous satellite around 26,000 miles up in space.

Now if we could get TrueVisions to team up with your former company maybe TrueVisions could improve their signal and eliminate rain-fade for its Thailand customers. ;)

Yes, the power is quite large but the tracking distance for gun fire control do actually exceed thirty kilometres, rain has very little influence on the distance, with the CEROS 200 tracking radar and for CWI (missile tracking) much more than that. Modern tracking radars are using TWT (Traveling Wave Tube), whereas spin-tune magnetrons were common in the past.

The ship shown on the video is one of the Australian / New Zealand frigate class "ANZAC". There are eight built for Australia and two for New Zealand.

This just to show that Ku-band can be used successfully also in rain.

Edited by stgrhe
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.



×
×
  • Create New...