Looking for a 4X1 powered switch or buffer amp.

[transco]

I am looking for a powered 4X1 (4 LNBF's to 1 receiver), or an powered inline buffer amp. There are a lot of relatively cheap powered switches, but they are designed for DBS (DirectTV, etc) and select inputs based on polarity (i.e. voltage). The usual 4X1 FTA switches are powered by the feed line. I need one that has its own power supply. The other option would be a self-powered buffer amp (line driver). Suggestions?

 

[primestar31]

Why do you feel that you need a powered 4x1 diseqc switch? I've never heard of one. 4 input switches normally are only for two dual-output lnb's H and V. What are you trying to accomplish? Is this a new setup, or something that did work, but no longer does?

 

[transco]

I noticed that I was randomly 'loosing' horizontally polarized transponders. I measured the DC voltage coming out of the receiver and found it was around 17V (H) and 12V (V), dropping even lower on occasion. My guess was the LNBF was switching from (H) to (V) during some of these voltage drops. To check this, I hooked a choke isolated, variable DC power supply to the power passing side of a 2X1 coupler and the receiver to the DC isolated side. I found that (H) polarized transponders were dropping at a supply voltage of around 16.5VDC. I also tried another FTA receiver that had higher and more stable voltages going to the LNBF. It didn't 'loose' (H) polarized transponders like the first receiver. The switch, LNBF and inline 20dB amp I'm using are pulling close to 450ma and the receiver is spec'd at 500ma max load. The receiver's LNBF supply voltage is also poorly regulated and drops considerably as the load is increased.

 

[Magic Static]

That's a lot of draw for a common setup. I would try and analyze that a little more a find out what each piece is drawing for power. The use of an inline amp suggests you have a very long coax run. Can you upgrade the long run of coax to RG11 and get rid of the amp? I run power hungry PLLs and push out over one amp thru a DTV powered 4x8 multi-switch. Using voltage switched polarity control makes it difficult to use an inline power inserter.

 

[Anole]

- what receiver (there might be a fix for it)
- what kind of cable? One piece?
- how long a run?
- what LNBF?
.
Have you tried operating without your amplifier? What were the results?

 

[transco]

The heavy current draw was due to the C/Ku band LNBF I was using. I swapped that out and the current draw dropped in half. I seem to still have a problem. Here is what I'm doing... From the receiver I go into a 4x1 DiSEqC 1.0 switch. One port of the switch goes to a 1M dish with a Stab DiSEqC 1.2 H to H rotor (actually 140 degree rotation) and Ku band LNBF (there is also a CP LNBF, but I'll keep things simple here). The rotor uses 'USALS' positioning. Another port of the switch goes to a DiSEqC 1.2 G-Box which powers the jack on a 3M dish and a C/Ku band LNBF with an internal 22kHz band switch). I discovered today that the 4X1 switch keeps switching ports rather than staying on the one I specify in the setup. It would appear you can't mix DiSEqC 1.0 and DiSEqC 1.2 hardware. The DiSeqC 1.2 commands to the motors seems to be causing the DiSEqC 1.0 to switch as well. I've always used this configuration for my FTA receivers. Why this is a problem all of a sudden is beyond me. I tried 5 different 4X1 switches and all behaved the same. To verify this was what was happening, I set the switch to an unused port (with a 75 ohm terminator on all unused ports). A few seconds later, the receiver was getting a signal from the switch. It didn't matter which port I put the signal on, eventually it would appear on all unused ports. If it was leakage or crosstalk in the switch I would expect it to be constant, rather than coming and going at regular intervals. I guess this thing to do now is see if I can find a suitable DiSEqC 1.2 switch.