Ku system bench test

[AllWxFlyer]

Hi All,

I've been trying to install a Ku band system (off and on) for the past
3 weeks and have had zero success. I'm running a Merc II rcvr,
QPH031 LNB and Fortec 90cm dish, S-SM21H switch. Location is 42.40N/71.22W, in
NE Mass. As far as the system is concerned, there isn't a bird in the
sky.

I have the LNB/RCVR/switch setup on the bench at work (I work as
a tech in the TV bcst industry). Not being familiar with the switches,
it does switch 14/18 vdc, and I hear alot of switching every 5 sec or
so. Ran 1-linear, 1-circ LNB output to it for testing, then took it out
of the setup.

I'm using an HP 8672A supergen at 12144mhz to a 12 gig ant for a
signal source, @ -35dBm output. The LNB is connected to the rcvr
via 3ft of RG6. I'm using the rcvr loop output to an HP8563A 26 GC
analyzer. Video out from the rcvr is to a JVC monitor.

The problem (I think) I'm having is that I'm showing a conversion
LOSS from the LNB. The signal source ant is only about 2ft from
the LNB and I have the signal peaked. The spectrum is showing
about -48dBm on the spectrum. And the sig qual and level
indications on the ant setup is staying around 2-4% each with
occasional Qual spikes to around 70%. Signal level never goes above
5%. Also, the Qual level doesn't agree with the signal peak on
the spectrum. BTW, the switch is NOT in circuit.
The Satfinder meter (in line) is very touchy also.

The config on the antenna setup screen is:
SAT AMC6 72.0W (my south sat).
LNB 10750 L.O. (using one of the linear LNB outputs0
TR 12144/V/2573
0/22khz Off
Sw None
Input None
Port (1=greyed out)

I'm about ready to get the Dish 500 LNB I have in the truck, and
throw it on the bench for comparison.

I'm a bit confused as to where the problem is, but I'm leaning
towards the LNB as being bad.
There should be a pretty big conversion gain in that thing and I'm
just not seeing it.

Am I going about this the wrong way? If so, tips, suggestions or
anything else (except a hammer) would be appreciatet.
I'm not gonna let this thing get the best of me.

TIA for the help,

John

 

[AllWxFlyer]

Additional info, all 4 outputs from the LNB are acting approx the same way.
John

 

[qwert1515]

My recommendation is to try a different frequency than TR 12144/V/2573 since it can be hard to lock sometime.

Use 12068 V 9755.

 

[Anole]

Well, following the KISS principle, I'd skip all the test equipment.
Often, that just obscures the problem.

Rule #1, LNBs are hardly ever at fault.
Is yours new?
What sort of dish do you have it on?

If I may suggest, hook a $10 signal meter between receiver and one Circular connection on the LNB.
Then, scan the sky looking for a bird. . . with that meter!
If you can't find one of those noisy satellites, you're on the wrong planet!

Once you have any DBS service located, look for a few more.
You'll find hot signals up there at 61, 77, 82, 91, 110, 119, 129, and 148.
Probably some more that I left out.
edit: If you mark the azimuth and elevation of a few of these on your pole and mount, you'll be able to use those marks later to locate linear birds.

Rule #2, if you use a hammer on something, it most likely would have worked for someone with more patience.