Losing TPs on C-band...

[Cham]

Been noticing some TPs seem to be intermittently disappearing from several satellites. Usually horizontal TPs but some vertical TPs as well.
I am using a C2W-PLL, Zinwell 4803, and diseqc switch to receiver. Also have an SL2PLL connected to the Zinwell switch. The Ku seems to be fine through the switches. I have three receivers connected to the zinwell via diseqc switches. All three receivers exhibit the same behavior, same TPs. Using the factory power supply for the Zinwell.

Wonder if the Zinwell is overloaded regarding current capacity running two PLL LNBFs?

I have a C2 LNBF I might try out (if it's not too windy today (+15 deg F out right now..)

 

[Titanium]

See if the voltage feeding the C-band LNBF or switch is dropping below 17Vdc for horizontal or 11Vdc for vertical transponders. If so, the switch may not be selecting the correct input or polarity.

Is the multi-switch external powered? If not, that would be my first suggestion for troubleshooting and reliable operation.

 

[Cham]

Hi Brian,
The multi-switch is powered by an external power supply (comes packaged with the switch), and has a 1 amp rating @ 24Vdc. I am guessing the two LNBFs use up about 300-350 mA, with some loss and power supply inefficiency.

Guess I will have to check two things;
1) -in-circuit voltage to the C2W-PLL from the Zinwell horizontal port (18Vdc + or - 1V)

2) -in-circuit voltage and current supplied to the Zinwell (4803) from the 24v power supply.

That means I have to go outside with some test equipment... and it just started to snow...

To digress somewhat,
I have a 16/3 (Cu) AC extension cord running out to the dishes to supply 115Vac to the switch p/s. I have been thinking of using the cord to supply the 24VDC to the switch(s) (thinking of adding another Zinwell switch) instead of high AC voltage. The extension cord is running through the conduit that connects to the house and is about 60' long. I could just splice DC connectors in place of the 115Vac receptacle and have a beefier 5A 24Vdc power supply inside the house... I am thinking 2A through 60' 16ga Cu should allow voltage to stay within 1/2 a volt?
Think I have a slide-rule calculator somewhere for cable length resistive losses but can't find it! Will look on the web I guess...

 

[Magic Static]

The switch is rated at 750ma. I overloaded one with PLL LNBs and ran it for about a year before it started having the H Ku port start dropping off. I finally had to replace it and use a different power insertion solution. But it was the heat factor that killed the switch. Pushing all that current made it run too hot. On hot days I couldn't keep it cool enough.

 

[fred555]

Been noticing some TPs seem to be intermittently disappearing from several satellites. Usually horizontal TPs but some vertical TPs as well.
I am using a C2W-PLL, Zinwell 4803, and diseqc switch to receiver. Also have an SL2PLL connected to the Zinwell switch. The Ku seems to be fine through the switches. I have three receivers connected to the zinwell via diseqc switches. All three receivers exhibit the same behavior, same TPs. Using the factory power supply for the Zinwell.

Wonder if the Zinwell is overloaded regarding current capacity running two PLL LNBFs?

I have a C2 LNBF I might try out (if it's not too windy today (+15 deg F out right now..)

Those Zinwells do get pretty hot, but after about a year I've had no issues. I have four switches now together in an enclosure in the shade. The mounting brackets for them do act as sort of a heat sink however. But still they are enclosed with no airflow.

I run four separate factory 1 amp power supplies in an enclosure plugged directly into an outdoor outlet. I use coax from the power supplies to the switches about 25 feet in length. I also have some runs from the multiswich to LNBFs that are as long as 75 feet. I have a mix of PLLs on my #1 and #3 switch. My #1 switch has the exact combo as you. My #3 is running 3 LNB(f)s, albeit 2 are single output.

The only problem Ive had so far is my 125W LNBF on my 6 footer went bad and put a Corortor II on it for Ku.

If those voltages are squirrelly do you have a spare 4803?
How long is the run from the 4803 to the C2W-PLL?



I purposely did not put two C2W-PLLs on the same switch:

#4 for is waiting for a bigger dish for 30W.

 

[Cham]

Tnx Fred!
Ok.
17.8Vdc from the H output (to LNBF), and open circuit is 18.4Vdc. This is checked at the switch, not at the LNBF, maybe 12 ft cable between LNBF and switch.
Add another 1/2V voltage drop from 12' cable to LNBF and we are very close to the voltage cutoff for H polarity.
Power supply is at 23.8Vdc loaded, 24.5V open circuit.

Also checked the mains voltage and we are down to 102Vac where the extension cord is plugged into the house. Other side of the circuit is only 100Vac, with 203Vac across both sides. Someone must be using a lot of power on our distribution line. It was quite cold last couple of days with lows below 0F... and I remember the UPSs making funny noises once in a while the last couple of days.

I have two spare 4803s, but I am going to switch out the C-band LNBF just to see what that does over the next day or two.

 

[fred555]

Also checked the mains voltage and we are down to 102Vac where the extension cord is plugged into the house. Other side of the circuit is only 100Vac, with 203Vac across both sides. Someone must be using a lot of power on our distribution line. It was quite cold last couple of days with lows below 0F... and I remember the UPSs making funny noises once in a while the last couple of days.

Yikes, 100 Volts. About 15 volts less then mine.

 

[fred555]

Tnx Fred!
Ok.
17.8Vdc from the H output (to LNBF), and open circuit is 18.4Vdc. This is checked at the switch, not at the LNBF, maybe 12 ft cable between LNBF and switch.
Add another 1/2V voltage drop from 12' cable to LNBF and we are very close to the voltage cutoff for H polarity.
Power supply is at 23.8Vdc loaded, 24.5V open circuit.

Also checked the mains voltage and we are down to 102Vac where the extension cord is plugged into the house. Other side of the circuit is only 100Vac, with 203Vac across both sides. Someone must be using a lot of power on our distribution line. It was quite cold last couple of days with lows below 0F... and I remember the UPSs making funny noises once in a while the last couple of days.

I have two spare 4803s, but I am going to switch out the C-band LNBF just to see what that does over the next day or two.

I respect a man that has spares.

 

[Cham]

Process of elimination... simplest way to diagnose a problem without fancy test equipment...

The RG6 leads between the C2WPLL and the Zinwell switch are brand new quad shielded, solid Cu center conductor cables swept to 3GHz (until I put the connectors on that is).

I should also mention the setup is working perfectly today. Good signals at all the usual places. I am thinking the Zinwell power supply regulation is linked to the input voltage instead of the output, and as the input drops the output drops as well. Might fire up the standby generator and check this theory!

 

[Titanium]

The horizontal polarity switch point minimum voltage should be approximately 16Vdc. Anything less than that is hit and miss.

 

[Cham]

Just checked line voltage again and we are back up to 120Vac (called the power company). Checked the Zinwell supply and I get 30.2Vdc / 25.1Vdc open/closed, and 18.2 on the 18v port to the LNBF. Me thinks all my troubles are with the power company!
Will keep an eye on the line voltage...
I don't like that high open circuit voltage on the Zinwell power supply but I suppose it requires a load to ballast the regulator circuit. I should look through my junQue boxes for items that could be assembled into a better regulated supply...
Didn't switch out the LNBF yet.

 

[fred555]

Let us know if your still losing tps. It may be possible judging by the beeping ups you could have gone even below 100 volts at times. I will cross my fingers.

 

[Cham]

Power has been stable since I called and complained. Likely had something set up wrong in the local sub-station causing the line voltage to drop below specs.

Still losing some TPs occasionally (not as bad though), usually in the morning or evening. Really strange... re-aiming the dish didn't help.

Just for fun I replaced the C2W-PLL with a C2 I had kicking around and that seems to fix the problem. Can even scan in that 16PSK TP on G19 (not a hint of it before changing out the LNBF). Been working for several days now and no signal drop-outs.

Weather turned really cold, setup is still working fine at -25C.