Dear DX-r amateurs!
Please, If you have any type Invacom LNB-s, send to me, or post in the forum the "Actual measured Noise figure and Gain response" titles document, it's easy to read photo, or scanned in format.
That's what I thought:
My goal, that i examine, evaluate this LNB typem in NEC NEC3210S01 GF equipped noise and gain indicators.
Very thanks,
SaTom
Meinst du das Data sheet oder tatsächlich gemessene Werte.
Letztere sind etwas aufwendig und auch von anderen Faktoren abhängig.
Vor etwas über 3 jahren gab es Rauschmessungen mit dem IQMonitor.
Das Invacom hatte ich nicht getestet.
Do you mean the data sheet or actual measured values.
The latter are somewhat complex and also depend on other factors.
A little over 3 years ago there were noise measurements with the IQMonitor.
I hadn't tested the Invacom.
Hallo Satcom
Here is what I have.
AND, i will use testing the IQmonitor pro :-). (If i buyed the software.)
SaTom
IQmonitor is free, there is nothing to buy.
Two sheets without general text on the right side
Both are SNF (flange) single, 0,3dB, LOF 9,75/10,6
The text on right side is the same like on the picture which stephan94 have posted.
Quad 031
I have a problem with the camera, maybe tomorrow..
I find the noise figures quoted by non-professional suppliers most annoying. The Invacom LNBs are some of the better ones but perhaps someone can explain to me how a 0.3dB noise figure device and give 0.2dB noise figure (without using cryogenic techniques) . The noise figures quoted for devices are generally the de-embedded figures. i.e. they have all circuit losses removed by calculation. The best noise figures achieved in real-world designs are in the region of 0.7dB at room temperature and that is often for a relatively narrow band design at 10GHz.
The only LNBs that are reasonably easy to measure are standard WG types. I have found that those from the pro manufacturers generally meet their specifications. For example SMW, Norsat etc who usually quote around 0.8dB on Ku band. It's hard to measure a C120 LNB in the lab since the transition to rectangular guide is an unknown. The simplest way to measure LNB noise without test gear is to use natural sources as described here. I usually use Sun noise to test the whole system. However, Sun noise itself is variable so is of most use for comparisons made within an hour or 2 of each other. This is a good paper on natural noise.
If comparing LNBs, it's not just the NF you need to worry about, especially for modes such as 32APSK and very narrow low SR signals. For those the LO must have a low phase noise. The Invacom is actually quite good for a free running DRO. When testing using IQ monitor/Crazyscan etc, check a selection of SR and modulation types.
It may be worth trying different devices in LNBs. However, in my experience, it is hard to even keep the original performance. I repaired an SMW LNB which had a dead 1st FET and it only just managed to tweak it to 0.8dB NF using patches on the tracks. I have got down to 0.7dB, narrow band, on an 8.45GHz LNA (MGF4919G FET).
<edit> Here's a useful article from CEL. Note the final comment:
In actual product development, the design process is much more complex due to various imperfection in components/devices and constraints on circuit implementation. While the simulation shows a noise figure of about 0.5dB, a product specification of 1dB or slightly lower for noise figure is generally considered excellent when everything is taken into account. Nevertheless the considerations outlined in this note are relevant in real world applications.
"Es ist schwierig, einen C120-LNB im Labor zu messen, da der Übergang zum rechteckigen Leiter unbekannt ist."
Wie muss ich das verstehen, der Übergang vom runden zum rechteckigen Hohlleiter sitzt beim Invacom im LNB?
"It is difficult to measure a C120 LNB in the laboratory because the transition to the rectangular conductor is unknown."
How should I understand that the transition from the round to the rectangular waveguide is located in the LNB on the Invacom?
femi The rectangular to circular transitions used for C120 to WR75 are usually 1/4 wave transformers. These are not a wide band match although generally good enough for our purposes. The match and losses are important when measuring noise figure and are not defined. One can guess at the loss (probably <0.1dB) but the effect of a mis-match is hard to quantify. Anything put between the calibrated noise source and the test unit is a potential source for error.
Regarding the square to circular transition that is part of the Invacom, it does not affect our measurements as it is always present. We are interested in the noise figure of the whole thing as seen at the C120 flange. A square to circular transition is actually quite a good wide band match when compared to a rectangular to circular transition.
Die für C120 bis WR75 verwendeten rechteckigen zu kreisförmigen Übergänge sind normalerweise Viertelwellentransformatoren. Dies ist keine Breitbandübereinstimmung, obwohl sie für unsere Zwecke im Allgemeinen gut genug ist. Die Übereinstimmung und die Verluste sind bei der Messung der Rauschzahl wichtig und nicht definiert. Man kann den Verlust schätzen (wahrscheinlich <0,1 dB), aber die Auswirkung einer Fehlanpassung ist schwer zu quantifizieren. Alles, was zwischen der kalibrierten Rauschquelle und dem Testgerät liegt, ist eine potenzielle Fehlerquelle.
Der quadratische zu kreisförmige Übergang, der Teil des Invacom ist, hat keinen Einfluss auf unsere Messungen, da er immer vorhanden ist. Uns interessiert die Geräuschzahl des Ganzen, wie sie am C120-Flansch zu sehen ist. Ein Übergang von quadratisch zu kreisförmig ist im Vergleich zu einem Übergang von rechteckig zu kreisförmig tatsächlich eine recht gute Breitbandübereinstimmung. <note: I don't think 'match', meaning return loss, translates correctly>
single..
I don't have a certificate from other Invacoms..
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