1.  Motivations

I recently tore down several inexpensive LNBs in order to select models suitable for specific modifications and applications such as:

  • Installing a crystal with a slightly different frequency. This may help receive the amateur 3 cm band with off-the-shelf DVB receivers.

  • Replacing the crystal with a more accurate TCXO or OCXO. This is convenient for receiving narrow-band transmissions.

  • Using an external clock reference. This may be useful for radioastronomy applications.

  • Injecting power without a bias tee.

These concerns are mostly about mechanical construction and ease of access to key components. RF performance was not considered at all.

Hopefully these notes and pictures will be of interest to others:

  • Radio amateurs with unusual requirements may find this information useful to choose among an abundance of models, as the first amateur 3 cm geostationary relays are expected to be deployed soon.

  • Those trained in the dark art of microwave engineering may be entertained by the fascinating variety of microstrip patterns found inside these devices.

  • Mass-market product designers may find it interesting to identify all the small decisions which ultimately lead to significant price differences between models with mostly identical specifications.

2.  Related work

There is a long tradition of adapting mass-market LNBs for amateur radio, starting probably with U.S. C-band TVRO equipment in the late 1970s. Articles can be found in amateur radio journals.

One popular online resource with information about other LNBs is https://uhf-satcom.com/blog/ku-band-pll-lnb-s.

3.  Background information on LNBs

3.1.  "Universal" LNBs

All LNBs examined here are of the so-called European "Universal" type, i.e. they can receive all four sub-bands resulting from combinations of two polarizations (horizontal / vertical) and two frequency ranges (low / high). In the U.S. they are sometimes called "LNBF" (LNB and Feedhorn), possibly because early C-band equipment had separate horns and LNBs.

Technically their frequency coverage is mostly in X band (8..12 GHz), but the fixed-satellite service in Europe is commonly considered to be an extension of Ku band (12..18 GHz). Hence, these products are marketed as "Ku-band LNBs".

3.2.  Single / Twin / Quad / Octo / Quattro

A "Single" LNB is powered through the same F-type coaxial connector that carries its output signal. It provides one of the four sub-bands depending on the DC component and optional overtone in the power supply:

  • 13 V selects vertical polarization.

  • 18 V selects horizontal polarization.

  • No overtone selects the low range, 10.70..11.70 GHz, downconverted to 950..1950 MHz by mixing with a 9.75 GHz L.O.

  • A 22 kHz overtone selects the high range, 11.70..12.75 GHz, downconverted to 1100..2150 MHz by mixing with a 10.60 GHz L.O.

A "Twin" LNB has two F-type connectors and behaves like two independent "Single" LNBs. If one of the connectors does not receive power, it will not output an I.F. signal.

A "Quad" LNB is like a "Twin" LNB, except with four independent outputs. Similarly, an "Octo" LNB offers eight independent outputs.

A "Quattro" LNB ouputs all four sub-bands, each on a dedicated connector. As long as at least one connector receives power, all four outputs are active.

3.3.  Dimensions

Most LNBs have a 40 mm diameter neck that fits inside a bracket attached to the dish.

"Bullet"-style LNBs are intended for multi-satellite setups in which two or more horns must be packed tightly in the focal region of a single dish. They typically have a 23 mm diameter neck and a narrow dielectric waveguide instead of a wide horn.

3.4.  Local oscillator

Mainstream LNBs generate their L.O. frequency either with a dielectric resonator oscillator (DRO) or with a crystal-driven phase-locked loop (PLL). PLLs are generally preferred due to their better frequency stability (about 25 kHz vs 250 kHz). However, both technologies exhibit significant temperature-dependent frequency drift.

3.5.  Noise factor

Most manufacturers claim a N.F. of 0.1 dB, which is commonly regarded as unrealistic.

3.6.  Output power

There are reports that some LNBs can output as much as 20 dBm (100 mW) under saturation. This can be a concern when connecting directly to some receivers.

Table 1.  Maximum rated input power for popular SDR receivers

PlutoSDR2.5 dBm
R820T (RTL-SDR)10 dBm
LimeSDR12 dBm

4.  General findings

4.1. PLL / DRO

All modern inexpensive "Single" LNBs turned out to be PLL-based, even those not explicitly advertized as such. No TCXOs were found - only inexpensive crystals.

Surprisingly, some "Twin" and most "Quattro" models still use DROs. It is unclear whether there is a technical reason for this, or whether manufacturers have not refreshed their product lines yet because the market for these models is smaller.

4.2. Construction

Most models are very similar in construction. Inside a plastic shell, a cast metal body forms the waveguide and cavities for one or more circuit boards. H and V probes extend from a PCB into the waveguide, one straight, one with a 90° bend.

Only a few models stand out with conductive mesh gaskets, weatherproof plastic shells, fine-threaded screws, or unusual mechanical configurations.

Some models have two layers of shielding: a cast metal cover on the microwave sections of the PCB, and a thin soft-iron lid for whole electronic cavity. The flexible lid clips between the walls of the chassis. On the one hand, this creates a good continuous RF seal. On the other hand, these lids are hard to remove, event after scrapping the sealing compound.

4.3.  RF circuits

Despite a variety of board layouts and dimensions, the circuits are also very similar. The pictures below are scaled to about 40 µm per pixel (click on thumbnails for full size) and oriented so that signals flow generally from left to right. Areas without solder mask are microwave sections. The probe connections are recognizable as large solder blobs in the left half of the pictures. From there, signals go through one, two or three stages of transistor amplification, and then into a mixer. Mixing is typically done inside the PLL IC; DRO-based models mix with transistors instead. Depending on the LNB type (Single/Twin/Quad/Quattro), one or more I.F. signals are selected, filtered and output via decoupling capacitors. Solder blobs on the right side lead to the F-type connectors.

Microwave sections are usually surrounded with ground traces that match the inner walls of the cast metal cover. DRO cavities are always heavily shielded.

The unlabeled grey pads in higher-end models are RF absorbers; they prevent self-oscillation and/or improve shielding between sections.

Some models have an IC near the first stage - presumably a bias voltage controller for the FET transistors.

A few models have a crystal with through-hole pins, on the other side of the PCB. Surface-mounted crystals are easier to replace.

The following ICs appear to be popular:

  • "3566".  Found in almost all the low-cost models. 25 MHz PLL.

  • RDA 3565ES.  Found in higher-end models. 27 MHz PLL, mixer, bias controller.

  • Rafael Micro RT320M Found in one recent design. 25 MHz PLL, twin mixer.

  • NXP TFF1015HN A 2011 IC found in one low-cost design. 25 MHz PLL, mixer. Full datasheet available, but EOL.

4.4.  Power supply

Power from the coaxial connectors goes through a thin wiggly line to a voltage regulator, and also to RC networks for 13/18 V and 0/22 kHz detection.

All models use linear voltage regulators, typically 78x06. Only one model was found to run at 3.3 V. Current ratings give an indication about the maximum consumption of the LNB and/or the derating factor that the designers chose to apply:

  • 78L06: 100 mA

  • 78N06: 300 mA

  • 78M06, 78D06: 500 mA

4.5.  Concluding remarks

A few circuit boards are obviously derived from the same reference design, which is a good thing considering the expertise that goes into a microstrip board. Still, the variety of designs is surprising for a class of products with standardized specifications. No two models turned out to be rebranded clones of the same OEM product, at least not within the same geographical market.

In general, sales prices appear to reflect the complexity of the designs. It is intriguing that LNBs can be had for only a few euros, or even 1 USD if you order a whole shipping container. The cost of the LNB is almost negligible in a satellite installation; for most consumers, it is certainly wiser to invest in a quality LNB than to climb on one's roof every few years to replace cheap units.

5.  Future work: High-end models

Only LNBs costing 20 EUR or less were considered here. Maybe higher-end models use completely different components families and construction techniques.

The following features can be found in more expensive devices:

  • C120 mounting flange for feedhorns with non-standard F/D ratios

  • Optical fiber output

  • N or SMA connectors

  • Better oscillator (1 ppm)

  • Extended temperature range (-20..+70°C)

  • "Wideband" output (downconverting 10.70..12.75 GHz to 300..2350 MHz with a 10.40 or 10.41 GHz L.O.)

  • Input for external clock reference.

6.  LNB tear-downs

Table 2.  Main characteristics

BrandModelTypeNeckCrystalPLL/MixerSource
   (mm)(MHz) (affiliate links)
Octagon OSLO 1609 Single40253566Q EQ84 Amazon Amazon
McLean MCTV-668 Single4025JVLB LN5H 8G Amazon Amazon
Opticum LSP-02G Single40253566E NQ819 Amazon Amazon
Opticum Robust Single4025T1015 04 04 SD522 Amazon Amazon
Diesl Universal Single Single40253566E NQ703 Amazon Amazon
4TV 4TV HD Single40253566E EP547 AliExpress
SuperHDsat SR-320 v1 Single40253566E DQ693 AliExpress
Star Com SR-320 v2 Single40253566E DQ693 AliExpress
BWEI BT-180 Single40253566E EP787 AliExpress
Philips SX1019 Single40(DRO)Microstrip ? Diode ? 
HD-Line HD-BP2 Twin4027RDA 3565ES (x2) Amazon Amazon
Megasat Multifeed Twin23(DRO)XH8 (x4) Amazon Amazon
Octagon OTLSO 1306 Twin4027RDA 3565ES (x2) Amazon Amazon
Octagon OTLSO 1609 Twin4025RT320M Amazon Amazon
Pro-Line P-40 Quattro40(DRO)XH8 (x4) Amazon Amazon
Venton EXL-Q Quattro23(DRO)XH8 (x4) Amazon Amazon

6.1. Octagon OSLO 1609

(Click image to enlarge)

Affiliate links

This is an inexpensive model with a simpler design than its "Twin" variant (OTLSO).

There are reports of an earlier version labeled "1301". It uses a RDA3650M and is identical to the Avenger PLL321S.

Links:

Table 3. Octagon OSLO 1609 data

TypeSingle 
Unit price (approx)8EUR,USD
Neck diameter40mm
Neck length30mm
Aperture diameter~50mm
Cap diameter62mm
Rated noise factor0.1dB
Rated gain65dB
PCB size35x21mm²
Stage 1103 (x2) 
Stage 2103 
Crystal25.000H628 
PLL/mixer IC3566Q EQ84 
Regulator78N06G 
Screws3 
RF pads1 
LabelsCE, WEEE 



6.2. McLean MCTV-668

(Click image to enlarge)

This is an intriguing model with an unidentified PLL/mixer IC running at 3.3 V. The through-hole crystal is mounted on the back side.

Table 4. McLean MCTV-668 data

TypeSingle 
Unit price (approx)6EUR,USD
Neck diameter40mm
Neck length28mm
Aperture diameter~47mm
Cap diameter53mm
Rated noise factor0.1dB
Rated gain65dB
PCB size35x19mm²
Stage 1V84 (x2) 
Stage 2V84 
Crystal25.000M08 
PLL/mixer ICJVLB LN5H 8G 
Regulator78L33 
Screws2 
LabelsCE, WEEE 



6.3. Opticum LSP-02G

(Click image to enlarge)

This a basic model, compact and inexpensive.

Table 5. Opticum LSP-02G data

TypeSingle 
Unit price (approx)6EUR,USD
Neck diameter40mm
Neck length30mm
Aperture diameter~40mm
Cap diameter50mm
Rated noise factor0.1dB
Rated gain60dB
PCB size31x25mm²
Stage 1V75 (x2) 
Stage 2V75 
CrystalJWT25.000 
PLL/mixer IC3566E NQ819 
Regulator78S06M 
Screws3 
LabelsCE, WEEE 



6.4. Opticum Robust (Amiko L-107)

(Click image to enlarge)

This model has a small non-rectangular circuit board. The through-hole crystal is mounted on the back side.

The PLL/mixer is a NXP TFF1015HN.

Apparently sold as Amiko L-107 in the U.S.A.

Table 6. Opticum Robust data

TypeSingle 
Unit price (approx)6EUR,USD
Neck diameter40mm
Neck length36mm
Aperture diameter~50mm
Cap diameter56mm
Rated noise factor0.1dB
Rated gain dB
PCB size47x22mm²
Stage 1V75 (x2) 
Stage 2FX 
CrystalJ25F6S8 
PLL/mixer ICT1015 04 04 SD522 
Regulator  
Screws3 
LabelsCE, WEEE 



6.5. Diesl Universal Single

(Click image to enlarge)

Affiliate links

This is a basic model, compact and inexpensive, but with interesting microstrip patterns.

Table 7. Diesl Universal Single data

TypeSingle 
Unit price (approx)6EUR,USD
Neck diameter40mm
Neck length26mm
Aperture diameter~50mm
Cap diameter60mm
Rated noise factor0.1dB
Rated gain dB
PCB size28x24mm²
Stage 1103 (x2) 
Stage 2103 
CrystalZC25.000 
PLL/mixer IC3566E NQ703 
Regulator78L06 
Screws4 
RF pads1 
Labels  



6.6. 4TV 4TV HD

(Click image to enlarge)

Affiliate links

This is a basic model with the distinguising feature that the cast metal enclosure is not sealed. Instead, the plastic shell is weatherproof (and hard to open). Also, the F-type connector is attached to the cover rather than to the main body.

Table 8. 4TV 4TV HD data

TypeSingle 
Unit price (approx)4EUR,USD
Neck diameter40mm
Neck length mm
Aperture diameter~36mm
Cap diameter56mm
Rated noise factor0.1dB
Rated gain60dB
PCB size27x22mm²
Stage 13513 FK46 (x2) 
Stage 23513 FK46 
CrystalJ25.000M 
PLL/mixer IC3566E EP547 
Regulator78L06 
Screws2 
LabelsCE 



6.7. SuperHDsat SR-320 v1

(Click image to enlarge)

Affiliate links

A ultra-low-cost model. The unit I examined had a missing screw hidden by the sealant compound. No CE mark.

There is a different model also branded as "SR-320" (see below).

Table 9. SuperHDsat SR-320 v1 data

TypeSingle 
Unit price (approx)3EUR,USD
Neck diameter40mm
Neck length30mm
Aperture diameter~40mm
Cap diameter60mm
Rated noise factor0.1dB
Rated gain65dB
PCB size47x15mm²
Stage 110F (x2) 
Stage 210F 
Crystal25.000 
PLL/mixer IC3566E DQ693 
Regulator78L06 
Screws3 
Labels  



6.8. Star Com SR-320 v2

(Click image to enlarge)

Affiliate links

This is a ultra-low-cost model. The through-hole crystal is mounted on the back side. The unit I examined had insufficient sealing. No CE mark.

Table 10. Star Com SR-320 v2 data

TypeSingle 
Unit price (approx)3EUR,USD
Neck diameter40mm
Neck length27mm
Aperture diameter~48mm
Cap diameter61mm
Rated noise factor0.1dB
Rated gain dB
PCB size34x14mm²
Stage 110x 
Stage 210T 
CrystalEE25.000M 
PLL/mixer IC3566E DQ693 
Regulator78L06 
Screws2 
Labels  



6.9. BWEI BT-180

(Click image to enlarge)

Affiliate links

This is a ultra-low-cost LNB, with a plain layout but otherwise using the same components as the others. Comes unbranded and without a CE mark.

Table 11. BWEI BT-180 data

TypeSingle 
Unit price (approx)2.5EUR,USD
Neck diameter40mm
Neck length42mm
Aperture diameter~50mm
Cap diameter60mm
Rated noise factor0.1dB
Rated gain58-65dB
PCB size35x22mm²
Stage 1V75 (x2) 
Stage 2V75 
CrystalH25.000M-20 
PLL/mixer IC3566E EP787 
Regulator78S06 
Screws4 
Labels  



6.10. Philips SX1019

(Click image to enlarge)

Affiliate links

This is a historical model made in Germany, possibly in the late 1990s or early 2000s. The plastic shell is weatherproof and welded around the F-type connector. The thin circuit board is riveted between the main body and a backing shield. Probes are apparently gold plated and held in place by PTFE washers. The main IC is a ZNBG3113 bias controller and I.F. switch.

Table 12. Philips SX1019 data

TypeSingle 
Unit price (approx)?EUR,USD
Neck diameter40mm
Neck length40mm
Aperture diameter47mm
Cap diameter59mm
Rated noise factor?dB
Rated gain?dB
PCB size84x25mm²
Stage 1"G" (x2) 
Stage 2"G" 
Stage 3"G" 
CrystalDRO + T79 (x2) 
PLL/mixer ICMicrostrip ? Diode ? 
Regulator8C3Q 
RF pads2 
Rivets11 
LabelsCE 



6.11. HD-Line HD-BP2

(Click image to enlarge)

This is a sophisticated design with a nice symmetrical board layout. A single crystal apparently drives the two PLL/mixer ICs. There is free space in the enclosure near the gold-plated output connectors.

Table 13. HD-Line HD-BP2 data

TypeTwin 
Unit price (approx)20EUR,USD
Neck diameter40mm
Neck length56mm
Aperture diameter mm
Cap diameter59mm
Rated noise factor0.1dB
Rated gain62dB
PCB size73x24mm²
Stage 13Y C A205 (x2) 
Stage 2V84 (x2) 
Stage 3t7N (x4) 
CrystalH27.000M 
PLL/mixer ICRDA 3565ES (x2) 
Regulator78S06M (x2) 
Screws6 
LabelsCE, WEEE 



6.12. Megasat Multifeed

(Click image to enlarge)

This is a "bullet"-style LNB with a narrow head and 23 mm diameter neck followed by a 40 mm diameter section. The two circuit boards are quite sophisticated, but use DROs. Four transistor-based mixers feed into an AMICCOM A7533 switch.

Table 14. Megasat Multifeed data

TypeTwin 
Unit price (approx)17EUR,USD
Neck diameter23mm
Neck length31mm
Aperture diameter mm
Cap diameter30mm
Rated noise factor0.1dB
Rated gain dB
PCB size91x25 + 37x26mm²
Stage 153 C A042 (x2) 
Stage 2DW (x2) 
Stage 3DW (x2) 
CrystalDRO + NDt (x2) 
PLL/mixer ICXH8 (x4) 
Regulator78M06 
Screws9 
RF pads20 
LabelsCE 



6.13. Octagon OTLSO 1306 (Amiko L-203)

(Click image to enlarge)

Affiliate links

This model is popular in the amateur radio community. The second PLL/mixer is in a dedicated shielded cavity.

Apparently sold as Amiko L-203 in the U.S.A.

Links:

As of October 2018, this model can still be found in the supply chain, but a completely redesigned variant is being rolled out with the same product name and SKU (see OTLSO 1609 below). "1306" and "1609" refer to markings near the CE logo on the sticker. There is also a "1301" variant which is largely identical to 1306; maybe these are merely production date codes.

Table 15. Octagon OTLSO 1306 data

TypeTwin 
Unit price (approx)15EUR,USD
Neck diameter40mm
Neck length54mm
Aperture diameter~50mm
Cap diameter62mm
Rated noise factor0.1dB
Rated gain60..65dB
PCB size73x24 + 36x24mm²
Stage 129 C A373 (x2) 
Stage 2V75 (x2) 
Stage 3V75 (x4) 
Crystal27.000 (x2) 
PLL/mixer ICRDA 3565ES (x2) 
Regulator78H06 (x2) 
Metric screws5+3 
RF pads8+7 
LabelsCE 



6.14. Octagon OTLSO 1609

(Click image to enlarge)

Affiliate links

This is a redesign of the OTLSO, identified by "1609" near the CE mark on the sticker. Only two stages of transistor amplification, twin-mixer IC, 25 MHz crystal instead of 27 MHz. The board layout is simple and elegant thanks to the dedicated Rafael Micro IC, although it has obviously been tailored to fit in the same cast metal enclosure as the earlier variant.

Table 16. Octagon OTLSO 1609 data

TypeTwin 
Unit price (approx)15EUR,USD
Neck diameter40mm
Neck length54mm
Aperture diameter~50mm
Cap diameter62mm
Rated noise factor0.1dB
Rated gain60..65dB
PCB size72x23mm²
Stage 1FET (x2) 
Stage 2103 (x2) 
Crystal25.000H629 
PLL/mixer ICRT320M 
Regulator78N06G (x2) 
Metric screws5 
RF pads3 
LabelsCE, WEEE 



6.15. Pro-Line P-40

(Click image to enlarge)

Affiliate links

A sophisticated design with RF gaskets and two layers of shielding, but with DROs rather than PLLs. Four transistor-based mixers feed into a dedicated PCB with the Quattro outputs.

Table 17. Pro-Line P-40 data

TypeQuattro 
Unit price (approx)18EUR,USD
Neck diameter40mm
Neck length37mm
Aperture diameter mm
Cap diameter62mm
Rated noise factor dB
Rated gain dB
PCB size65x24 + 32x28 + 30x65mm²
Stage 168 C A103 (x2) 
Stage 2B7 (x4) 
CrystalDRO + NEt (x2) 
PLL/mixer ICXH8 (x4) 
Regulator78D06L 
Screws4 
Metric screws6 
LabelsCE 



6.16. Venton EXL-Q

(Click image to enlarge)

Affiliate links

A sophisticated "bullet" model with two layers of shielding, but with DROs rather than PLLs. It has a short 23 mm diameter neck followed by a 40 mm diameter section. Interesting use of some kind of ink to tune one microstrip pattern.

Table 18. Venton EXL-Q data

TypeQuattro 
Unit price (approx)14EUR,USD
Neck diameter23mm
Neck length22mm
Aperture diameter mm
Cap diameter30mm
Rated noise factor0.1dB
Rated gain dB
PCB size101x25 + 37x28mm²
Stage 161 C A113 (x2) 
Stage 2V75 (x4) 
CrystalDRO + T79/GG (x2) 
PLL/mixer ICXH8 (x4) 
Regulator78M08 
Screws9 
RF pads13 
LabelsCE 



7.  Terms of use

It took a lot of work to compile these notes and pictures. You may not republish them in bulk without permission. However, you may republish up to two photographs, with optional annotations, under the condition that you include a hyperlink to this web page, http://www.pabr.org/radio/lnblineup.

PCB layouts remain the property of their authors. They are discussed here for educational purposes only.