Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




183 posts

Master Geek


# 18233 3-Jan-2008 08:42
Send private message

I've got a Zinwell "Freeview certified" decoder. From time to time the image will freeze for a second.
I've got the latest firmware that's available downloaded from the satellite.
I believe the Zinwell can overload easily.

I'm told that the easy fix is to put any size splitter between the end of the cable from the dish and the set top box.
I did that & it worked.
With & without splitter: signal quality shows as 100%.

Without splitter: signal strength shows as 84%.
With splitter: signal strength shows as 80%.

The splitter I used is one for the VHF/UHF frequency's, goes up to 900MHz (one I borrowed)
I believe I ought to use the correct type of splitter.

Four questions:
1. What are the reasons, if any, for not using the VHF/UHF splitter?
2. What is the correct frequency range of splitter, that I should get?
3. Should I go for an in-line attenuator, rather than a splitter, if so, what Db?
4. What is the optimum range for the signal strength, of this Zinwell box?

Happy New Year.

Trevor


Create new topic
6978 posts

Uber Geek

Trusted
Subscriber

  # 102639 3-Jan-2008 09:01
Send private message

Hi, and welcome to GZ. To answer your questions

Using the VHF/UHF splitter that is not rated beyond 900MHz means you have no idea what it does in the satellite L-band (950-2050MHz) so you place a whole lot of unknowns into an already unkown problem.

The Satellite LBand IF is 950-2050MHz.

A LBand rated 2way splitter will offer rougly 5.5dB loss at around 1750MHz, so yes a DC pass attenuator of 5 or 10dB would be better but are hard to find, and there is nothing really wrong with using a splitter as an attenuator.

The Zinwell box does not have a good reputation, it suffers from over sensitivity, and dodgy firmware and appears to put out lots of spectral rubbish on the RF antenna port, personally I would never buy one there are plenty of non certfied boxs from the likes of Strong and Topfield that are superiour in every way and cost less to boot.

I understand that the Zinwells are about 5-10dB over sensistive based on tests done by others using calibrated signals to assess performance. Obviously each unit will be slightly different. The quality is unlikely to change as once a reasonable C/N is achieved the decoder is fully satisfied, however the signal level could be dropped significantly and the quality never budge. Obviously if you overload the tuner intermod will work against you also as you have found.

I would get yourself a proper rated 2way splitter, they are only $12-15 at DSE, just make sure you connect the STB via the DC pass port. A normal STB is designed to have a signal acceptance range of around 40-85dBuV so quite a range(40-50dB), so you could try a 4way splitter (11dB loss) and pull the signal further into the safe zone without compromising operation.

Cyril



183 posts

Master Geek


  # 102648 3-Jan-2008 09:37
Send private message

Thank you Cyril, for such an informative reply.

I belatedly realise that I should not have bought the Zinwell.
I knew nothing about satellite gear when I did & after reading various forums, I would have bought differently.
Alas, I'm stuck with it & can only try to get the best from it.
With people such as yourself, willing to freely advise, we, with limited or no knowledge of satellite technology, can hope to steer clear of 'dodgy' stuff in the future.

Trevor


 
 
 
 




183 posts

Master Geek


  # 103515 8-Jan-2008 09:49
Send private message

I contacted the shop I bought it from & informed them of the problems I was experiencing.
They contacted Next & was informed to swap it with one from a new batch that is available.
I rang Next & asked if the replacement unit addresses the freezing & was told yes!

I installed the replacement & can report that there is no more freezing.

The signal strength now shows as 79% (no splitter used) (was 84% on old unit)
The signal quality shows 100% (after allowing for unit warm-up)
Before the unit warmed up, the signal quality would fluctuate on a few channels, between 97-99%.
I don't know if the fact that it is a completely overcast day, with some rain, could be partly responsible but after 1/2 hour, all channels were at 100% quality.

The old unit used H/W v1.0
S/W v6.0
August 20th, 2007
There was no update available from the satellite. 

New unit has same H/W version.
S/W v6.5
November 30th, 2007

6978 posts

Uber Geek

Trusted
Subscriber

  # 103520 8-Jan-2008 09:59
Send private message

Good to see you got it all sorted.

Cyril

22533 posts

Uber Geek

Trusted
Subscriber

  # 103713 8-Jan-2008 23:26
Send private message

You wont get a great deal of attenuation from a splitter if the other ports are not terminated, quite important on satillite since the modulation isnt designed to handle reflections like dvb-t is, and the signal will reflect from the unused ports mismatch. Not usually a problem unless there are a few 10s of meters of cable hanging off it however.  




Richard rich.ms

6978 posts

Uber Geek

Trusted
Subscriber

  # 103730 9-Jan-2008 08:00
Send private message

A Hills brand splitter as measured with my LBand test meter at 1156MHz (ie 12456MHz Mux) shows that terminating and not terminating one port makes around 0.5dB difference in level, ie around 4.5dB with no other port terminated 5.0dB with it terminated. As compared to a straight F-F coupler.

Ideally adding a potential reflection source is not good, however I have never noted any change in the BER with no line length attached, start adding more than 3-4meters of unterminated cable and things start to change.

Cyril

22533 posts

Uber Geek

Trusted
Subscriber

  # 103817 9-Jan-2008 15:02
Send private message

Thats interesting, in previous testing at a former employer we saw a small dip on the spectrum with connecting a splitter inline (1-1.5), and then when a load was connected to the other port, thats when it dropped down by about 5dB's   




Richard rich.ms

 
 
 
 


6978 posts

Uber Geek

Trusted
Subscriber

  # 103854 9-Jan-2008 17:46
Send private message

Will redo the test when I get a chance.

Cyril

Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

OPPO Reno2 Series lands, alongside hybrid noise-cancelling Wireless Headphones
Posted 24-Oct-2019 15:32


Waikato Data Scientists awarded $13 million from the Government
Posted 24-Oct-2019 15:27


D-Link launches Wave 2 Unified Access Points
Posted 24-Oct-2019 15:07


LG Electronics begins distributing the G8X THINQ
Posted 24-Oct-2019 10:58


Arlo unveils its first video doorbell
Posted 21-Oct-2019 08:27


New Zealand students shortlisted for James Dyson Award
Posted 21-Oct-2019 08:18


Norton LifeLock Launches Norton 360
Posted 21-Oct-2019 08:11


Microsoft New Zealand Partner Awards results
Posted 18-Oct-2019 10:18


Logitech introduces new Made for Google keyboard and mouse devices
Posted 16-Oct-2019 13:36


MATTR launches to accelerate decentralised identity
Posted 16-Oct-2019 10:28


Vodafone X-Squad powers up for customers
Posted 16-Oct-2019 08:15


D Link ANZ launches EXO Smart Mesh Wi Fi Routers with McAfee protection
Posted 15-Oct-2019 11:31


Major Japanese retailer partners with smart New Zealand technology IMAGR
Posted 14-Oct-2019 10:29


Ola pioneers one-time passcode feature to fight rideshare fraud
Posted 14-Oct-2019 10:24


Spark Sport new home of NZC matches from 2020
Posted 10-Oct-2019 09:59



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.