Advice Needed Why dual IF LNBs?

[aceb]

A simple question for someone who knows! Why are some C-Band LNBs dual IF with 5150/5750MHz?

Edited to add.. The forum software 'feature' that strips titles of all but the initial capital letter really triggers my OCD

 

[anto@]

mono ponto multi ponto they are prevalently used for the Brazilian market in practice, on a local oscillator 5150 the vertical part 950/1450 mhz passes while the horizontal part must use the other local oscillator value and the signals go from around 1550/2100 mhz therefore on a single cable all frequencies of C band pass for multiple installations

 

[PaulR]

Edited to add.. The forum software 'feature' that strips titles of all but the initial capital letter really triggers my OCD

It's an unfortunate necessity forced upon us by the small number of people who keep their CAPS LOCK switched on.

You can get round this by going into Edit immediately after you've posted and then altering the title suitably. You need to do this pretty quickly as the right to edit your post goes after a time (not too sure how long).

Do you want to try this and see if it's still available? If not I'll change it for you.

 

[aceb]

Looks like I've missed that window Paul. No need to edit it now but I'll remember for next time, thanks for the info.

 

[PaulR]

OK. I've changed it for you. Hope you approve!

 

[aceb]

mono ponto multi ponto they are prevalently used for the Brazilian market in practice, on a local oscillator 5150 the vertical part 950/1450 mhz passes while the horizontal part must use the other local oscillator value and the signals go from around 1550/2100 mhz therefore on a single cable all frequencies of C band pass for multiple installations

This could answer another question. TEK2000 are selling this Dual Band LNB listed for circular polarisation. If each probe is only connected to one IF/band as per the original design then I guess they've re-engineered one IF for the higher band hence it only being good for circular polarity. tempting to get one and modify it for use with the AV-comm polariser.

 

[Channel Hopper]

Circular polarity is decided by the mechanical design though, since the probes inside are - almost certainly - installed at 90 degrees apart, the polarity will always be circular, regardless of frequency.

(Caveat- some dielectric material does have permittivity that is frequency dependent but not a 45 degree phase change at C band).

 

[Channel Hopper]

Looking at the LNBs spec it has a separate - removable - dielectric plate inside, tone is used for frequency shift, voltage for polarity switch.

 

[scopus]

This could answer another question. TEK2000 are selling this Dual Band LNB listed for circular polarisation. If each probe is only connected to one IF/band as per the original design then I guess they've re-engineered one IF for the higher band hence it only being good for circular polarity. tempting to get one and modify it for use with the AV-comm polariser.

Just ordered one from Ali express..worth a punt.

 

[s-band]

This could answer another question. TEK2000 are selling this Dual Band LNB listed for circular polarisation. If each probe is only connected to one IF/band as per the original design then I guess they've re-engineered one IF for the higher band hence it only being good for circular polarity. tempting to get one and modify it for use with the AV-comm polariser.

I suspect it may have the same chip as the Tit, or something similar, which has the facility to switch LO frequencies. That means it's probably a PLL. @scopus, are you sure the ones on Aliexpress are the same and not the frequency stacking ones? Do you have a link?

 

[Channel Hopper]

I suspect it may have the same chip as the Tit, or something similar, which has the facility to switch LO frequencies. That means it's probably a PLL. @scopus, are you sure the ones on Aliexpress are the same and not the frequency stacking ones? Do you have a link?

Is there a C band PLL without a heatsink ?

 

[aceb]

Yes, don't be taken in by the product number, I came up with a couple of similar items all called a PS-1210. It's not helped by the Chinese sellers who headline one frequency range then state another in the detail, sometimes showing a third variant on the LNB label!

FWIW neither the supplier of this LNB or this LNB can supply single units for evaluation. This wasn't an attempt to get one item on the cheap, I just don't trust Chinese manufacturers to supply what they show on their webpages

@scopus Do you have a link to the one you ordered? I would rather order from China than Canada because in my (work related) experience very little gets clobbered for duty and vat from China but everything does from NA.

 

[moonbase]

Yes, don't be taken in by the product number, I came up with a couple of similar items all called a PS-1210. It's not helped by the Chinese sellers who headline one frequency range then state another in the detail, sometimes showing a third variant on the LNB label!

FWIW neither the supplier of this LNB or this LNB can supply single units for evaluation. This wasn't an attempt to get one item on the cheap, I just don't trust Chinese manufacturers to supply what they show on their webpages

@scopus Do you have a link to the one you ordered? I would rather order from China than Canada because in my (work related) experience very little gets clobbered for duty and vat from China but everything does from NA.

From personal experience with Ali Baba suppliers, the prices they quote for the minimum order quantity are often incorrect and can increase when getting an actual quote from the supplier. In addition some Ali Baba vendors do not accept PayPal and require a bank transfer as payment. On Ali Express the vensors generally have the prices correctly indicated and in my personal opinion transactions are simpler via Ali Express compared to Ali Baba.

 

[scopus]

Yes, don't be taken in by the product number, I came up with a couple of similar items all called a PS-1210. It's not helped by the Chinese sellers who headline one frequency range then state another in the detail, sometimes showing a third variant on the LNB label!

FWIW neither the supplier of this LNB or this LNB can supply single units for evaluation. This wasn't an attempt to get one item on the cheap, I just don't trust Chinese manufacturers to supply what they show on their webpages

@scopus Do you have a link to the one you ordered? I would rather order from China than Canada because in my (work related) experience very little gets clobbered for duty and vat from China but everything does from NA.

I think I ordered a variation on the American one, no mention of extended range. S Band thinks they are these......
They use one LO for each polarisation and
frequency stack. i.e one pol is 950-1450 and the other is 1550-2050 so you
get both polarisations at the same time one one cable.
I have cancelled my order...