a quick guess would suggest that the dro in your c-band lnb is the fault as its harmonically related to this area of frequencys
have seen it before probablly water ingress
I don't have any testing equipment but I use my PC with a TBS 6902 tuner with EBS Pro software, if I do a RF SCAN i can see a very high peak -37dBm on both V/R and H/L between approx. 3612Mhz till around 3648Mhz on all Satellites. This seems like local interference to me. Does anyone know what typical local service that might cause this freq to the swamped?
Without having to relocate the dish, is there any cheaper fix that will reduce this what seems to be local noise?
I know you can buy C Band LNB's that only cover the 3700Mhz - 4200Mhz band and these days a lot of signals seem to be in that range. But I do get some good results in the 3400Mhz -3699Mhz range so I am not keen on cutting out that area.
I have noticed that some LNB's mention 4G filtering (but still cover the extended Cband range of 3400Mhz - 4200Mhz) would replacing the LNB help in this area, or is the only way is to filter out those effected freqs?
I have a feeling there isn't much I can do and will have to live with it.
Last edited by backer; 27-05-18 at 11:39 AM.
Look Here -> |
a quick guess would suggest that the dro in your c-band lnb is the fault as its harmonically related to this area of frequencys
have seen it before probablly water ingress
backer (28-05-18)
It showed this issue right out of the box the day the LNB was installed.
When the installer was configuring with his meter I asked him what was that peak and he said noise
I guess it couldn't hurt replacing it, but can any one suggest a reasonable priced one less than $100?
I just didn't want to spend if the result would be the same, local noise that I couldn't really control.
Last edited by backer; 27-05-18 at 05:28 PM.
Sounds like it could be the LNBF or yeah just local noise what LNBF are you using?
I hear Kaonsat LNBF's are really good for this region.
If your C-band LNB is the 13/18Volt V/H switching type and both the V and H antenna probes inside the LNB throat receive the same level of noise then its more then likely an issue with DRO . Since about 2016, run of the mill standard C-Band LNB's produced, use PLL instead of DRO they are allot more efficient, stable and cost the same as the old DRO type. Be aware that most LNB although new in the box are old stock. Because of the massive decline in demand sellers are straggling to clear their old stock. therefore only a few sellers would have them.
can you get hold of a spectrum analyser
then you can see if its on the actual frequency or the if that you are looking at
it may be that its not on the fundemental only showing up on the if .
therefore its not local interference it s a gear fault , good luck
backer (28-05-18)
Yes it's the stock standard V/H switching 3.4-4.2 C Band 13/18 Volt. And yes the noise level around the same freq is the same for both V and H pols.
Can you recommend a seller that has the PLL type?
I know there are professional ones that cost hundreds I just want a reasonable priced switching one that covers the extended C band. The run of the mill ones dont tend to say DRO or PLL.
What about the Stong SRT L928 ?
Last edited by backer; 27-05-18 at 06:34 PM.
I've heard the Strong are good, if you can find a reasonably priced Norsat one they're defiantly the best though.
Norsat 5250R perhaps
Last edited by nullb; 27-05-18 at 06:48 PM.
backer (28-05-18)
If it is local interference in the frequency range you want, filtering the offending signals will also filter out what you want.
Which suburb are you in?
I'm in Melbourne near Chadstone
Any recommendations on a replacement LNBF on a low priced but slightly better performance model? Any PLL designed ones that are affordable , all I can see are the ones that are $150+. Unless they are more expensive they don't usually say if they are PLL based.
Also I note some of them are a different shape, does that mean I need some kind of professional mount to use them?
If my cheap LNBF is slightly damaged and a new affordable one improves just little bit I would be happier with that.
I was looking at this one
before you go to spending money i would suggest that you pop the top of the lnb and have a looky inside you will find a cast ally box with a screw in its middle and two holddown screws
check this area for sign of moisture if its corroded or showing whiteish its had water ingress if not then its something else the top can be put back on it and sealed with rtv , look down the throat and check that the hoz antenna is not been bent away from the choke ( this is the bigger bar that stops the vert from seeing the hoz) i have found brand new ones that this appears on , and causes harmomic parasitation. if you have any experence with working out harmonics you can do it mathmatically or just guess like i do most of the time lol
backer (28-05-18)
ps the picture you have is of the intermediate frequency ie 950mhz-2.1 ghz not the fundimental 3.?ghz understand ???
backer (28-05-18)
try ebay C-band LNBF C2W-PLL Wideband & Conical Scalar CS1 Bundle- Dual (2) Outputs LNB
Lifetime Warranty- Perfect for Offset Dish & Micro BUDs i use these
backer (28-05-18)
all different sizes some prime focus some offset ? why ?
better explain me
im a old retired broadcast tech &70 y old i use satbeams to get the general idea of the size dish required
on c band i have a old lnb with the guts cut out and only the vert antenna in it ,
this is directly connected to some rg11 that goes into my r&s f6 so i can measure the level directly
some times i use a cheepo rf amp to lift the level basic stuff is best this shows up any local interference and
has save me chasing ghosts many times ok with that ?
backer (28-05-18)
So much information. Thank you all.
I've ordered a Titanium C1W-PLL single output from ebay.
Bookmarks