What the... OK, this is stupid...

[Vipersan]

As suspected CJ ..from a techies perspective ...it did look like an agc issue ..
Try a different image on the box ..keeping your channel list if thats possible..
If that doesn't correct it ..the receivers hardware is at fault ..
..and most likely the tuner..(maybe you could borrow one to test first ) ...which can be replaced easily if its pnp..
good luck
VS

 

[Captain Jack]

I posted on a dedicated Vu+ forum and the general consensus seems to be to fit a variable attenuator as the signal is overloading the tuner. The explanation for the other receiver working as designed is the "less sensitive" tuner in that - but I am not convinced.

 

[digi247]

I dont think the Tuners are that sensitive above average maybe but not the best, They are exactly the same as what are used in the Ultimo and i got shut of it due to the tuner sensitivity.

 

[Vipersan]

I posted on a dedicated Vu+ forum and the general consensus seems to be to fit a variable attenuator as the signal is overloading the tuner. The explanation for the other receiver working as designed is the "less sensitive" tuner in that - but I am not convinced.

only my opinion CJ ...but thats a cop out ..
Its either a design flaw in the VU ...or there is a hardware or software issue which hasn't been resolved ..
Firmware producers ..if they are aware of this issue ..should be able to write in a user menu which gives the operator control of the agc ..at the very least.
If its a one off ..only affecting your box ...then this would point to a fault in the hardware/tuner.
rgds
VS

 

[sonnetpete]

I posted on a dedicated Vu+ forum and the general consensus seems to be to fit a variable attenuator as the signal is overloading the tuner. The explanation for the other receiver working as designed is the "less sensitive" tuner in that - but I am not convinced.

Neither am I...if it were the case there would be a lot more complaints from other users viewing strong satellites with larger than average dishes. I think that the tuners are above average in sensitivity, in fact my VU+ is second only to my DrHD in that respect. Maybe the tuners vary slightly and CJ's is better than others but I'm inclined to believe his AGC has somehow either been disabled or is faulty.

 

[Vipersan]

Here is a typical block diagram to show the way agc works in not only a satellite receiver ..but any type of receiver..
I've coloured the relevant area in blue..
The stronger the signal the higher the control voltage generated ..this is then fed back to the first stage of signal amplification ..and used to reduce the gain ..
Its a basic neccessity in ALL receivers ..
If its not functioning as designed ..the results are what you are experiencing ..
Either Software contol is inadequate ..or the receiver/tuner design is flawed...or indeed faulty.
To say you need to reduce the signal entering the receiver ..is passing the buck.
rgds
VS

 

[Captain Jack]

I am going to email WOS and see what they say...

 

[sonnetpete]

As another example, my Dr.HD is (in my opinion) more sensitive than the VU+, it's hooked up to my 1.2M motorised dish plus a Black Ultra and copes with very strong signals with aplomb. I can't see how you can argue that because of tuner sensitivity you need to attenuate your signal, surely that's why AGC is implemented in the design?

 

[lanab]

In the old analog days it was very common that signal overloaded on the new sats as everyone had 1.8m dishes or larger, never seen this in digital age to be honest, first time here...

 

[strs65]

As another example, my Dr.HD is (in my opinion) more sensitive than the VU+, it's hooked up to my 1.2M motorised dish plus a Black Ultra and copes with very strong signals with aplomb. I can't see how you can argue that because of tuner sensitivity you need to attenuate your signal, surely that's why AGC is implemented in the design?

My F15 was the decoder that had the most problems with the Black Ultra at 19.2E here (I believe most of those problems stem from the quite strong analogue transponders, which in a few days will cease to exist). So I guess it is more a case by case situation. I recently bought a Vu+ Uno, but didn't test it with the Black Ultra (F15 and the TBS6925 is indeed more sensitive than the Uno).

 

[Captain Jack]

Welp, sent a few emails to WOS and they tried to be very helpful but the most they could do is offer a tuner swap. As it's more hassle/expensive to send the tuner rather than get an attenuator, I left it.

Came home and put a Technomate 0.1dB LNB on that I had lying about. Immediately, the signal on strong sats shot up to their normal levels. NHK world was ready 77% and BBC1 West on 1N was reading 95% (previously 74%).

Sadly though, weaker satellites did suffer. Weaker channels on 5E didn't go above 38% no matter what I did with the LNB and C+ HD channels on 1W weren't even locking. Put the Black Ultra back on and the same 5E channels went to 45% and C+ HD on 1W was locked and steady at 59% (54% needed for lock on those).

So... not sure whether I should try a different LNB with similar gain figures as the Ultra without overloading the tuner on the strong sats or a simple attenuator. Looking on eBay, item 170823333195 seems to be the same as 380389276933 but the latter is obviously more expensive. Is it worth having the more expensive one? Or should I get the Smart Oxid LNB for £10 instead? Any ideas on the performance on these?

 

[sonnetpete]

CJ, would it be 28°E, 19°E and 13°E that you watch the most of those you are having the trouble with? Could you not alter their position in the Uno setup? I.E. make 19°, 18.7°? etc. Perhaps it would be enough to knock the edge off the signal.

 

[strs65]

....

Sadly though, weaker satellites did suffer. Weaker channels on 5E didn't go above 38% no matter what I did with the LNB and C+ HD channels on 1W weren't even locking. Put the Black Ultra back on and the same 5E channels went to 45% and C+ HD on 1W was locked and steady at 59% (54% needed for lock on those).

So... not sure whether I should try a different LNB with similar gain figures as the Ultra without overloading the tuner on the strong sats or a simple attenuator. Looking on eBay, item 170823333195 seems to be the same as 380389276933 but the latter is obviously more expensive. Is it worth having the more expensive one? Or should I get the Smart Oxid LNB for £10 instead? Any ideas on the performance on these?

The conversion gain of the LNB that I suggested earlier (Smart Oxid) is not similar with the gain of Black Ultra (that's why it solved my overloading problem). It has a nominal minimum conversion gain of 50dB, whereas the Ultra has a nominal min. conversion gain of 60dB.

_http://www.inverto.tv/products/product.php?id=57

 

[wod]

My F15 was the decoder that had the most problems with the Black Ultra at 19.2E here (I believe most of those problems stem from the quite strong analogue transponders, which in a few days will cease to exist). So I guess it is more a case by case situation. I recently bought a Vu+ Uno, but didn't test it with the Black Ultra (F15 and the TBS6925 is indeed more sensitive than the Uno).

This is a shame as I was looking forward to getting an f15 receiver but will avoid if there are issues with it and black ultra lnbs.

I was also looking at the UNO as well but I guess not with what CJ has experienced.

 

[Captain Jack]

@ Wod, unless your cable run is less than 4 metres, you won't have any issues. It was fine with a longer run.

@ Pete, I was thinking of that and it does work but kind of sucks having a "misaligned" dish! I would like everything tidy...!

@ All, I've ordered that Spaun variable attenuator and see what good it does...

 

[wod]

@ Wod, unless your cable run is less than 4 metres, you won't have any issues. It was fine with a longer run.

@ All, I've ordered that Spaun variable attenuator and see what good it does...

Ok, my cable run is about 14metres so I should be fine.

Have you not thought of adding a few metres of cable into the situation and see if you have the problem still n see what the signal strength is like ?

Can always hide the extra bit of cable away.

 

[sonnetpete]

With all these "add cable" and "use an attenuator" solutions, they overlook the fact that CJ is having a problem that other VU+ owners don't. Which firmly puts it back on the VU+ having a tuner problem. If it's under guarantee I can't see why VU+ shouldn't replace the box without any additional cost to CJ.

@ Wod : I'm using a Black Ultra with my F15 and haven't experienced any issues with it affecting the receiver.

 

[Lazarus]

Agreed.

Sounds like an AGC fault with the individual box.

 

[Captain Jack]

Pete, probably because their cable run is longer than 4m and they are not using a Black Ultra It seems like you need the right set of conditions. I did hear that some LNBs simply don't "get on" with certain receivers. But, yes, it shouldn't really be doing it.

 

[wod]

Well it does sound like a faulty receiver which you are entitled to a replacement under the warranty.