lnb mods

[ob111]

hey all
I was just wondering if there were any lnb mods to maybe get a stronger signal
I found a standard B3V dish with lnb in a scrap metal bin so I grabbed the lnb
and took it home and dissected it
very interesting inside these I was looking at the glass in the stem and wondered what if it was side ways then I popped of the back cover and noticed the two trimming pots probably hor./vert. but not sure and curious.
any electronics experts ever played in these things?

[homer_™]

Here's a link that contains some good info on LNBs


http://www.satcure.co.uk/tech/lnb.htm

[Bowhunters]

Excellent site

[Terryl]

If you don’t have a dual channel spectrum analyzer a frequency counter and a couple of RF generators that can go to 20 GHz there is not much you can do to increase the gain on the LNB, (they are pretty well maxed out as is) the adjustments are for the combiner and isolator, there may also be one for adjusting the local oscillator frequency. ( you would also need a good selection of MOSFET’s amplifier chips)

The only way to get a better signal is to use some very good low noise floor LNB’s (.1, .2, .3 (the lower the better)) or a bigger dish, for about every 3” of diameter increase of the dish (33”, 36” 39” ect) will give you about 1.5 dB of improved signal gain.

A prime focus dish will give you more gain to a single LNB then a dish designed for 2 or more LNB’s, (the overall signal is spread out to cover both (or more)LNB's) trying to use more then 1 LNB on a prime focus dish can put one or both LNB’s out of the maximum signal area of its design.

You have stated that you have disassembled one of the LNB’s, if you look at it you will see a cone shaped piece, this is the focusing cone, the lower diameter of the cone is the final size of the focus point for that dish, the parabolic design of the dish is engineered to collect as much singal as possible and direct it down this cone to the little antennas on the LNB PCB.

These antennas are 1/2 wave stubs, they are designed for mid-band operation and should not be lengthen or shortened as this will decrease the overall received signal.


OOppppss
Sorry........... too much coffee again, I’m rambling again........sorry.....................my fault....

[ob111]

wow being a millwright, having read a few electronics books
and having played around with a few home electronics kits
that actually made some sense
I remember reading a handbook many years ago (like 20)
and I remember MOSFET (metal–oxide–semiconductor field-effect transistor)
I had to pull that out of the useless knowledge side of my brane
I used to have lots of them I could check the junk drawers
I will check out the link and see what I can come up
thanks guys