lnb modification

J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
Hi everybody,im quite new to this forum ,i have afew questions for the teckies ,i used to install systems back in the analogue days ,i spend 10 weeks each year in costa blanca ,over there the only way to receive freesat or any uk tv, is with a1.9 mtr dish or a 60cm dish just for south beam [very limited choice] .
not every one there has the space to fit a large dish ,so a lot of companies have set up rebroadcast systems [they buy a licence to rebroadcast in spain] i have swung a small dish towards their mast and recieved signals but they must either be using circular polarised lnbs or are using lower local osc frequency lnb.i know these sigs are unencrypted as i borrowed my neighbours lnb, and with a full scan of my fta receiver bingo !
question; any ideas what mod they may have done to the lnb?
maybee inserted dielectic plate inside feedhorn?
i tried all the sat shops but they couldnt help the lnb looks just like a normal uni but with no markings on it any thaughts please:confused
 
A

A nonymous

Member
Messages
3,586
It might sound stupid but if you think they are circular polarity lnbs you could always try an old BSB squarial :eek:

The other place to find them would be on ebay.com (The yank site) as they still use circular polarity in the USA :D
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
yes i looked on American sites at all the circular types ,hoping i would see one that looks the same [with the same casing ] but no joy it looks for all the world lihe a common uni single o/p type inside there were no numbers only a serial number 0809783a02766,there were no trimmers inside for l/o freq ill have a look for a squarial type thanks
 
Topper

Topper

Amo Amas Amant Admin
Staff member
Messages
23,137
My Satellite Setup
IDD CI24 ECONO MM Penta 1.20 Galaxy II
1.2Mtr Polar MTG yes it has been on the arc for 25 years and is now fixed on 13 East using two pairs of rusty molegrips. Unlike me they never groan but always perform.
My Location
Blackburn, Lancashire
Don't know why are you bothering when the systems are regularly being taken down by the Spanish authorities?
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
yes a lot of the dodgy non tax paying rebroadcasters have been locked up by the guarda civil they dont mess around,
but the ones that are registered in Spain are still allowed to transmit
its a bit of a lottery, many ex pats have been ripped off.the best ones provide tv for norweigans,as well as the brits , who otherwise would need JODERAL bank on their roof 1;)
 
ralphmagno

ralphmagno

Regular Member
Messages
994
My Location
naples italy
hello the lnb can be adjusted no problem.
but what frequency will you be reciving?
the osc can be adjusted by about 90 mhz.
if they were transmitting on a frequency of 10660 ghz your receiver will not tune below 10.750 so moving the lo to 09.660 ghz and bingo the receiver will receive a frequency transmitted below the satellite band by 90 mhz.
the receiver will say 10.750 even though you are receiving a signal at 10.660.
they are probaly using hor or vert polerazion.
this is like a mmds system and without the ofset on the lo no one will pick this up.
a 1 watt transmitter will at 10.6 ghz will go 20 km line of site with a 30 cm dish and 30 km witha 60 cm dish.
if you know the frequency it would be easier.
i have modified 100 lnbs like this.
the f-wave is the easiest

ralph:)
 
slugworth

slugworth

Regular Member
Messages
153
My Satellite Setup
gsky v7
My Location
New England
The dielectric plate is just non-microwave safe plastic,the kind that heats up and melts in a microwave oven.
In the colonies people use old credit cards cut to fit the lnb throat.
I have used milk bottle plastic and plastic lids from coffee cans,but you have to double up the plastic strips if too thin.
Stick in the lnb throat at the 1 o'clock position relative to the probe inside.
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
hi i believe they transmit on 9.54ghz this is received on a 30 cm dish pointed towards the horizon, the lnb that is supplied when opened,has no trimmers to adjust l/o freq ,i tried a standard uni and tweeked the trimmers slowly with sig strength meter,
i still could not receive the sigs ,this led me to think they must modify feed horn any thaughts ?
 
Huevos

Huevos

Satellite Freak
Messages
5,995
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
I can't believe that is anything but a universal LNB.
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
hi very informative reply thanks ralph magno is the F WAVE a type of lnb ?if so who makes them? another interesting point the system requires no skew of the lnb but when i rotated it beyond 90 degrees the sig went up?
most uni lnbs i/p freq is 10.7ghz to 11.7ghz this means that if i tweek the trimmer i still cant reduce the freq low enough any thoughts please
 
Huevos

Huevos

Satellite Freak
Messages
5,995
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
Just a thought. If the transmitter were really broadcasting on 9.54GHz and you set the receiver to l.o. 10.6GHz (i.e. hi band) the IF would be on 1.06GHz, well within the receivable range of the box with a standard universal LNB. This is not the case though as all the ones I've seen are tuned to lo-band, somewhere around 10.7GHz if I remember right.

How about doing a test the other way around? Stick the possibly modified LNB on a dish pointed at a satellite and see how it works. This would prove whether it is modified or otherwise.
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
hi thanks for reply ,i tried that i have a dish set for 28.2 astra
it receives south beam with standard uni lnb ,
when i tried the modified lnb i got no signals ?:mad::confused
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
hi being new to the forum im not yet allowed to post pm[ private messages]
i want to contact Ralph magno as he seems to have the answer to my problem.if you read this Ralph can you e mail or pm me please ,i would like some more info re lnb l/o mods MANY THANKS JIM
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
30,432
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
Huevos said:
Just a thought. If the transmitter were really broadcasting on 9.54GHz and you set the receiver to l.o. 10.6GHz (i.e. hi band) the IF would be on 1.06GHz, well within the receivable range of the box with a standard universal LNB. This is not the case though as all the ones I've seen are tuned to lo-band, somewhere around 10.7GHz if I remember right.

Unless I have read your post incorrectly, a digital stb with a functioning Local oscillator setup will not work to receive a lower working frequency than the local oscillator it is set up to use, unless are working at C-Band.

Since these are normally set to 5.150GHz, you could always programme this into the receiver, and then scan with a standard unversal LNB (set to the upper band with the 22kHz switch) around the frequency of 4.09 GHz.
 
T

Tsiklon

Regular Member
Messages
88
My Satellite Setup
Various
My Location
Europe
Perhaps the OP could post a photo of the LNB used by his neighbour?

He could also figure out what the LO of the modified LNB is by doing a blindscan on 19e with the modified LNB and calculating the difference between the recorded freq and the published freq on lyngsat.

I've only ever heard of terrestrial transmission of television channels in the Ku band, but never below 10.7 GHz in the 9GHz region.


[TUBE]sm9ZgvX2aEk[/TUBE]
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
Thanks Channel hopper i never thought about c band ,its just that my neighbour who has this system
i borrowed his lnb just to try and after a full scan on my fta receiver bingo all signals received.
i did not have to alter my fta settings to c band , all sigs received i then began the QUEST of finding out what was different with this lnb .
A standard lnb will pick up some sigs but not them all SO ;
its either lower l/o freq ? possibly around 9ghz
dielectic plate inside feedhorn?
or something else ,possibly sourced from USA for circular polarisation?
any thaughts:confused
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
30,432
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
jimbofz said:
Thanks Channel hopper i never thought about c band ,its just that my neighbour who has this system
i borrowed his lnb just to try and after a full scan on my fta receiver bingo all signals received.
i did not have to alter my fta settings to c band , all sigs received i then began the QUEST of finding out what was different with this lnb .
A standard lnb will pick up some sigs but not them all SO ;
its either lower l/o freq ? possibly around 9ghz
dielectic plate inside feedhorn?
or something else ,possibly sourced from USA for circular polarisation?
any thaughts:confused
A circular polarised chanel will be approximately 4dB down if using a non circular LNB and so I would not expect this to be the reason for no detection.

Unless your neighbour has a hugely modified LNB (with something like an 8GHz local oscillator), I can only suggest you try the C-Band trick and let us know what happens, however, if this was the case, then there would be no need to offer modified LNB's in the first place. Are you certain 9.54 GHz is correct ?
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
thanks again channel hopper this thread seems to be quite old and things have moved on ,the old systems rebroadcast analogue with a wire mesh square aerial and downconvertor the new guys use 30 cm dishes and the MYSTERY LNB
 
J

jimbofz

Member
Messages
44
My Satellite Setup
fta 1.4mtr dish
My Location
uk and spain
i was told by a local sat installer that they used this freq he seemed pretty certain cheers ps love the logo septic resident
 
Top