c-band lnb

[rdel]

I should post this in c-band but it seems everyone is in fta area.
When choosing a new c-band lnb for my chaperell, what is the better lnb, a 17 or 15 or 13 degree? Is the c-band lnb like the ku band? (lower the number the better)
thanks guys
rdel

 

[voomvoom]

Yes it's still the lower the better. But, you should also look at the +/- on the khz rating. It too is the lower the better. The best would be a +/- 5 khz and would probably cost $400+. Here are some examples of what I'm talking about:
http://www.sepatriot.com/LNB Norsat.htm
The 8215 is +/- 250 khz and the 8115 is +/- 100 khz, the price is a $25 difference, but the 8115 is the better of the two. They are both 15k lnb's. Truth is, you might not notice it, then again, maybe you would.

Al

 

[rdel]

Thanks VOOMVOOM
rdel

 

[Tron]

L.O. stability (what Al is talking about) makes a great deal of difference. I've got a .9 Norsat on my Channel Master (1 meter) that performs about the same as my .3 Invacom (on a 90 cm). The .9 Norsat has a L.O. stability of +/- 100 khz...

 

[tdti1]

The temp is not really impotant, it's the LO stability, the Norsat 8215 is good the 8115 is better.

 

[GrumpyGuy]

The importance of stability has been demonstrated to me in a big way when experimenting with SCPC audio on C-band. As the feedhorn cover moved into or out of the sun the IF of the receiver would drift, not enough to effect NTSC video, but narrow little audio carriers would go dancing across the dial of my homebrew SCPC receiver.

Gave some thought rigging an thermostatically controlled oven for the LNB to keep it at about 90 deg. or so ... like a lot of things, never go around to it.

 

[voomvoom]

L.O. stability (what Al is talking about)

Thanks Tron, when I posted above, I just couldn't get "L.O. stability" off the tip of my tonge. And yes, that's what I'm talking about.

Al

 

[rdel]

What your saying is the sun during the daytime can cause problems for my c-band lnb. Is that the reason why my channels (5 nets on g16) work great at night and lousy in the daytime? (5 ft dish with uncovered chaparral feedhorn. older model lnb)
I was thinking about changing the lnb to this one
http://cgi.ebay.com/ws/eBayISAPI.dl...20033726273&rd=1&sspagename=STRK:MEWA:IT&rd=1

but the lo stability is 1 mhz

Which of the three would you recommend? I'm only going after the nets on g16 and I don't need a c-band lnb that can pickup ku-band.
Replace the old lnb with this
http://cgi.ebay.com/ws/eBayISAPI.dl...20033726273&rd=1&sspagename=STRK:MEWA:IT&rd=1
Or get one of these to take the place of my chaparral
http://cgi.ebay.com/ws/eBayISAPI.dl...40018370441&rd=1&sspagename=STRK:MEWA:IT&rd=1

http://cgi.ebay.com/ws/eBayISAPI.dl...80007417380&rd=1&sspagename=STRK:MEWA:IT&rd=1

Thanks Guys
rdel (newby to c-band)

 

[tdti1]

With LO that high I personally would not touch any of them, like metioned above if you want good C-band lnb's go with the Norsat 8215 250 kHz or the 8115 100 khz, since you dish is so undersized the 8115 or 3220 10KHz would be the best bet, the 8115 is a DRO lnb the 3220 is a PLL.

Cal amp also has great lnb's.

You may also want to get a bigger dish.

 

[rdel]

Thanks tdti1, voomvoom, grumpyguy and tron. You gave me alot to think about.
What about the heat affecting a c-band lnb, does it really happen?
rdel

 

[tdti1]

Thanks tdti1, voomvoom, grumpyguy and tron. You gave me alot to think about.
What about the heat affecting a c-band lnb, does it really happen?
rdel

Yes and no, you will notice it on cheap lnb's like the ones you had linked, the LO of 1000khz and 1500khz will be very poor, and with the heat in the feed cover the lnb gets warm and will not lock and hold signals good, a quality lnb should not have these issues, stability of 250khz or lower is a good choice to make well worth the extra money.

 

[voomvoom]

The only time I experienced a heat problem, was with an "LNA" back in the early 80's. It was a 125 degree LNA, and if I remember right it was a Drake model, although it may have been a Chapparel. I have no idea what the L.O. stability was? That was a long time ago, and things have gotten a whole lot better since then.

Al

 

[rdel]

Thanks tdt1 and voomvoom.:
rdel