General Forum

Re: Link tv picture quality

Beobuddy — Tue, 07 Apr 2009 15:14:43 GMT

Should have read the link Keith supplied.

I did hear something about this, but never looked any further for info.

It could simplify the excisting situation. Less could be more in this case.

Re: Link tv picture quality

DoubleU — Tue, 07 Apr 2009 13:24:12 GMT

Beobuddy:

Wouldn't that be behind the BV5?

Otherwise you don't have the superposponed (sorry, don't know correct english term) signal from any source attached to the BV5.

Not with the link amplifier, Keith described.

Re: Link tv picture quality

Beobuddy — Tue, 07 Apr 2009 12:43:28 GMT

Keith Saunders:

The link amplifier would normally be placed somewhere between the incoming analogue TV aerial and the Beovision 5.

Wouldn't that be behind the BV5?

Otherwise you don't have the superposponed (sorry, don't know correct english term) signal from any source attached to the BV5.

In my system I start with a special divider/seperator between the outside cable network and the inside network. From the divider it goes to the BV5, then from the BV5 RF output to an amplifier which boosts the signal several dB's.

After the amplifier I have multitap to which every linkroom has its own connection.

Just the way I did it.

Re: Link tv picture quality

Keith Saunders — Tue, 07 Apr 2009 03:47:59 GMT

Emil,

The core reason for a good picture with DVD and poor with the analogue signal relates to the fact that the RF signal from the Beovision 5 uses the "link" frequency which has a default frequency of 591 Mhz whereas the analogue channel you are watching can be between Channel 21 (474 Mhz) and channel 68 (850 Mhz). Your RF link cable network and termination are designed to be 75 ohms inpedance which is effected by frequency and even the very best installation is a compromise when directly connected to more than two point (two link TV's for example)

The solution is to not connect directly link TV's RF cables, but use an RF amplfier which also takes in the analogue signal from the aerial seperate to the Beovision 5.

You will need only one amplifier for use with one master TV and up to 3 link TV's

The link amplifier would normally be placed somewhere between the incoming analogue TV aerial and the Beovision 5.

There would be seperate coax cables run from each link TV back to the amplifier. The key point being that each TV aerial input is connected to the RF amplifer.

If, due to problems with changing the link wiring (perhaps because it is already in the wall) then a second amplfier can be connected to the first, but try and avoid this solution.

Re: Link tv picture quality

Emil — Tue, 07 Apr 2009 02:18:03 GMT

Hi all,

Many thanks for your swift replies. What really confused me is that I got a decent picture when watching dvd:s on the link room tv:s but not when watching an ordinary analogue broadcasting. I am not an technician but given Keith's answer there seems to be a probable answer to that issue at least.

Keith, as regards your proposed solution with the RF link amplifier should I use one or two amplifiers? The both link tv:s are quite close to each other so I would like to avoid having two RF cables from the amplifer to each of the tv:s. As things are now I have one cable from the master tv to the first link tv (BV7) and then from the first link tv to the second link tv (BV6). Would one amplifier do the job or should I connect another one between the BV7 and the BV6?

Regards,

Emil

Re: Link tv picture quality

Keith Saunders — Tue, 07 Apr 2009 01:50:57 GMT

Emil,

If I have correctly understood your problem, then I would say you have a problem with impedance mis-matching of your RF link from your Beovision 5. This in my experience is one of the most common issues found with link system particularly when you are using several link TV's.

Whilst using a good quality cable is important, its in its termination where most problems start and also if any one TV connected to the RF signal has a slight mismatch, it will effect them all. Also, because frequency and impedance are directly linked , using a link TV to watch an analogue signal may give poor results, yet watching a DVD appears fine.

The best solution and one which B&O recommends is the use of a balanced termination amplfier. This means that each link TV is connected using "F" connectors to its own impedance balanced output, so any in-balance on one link TV will not affect the others and the standard analogue frequencies are multiplexed via their own input.

Have a look HERE for further information which should answer most of your questions, but if not then come back to us.

Re: Link tv picture quality

moxxey — Mon, 06 Apr 2009 17:11:05 GMT

I'm sure this is of no help, but you want to compare the PQ from a HD-sourced BV7-40 compared to a link room BV8. Mt BV7-40 is connected to a Sky HD box and I'm used to watching a lot of TV in HD.

However, as the link room system is based on an analogue RF signal, the link room TV PQ is awful, in comparison! Now, I probably wouldn't have noticed if I'd never used or have seen a HD picture on my BV7-40, but that's not the point.

B&O really need a digital modern link room system, and ASAP.

Re: Link tv picture quality

Nickyg63 — Mon, 06 Apr 2009 15:49:40 GMT

If you have more than one link tv it is advisable to have a signal booster, hope that helps

Cheers Nick

Link tv picture quality

Emil — Mon, 06 Apr 2009 15:40:54 GMT

Hi all,

I some problems with the picture quality on my two linked Beovisions. When looking on a dvd or v-mem recording sent from the master tv (BV5) to any of the link tv:s (BV7 Mk1 as first link tv and BV6 mk 1 as second link tv) the pq is quite ok. Not excellent but ok. However, when watching an ordinary tv programme on any of the link tv:s the pq is really bad. Even worse if both tv:s should be on at the same time.

I've done some searching on the forum and come to understand the importance of high quality RF cable etc. but what beats me is why the dvd and v-mem signals from the master tv gives an ok pq while the same cannot be said about the ordinary tv channels? Picture is fine on the master tv so it can't be the analogue tv-signal itself.

I have tried to change the link tv frequency of the master tv without any visible improvement on the link tv:s. I did however notice that when I tried to change the link tv frequency of the link tv:s in accordance with the user guides of the BV 6 & 7 (never really able to though since I came direct to the fine tune menu. It seems as the tv:s autodetect the new frequency) it seemed as if I could make use of the analogue receiver of the master tv and have the picture sent to the link tv:s with better result. Problem with this solution is that

1. I can only watch the same programme at the same time on the tv:s, thereby excluding the rest of the family who does not always have the same preferences as me,

2. Stored memory pages on text tv are no longer available on the link tv:s, and

3. I have to do the same operation again if the tv is shut off. The link tv:s doesn't store anything.

Any input on what I am doing wrong would be highly appreciated. I have no RF amplifier installed but since the pq is ok when sending dvd and v-mem signals as well as when I'm trying to adjust the frequency of the link tv:s I am not really sure that it is the strength of the signal sent from the master tv (or from the BV7 to the BV6) that should be blaimed.

Regards,

Emil