v8 golden signal with and without DiSEqC switch

[kolithawick]

I got V8 golden about two weeks ago. it is connected to two dishes through DiSEqC switch (Ku and C) working ok.
yesterday i remove DiSEqC switch and connected directly to C dish.
in C band also only few TPs ok. others no signal.
DiSEqC connected again all C band TPs ok.
Why this happened? problem in V8 tuner. pls help me.

[sickboy]

What kind/type of Diseqc switch ? Did you change the settings to match the fact you removed the switch from the chain ?

This is not a problem with the tuner, explain more about your setup.

[kolithawick]

it is 4 port DiSEqC 1.0 switch.
To check this I did this.
connected dish directly to v8 and do a blind scan. again connected through switch and do a blind scan.
I can receive more TPs when switch is connected. It looks like switch is acting as a signal booster or receiver has some problem.

[Feralkiwi]

I have had these kind of problems with DiSEqC switching on Freesat units for over a year.
The issue I have found is that the units over current protection for the LNB is tripping in.
My set up has cascade switching. That is a 8 port DiSEqC 1.1 switch and then many DiSEqC 1.0 switches after that.
The current surge when the 8 port 1.1 switch powers on the second switch and the LNB is more than the unit can take.

I fixed this by adding a signal splitter at the STB which limits the current surge.

Some LNB's like "One Cable Solution" LNB's use around 200mA.

Your problem maybe that when the V8 Golden is using Horizontal polarity ("H" 18Volt) the current draw is too high.
Are the TP's that are not working all "H"?

When the DiSEqC switch is in circuit there is added impedance that helps limit the current surge.

I have a new Freesat unit here that will not power just a One Cable Solution LNB.

Owen

[kolithawick]

Thank you very much for your valued explanation. But it looks like the problem is different. it effects the Vertical tps and Ku band also.
(earlier I did't notice this because of Ku bands strong signals.)
see attached screen shots. First one with switch and second one without switch.
open cct voltage out from v8 is
V=14.2v and H=19.7v

Photo0260.jpg (54.65 KiB) Viewed 10849 times

Photo0254.jpg (55.44 KiB) Viewed 10849 times

[sickboy]

How are you connecting directly to lnb ? Are you connecting the two lengths of existing coax with an in-line coupler or a separate length of cable ?

[Feralkiwi]

I agree with sickboy.
Check what you are using in place of the 4 port switch.
You may have a high loss cable or connector.

Owen

[cpr43]

Diseqc is decreasing the power to the LNB.

[kolithawick]

My switch is inside home and cable is long enough to connect directly to receiver so nothing is in between.
I also agree there must be loss in the switch.
Yesterday I borrowed a receiver from a friend of mine and connected to the system and problem is not there.
so this must be a problem in this particular unit of V8 golden.
Impedence mismatch and high VSWR I think.
so pls advice me what can I do to solve this?

[sickboy]

This doesn't make sense at all. Using a switch and an extra coax cable should cause a loss. I would normally say the receiver is not really seeing a change (but for some other reason is reporting one) but you have measurable loss if you are dropping transponders. Very odd and I don't know what to make of it.

[Feralkiwi]

Hi

A few more questions.

When you connect to the C band dish directly is there anything else connected?
The same question for the Ku band?
STB to cable to LNB only?

Is there any TP's lost if you connect the STB to cable to DiSEqC switch to cable to C Band LNB?
That is with the Ku dish cable disconnected from the switch.

Same thing for the Ku connected through the switch with out the C Band dish.

If there are no TP's lost with the switch connected then it is the switch that is improving The signal.
The question is then why. Maybe the switch is reducing the voltage level for your type of LNB.

If not then the signal is improved by having both cables connected, ku and C band.
This could be due to earth loop currents being removed by having both dishes connected.

Just one more thing. If you have connected both the Ku and C together through a splitter instead of the switch you will loose frequencies that are common to both. I doubt you have done this.

Are your Ku and C dishes separate dishes or are they a combo ku/c lnb like this one?

What type of LNB's do you have?

Owen

[kolithawick]

Here is the answers for your questions.

When you connect to the C band dish directly is there anything else connected? No nothing
The same question for the Ku band? No nothing
STB to cable to LNB only? Yes it is correct

Is there any TP's lost if you connect the STB to cable to DiSEqC switch to cable to C Band LNB?
That is with the Ku dish cable disconnected from the switch. No there is no difference with or without Ku cable

Same thing for the Ku connected through the switch with out the C Band dish. No there is no difference with or without C cable


If there are no TP's lost with the switch connected then it is the switch that is improving The signal.
The question is then why. Maybe the switch is reducing the voltage level for your type of LNB.
What I feel is there is a problem in input impedence of receiver and swich is acting as a impedance matcher.
(something wrong in front end of tuner)

If not then the signal is improved by having both cables connected, ku and C band.
This could be due to earth loop currents being removed by having both dishes connected.does not apply

Just one more thing. If you have connected both the Ku and C together through a splitter instead of the switch you will loose frequencies that are common to both. I doubt you have done this.No sir I can identify splitter and switch very well.
if that is so we must loose signal here it is a gain.

Are your Ku and C dishes separate dishes or are they a combo ku/c lnb like this one?
No it is two seperate lnbs in two seperate dishes.
C band lnb Eurostar ESCD-600 Gold and Ku band lnb Sharp BS1K1EL182A

When I connected another V8 golden borrowed from a friend of mine problem is not there so it must be a problem of this unit.
pls advice me how to solve this poblem.

[Xsat]

I experienced a similar situation with Freesat V7.
Freesat's model is very sensitive to antenna short circuit protection.
The other company is 500 mA, but Freesat is 400 mA.
Symptoms are remarkable especially when using DiSEqC switch.
Therefore, loss of signal occurs especially with horizontally polarized wave and it can not be received.

Does your problem occur when you receive horizontal polarization?

[Feralkiwi]

Thanks for the answers.

I am interested as I have had many problems with power etc on the Freesat units LNB circuit.

My first V7HD ( the first one sold by Freesat through their Winsat Tech aliexpress store) worked all my switch network.
The next one I got showed a few problems with some dishes / LNB's.
The next ten I brought would not work at all unless I added the Signal splitter at the STB to limit the current surge.

The LNB input modules that Freesat are using now are not as good as that first V7HD.

As I said before the latest Freesat unit I have will power very little.

It is my guise that the other V8 Golden that does work on your dishes is an older unit.

As for a fix. If you brought it localy you could take it back.
If you brought is via aliexpress or the like overseas then the cost of returning it will stop you from returning, as I have had with other brand units.

I live with the fact that I need a splitter at the STB to make all my newer freesat units work on my switch network.
These include the full range of V8 and V7's, they all need this splitter.

If, as I suspect, Freesat has changed the RF / LNB input unit to one that causes even more problems, then getting a new unit will likely give the same result.

For the cost of these freesat units you do get most things to work. Adding the cost of a DiSEqC switch to keep that working is the best answer.
I have brought a $300NZ USA made unit that the Freesat units out perform. That unit gathers dust on the shelf.

Thanks again for answering my questions.
Sorry there is no solution.

Owen

[Feralkiwi]

I experienced a similar situation with Freesat V7.
Freesat's model is very sensitive to antenna short circuit protection.
The other company is 500 mA, but Freesat is 400 mA.
Symptoms are remarkable especially when using DiSEqC switch.
Therefore, loss of signal occurs especially with horizontally polarized wave and it can not be received.

Does your problem occur when you receive horizontal polarization?

Please have a look at my post here re the V8 Finder.

Owen

[kolithawick]

Thank you very much for taking so much time for helping me.
It is great pleasure to discuss with people like you who can understand technical matters very well.

I brought this from a seller in ebay. I will email him with reference to this and see what he can do to solve this.

thank you very much again
Kolitha.

[sickboy]

If you don't mind me asking why is it important for this to work without the switch when you're setup (c + ku) requires one ?

[kolithawick]

You are welcome sir
As technical people we always like to know why and how for all abnormal things when it happened.
further to that I feel that I will be able to receive more weaker TPs than now if receiver does not have this problem.

[sickboy]

Not sure if you've stated or not but I would do a factory reset and reload/upgrade the firmware in case there is a software bug causing this anomoly.

[kolithawick]

It is already updated to V538 of 24-3-2017.
this can't be a software problem it is hardware.

[vivian]

I got V8 golden about two weeks ago. it is connected to two dishes through DiSEqC switch (Ku and C) working ok.
yesterday i remove DiSEqC switch and connected directly to C dish.
in C band also only few TPs ok. others no signal.
DiSEqC connected again all C band TPs ok.
Why this happened? problem in V8 tuner. pls help me.

Could you show me your DiSEqC switch picture?Thanks!

[kolithawick]

this is the switch.

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[kolithawick]

Dear Feralkivi,
I have found the problem in my V8 golden receiver and found a solution also.
For the benefit of other members and, if the problem is in other units also hardware engineers to look into this, I thought to post it in the forum.
The problem is in LNB power from the receiver. It has more than 6v ripple in power line. When switch is connected electronics in switch acts as
ripple filter.
I designed a simple ripple filter. As I didn't want to oped the box and modify it I thought to fix the filter to the LNB cable.
to avoid half and quarter wave length resonance I cut the cable about 1.5 meters away from the receiver and fixed the filter shown in the photo.
The results were excellent, the TPs I received with 80% signal strength earlier now 95%.
and got dozens of TPs with about 75% signal strength which I could't receive earlier.
I receiver is working fine now.

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Photo0266.jpg (30.07 KiB) Viewed 10159 times

[Feralkiwi]

Thanks for that.

Yes I too have thought that the power supply for the LNB is not good.

The latest Freesat V8 Finder is not good.
The 18 volts for the LNB needs to be made from the 7.2 volt battery instead of from the 12 volt main power supply.
This too would make more "ripple" in the lnb supply and if the frequency is close to 22kHz, the DiSEqC switching will not work.

I brought parts today to test the V8 Finder.

Results soon.

I will also look again at the other units, the V8 and V7.
What frequency did you find the ripple was?

Your unit may not have all its components. The 18v LNB supply electrolytic cap in particular.
I brought another band unit a year or more ago and the large capacitors were not hand fitted and the 18v circuit did not work.
Also if the 18v LNB supply cap is electrolytic, as I have seen it is, and if it is a 25 v cap as I have seen, then a 6v ripple will push it close to it's 25v, 18 + 3=21 volts.
The cap will puncture and not work as well.

Again thanks for your reply. I too hope the engineers take note.

Out with the oscilloscope etc tomorrow.

Edited Friday 21 added results link.
My results are posted on this forum.

Owen

[kolithawick]

sorry Feralkivi, I am using a home made oscilloscope made from a tv CRT so time scale is not accurate.
so I can not get a correct idea about frequency.