dual c dual ku ortho feedhorn revisited (1 Viewer)

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truckracer

SatelliteGuys Pro
Sep 17, 2004
4,338
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Charleston wv
I know last year we had a significant amount of posts regarding dual c dual ku feedhorns. As some of you know i am running one on my 10' dish.

very happy and very high performance unit. I even have cheap lnb's and it still amazes me.

I am using two zinnwell 3x4 (vertical / horizontal / terrestrial antenna) input with 4 receiver outputs. One switch is on the C band lnbs and the other is on the ku with two coaxes leading back to the house into my dsr-905 and out to a diseqc switch feeding my pansat 9200.

I had some corrosion problems with connectors outside on the multiswitches so in messing around diagnosing my signal issues I used a barrell connector to eliminate a switch. My signal went up about 15% (quality).

couldn't believe those switches were killing the signal that much.

THese are passive non powered switches so maybe its the volt drop from the pin diodes in the switch feeding the lnbs

I thought about those power inserters from sadoun. the switchable ones that can feed 17/18 out to both ports if the switch is selected to do so.

I wonder if that will further increase insertion loss or will it help since my vertical lnb is getting 13 volts (or less maybe). I have never measured the vertical volts with the lnb connected under load. the power has to leave the pansat through a diseqc switch down 150' rg6, into the zinnwell switch and then to the lnbs.
I would imagine the volts are dropping quite a bit.

has anyone used the power inserters in this situation? or a similar setup?
 
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pendragon

SatelliteGuys Pro
Oct 13, 2008
1,100
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There's a good chance the real problem is the passive switches. I've seen SQ drops like this before. My recommendation would be to use a single powered switch instead. You can find them for next to nothing and you will have to run an extra coax for power, but it will be much easier than trying the power inserter route.
 

ACRadio

SatelliteGuys Pro
Apr 25, 2006
794
0
Near Asheville NC
....but it will still only send 13 volts to the vertical LNB's. The KU LNB's usually don't mind as much as the C band LNB's. I've seen Q's drop 6 to 8 points when sending 13 volts to the C LNB's and I have had LNB's that wouldn't work at all with vertical voltage. I use Spaun SMS 5802's with the dual power inserters and the Q increased only 1 point when running the signal straight to the receiver.
 

pendragon

SatelliteGuys Pro
Oct 13, 2008
1,100
63
Yeah, I wasn't paying attention to the ortho feed LNBs. Those normally should get 18V each, at least. The diagnostic question then becomes do you see a noticeable difference between the H & V LNBs with the switch in/out?

If you're losing measurable SQ on both polarizations with the switch inserted vs. out, the switch is a problem. If you don't want to go the powered switch route, a number of people think the Zinwell 4x4s are pretty good. However I've measured some degradation even on those. I'd still recommend powered switches.

If you're losing SQ only on the vertical LNBs, then a power inserter or a modified powered switch is in order. Power inserters can be implemented using off-the-shelf parts, but they are often higher in overall cost and require more cabling. The WNC SWA-48 (4x8) switches are very inexpensive and easy to open/mod:

http://www.satelliteguys.us/fta-shack/174802-naughty-mods-ii-4x8-switch-all-18v-outputs.html

Someone else did a mod on a powered 3x4:

http://www.satelliteguys.us/c-band-...-modify-powered-3x4-multi-switch-show-me.html
 

pendragon

SatelliteGuys Pro
Oct 13, 2008
1,100
63
where do i getthe switch.

I bought over a dozen on eBay for an average, shipped price below $10. Anole also found them on Amazon. Make sure you look for both the SWA-48 and its apparent replacement, the MS4x8WB-WNC. Just make sure it's the same unit as pictured in my thread. There are a fair number of mislabeled ads.
 
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