C-Band doesn't work ?

[Rockin' Rick]

Could I be the only one in here that has tried it?

C-Band doesn't work. I've tried it with 1.1G and H.
Always no signal.
Verified all my equipment, all fine. Version .87B on the same computer using the same card work.
Checked Diseqc settings.
I have currently 1.1H running, no Diseqc, only 1 satellite selected.
Card is slaved to another receiver, LNB power is not a factor.

FSS Ku works fine.

Anyone else? Or should I move this post to the bug section?

[rel]

some twinhan firmares seem to have hardcoded LOF values for Ku band (Universal LNB)

I will try to make a workaround producing equivlent C band IF using hardcoded Ku Values.

[Rockin' Rick]

Ok, did a little more experimenting.

It doesn't appear that its a firmware thing.

I can tune N.A. FSS or DBS without a problem, and can mix them using Diseqc.
I have 10750 and 11250 LOs on a 4 port Diseqc, that plays nice.

Trying to tune 3740 (C-Band transponder 2)

3740 - 5150 = -1410 (C-Band is upside down)
So 1410+10750=12160
Tuning 12160 and a LO of 10750, with C-Band LNB attached works perfectly.

Or 10373 - LO of 8963 (arbitrary value) = 1410
This works too.

I can plug in any LO value, do the math, and it tunes.

6740 - 5330 = 1410

To make sure I'm performing a valid test, another transponder...
Tuning transponder 6 at 3820:
I tried another arbitrary LO value of 4670
6000 - 4670 = 1330 L band for 3820
Works perfectly

Don't these cards tune only the L-Band frequency you tell them to?

Tuning L-Band 1270
Chose LO 10 and Freq of 1280 ->works

Could this be a problem with subtracting the LO from the desired freq. producing a negative number? Need to subtract frequencies from LO 5150 to produce positive L-band number? Or change the sign when LO exceeds desired freq.

[rel]

possible, must have a look at the calculation routine for C band values

thanks

[fundom]

Rockin' Rick, the correct way to CHANGE C-Band frequency value so as to let these work with Ku-band settings is as under:

5150- MINUS- C-Band frequency - PLUS- 9750
EXAMPLE:

5150 - 3700 = 1450 + 9750 = 11200
Now if you use this 11200 with your Ku-band settings...you will receive the channels of C-band frequency of 3700.

I have used this conversion for years for programs which did not provide settings for C-band.

[Rockin' Rick]

Fundom:
Not a problem. I can always calculate whatever I'm looking for into the actual L-Band value.

I'm just guessing that DD isn't handling the sign in the math correctly.
With Ku, the LO being greater than the desired frequency, subtracting the freq from LO always yields a postive number.
But with C-band that LO is greater than the freq so you'd get a negative number unless you flip the order or flip the sign.

With analog demodulation, depending on video stages in the equip, you have to place an inverter in the path for either C or Ku. That was a "trick" with older analog gear built for C only. They would sometimes have an option to turn on a video inverter. You could connect it to Ku and still make a picture.
I still have some of that old stuff. 70Mhz IF LNA equipment, variable frequency tuning knob. I have 2 Pinzone 70Mhz receivers in use on a Vertex 6 meter dish.