Es'hail-2 LNBs and Antennaes - Revision history

M0YDH: /* Suitable 25 MHz Reference */

2019-04-13T20:46:53Z

Suitable 25 MHz Reference

G8GTZ: /* Goobay LNB */

2019-03-03T14:32:52Z

Goobay LNB

G8GTZ at 14:32, 3 March 2019

2019-03-03T14:32:17Z

G8GTZ at 14:31, 3 March 2019

2019-03-03T14:31:15Z

M0DHP: /* Goodbay LNB */

2019-02-26T21:31:45Z

Goodbay LNB

G8GTZ: /* Phase Noise */

2019-02-02T17:37:25Z

Phase Noise

G8GTZ at 17:33, 2 February 2019

2019-02-02T17:33:56Z

G8GTZ: /* Octagon LNB */

2019-02-02T17:33:05Z

Octagon LNB

G8GTZ: /* Frequency coverage and operating out of specification */

2019-02-02T17:32:14Z

Frequency coverage and operating out of specification

G8GTZ: /* Frequency coverage and operating out of specification */

2019-02-02T17:31:45Z

Frequency coverage and operating out of specification

@@ Line 78: / Line 78: @@
 [[File:25 MHz filter.JPG|500px]]
 The low pass filter had 5 elements, 288 pf to ground on the input, a series inductor of about 10 turns on a 4 mm core, 407 pf to ground in the centre, then another identical series inductor and 288 pf on the output.
 ===Phase Noise===

@@ Line 84: / Line 84: @@
 While having a stable LO might be perfect for narrow-band operation, any increase in phase noise might reduce the apparent sensitivity for DATV.  I found that a 1MS DVB-S signal that gave 24 dB MER with the crystal oscillator only gave 21 dB MER with the external reference; this will need more investigation.
-==Goobay LNB==
+===Goobay LNB===
 To be completed

@@ Line 1: / Line 1: @@
 The LNB is the electronics placed at the dish feed which downconverts the satellite frequencies (10,700 - 12,750MHz) to L abnd (950 - 2150MHz) which is then sent down the co-ax to the satellite reciever.
 ===DC Supply===
@@ Line 9: / Line 7: @@
 The 12V or 18V LNB supply and returned signals share the same coax. A bias-T https://en.wikipedia.org/wiki/Bias_tee is needed to separate the DC from the IF but this can be very simple. Either buy one or make it using an RF choke and a DC blocking capacitor. There are some designs available elsewhere in this Wiki, PCBs in the BATC shop and advice on the BATC forum. It is also possible to use a standard satellite receiver or BATC Minitiouner to provide the DC supply and split out the signals using a power splitter.
-==Octagon LNB==
+===Octagon LNB===
 The octagon range of PLL LNBs were the first mass market LNBs to use a PLL rather than free running DRO for the Local oscillator.  This made them suitable for receiving narrow band (SSB and CW) signals although they do suffer some temperature drift.  The Farnham Web SDR used an unmodified Octagon LNB as the 10GHz receiver for a couple of years.

← Older revision		Revision as of 14:31, 3 March 2019
Line 2:		Line 2:

	A number of LNBs are suitable for receiving amateur band transmissions and this page lists them.		A number of LNBs are suitable for receiving amateur band transmissions and this page lists them.
		+
		+	===DC Supply===
		+
		+	The basic LNB requires a DC supply fed up the coax. This powers the internals and also selects polarisation. A 12V supply selects Vertical polarisation, an 18V supply Horizontal polarisation. Standard LNBs like the Octagon range have two local oscillator (LO) frequencies, 9.75 GHz and 10.6 GHz. The higher is selected by adding a 22kHz signal to the DC supply. For Es'Hail-2 the lower LO is used and this 22kHz tone is not required. Some newer wideband LNBs intended for SkyQ are different, so beware.
		+
		+	The 12V or 18V LNB supply and returned signals share the same coax. A bias-T https://en.wikipedia.org/wiki/Bias_tee is needed to separate the DC from the IF but this can be very simple. Either buy one or make it using an RF choke and a DC blocking capacitor. There are some designs available elsewhere in this Wiki, PCBs in the BATC shop and advice on the BATC forum. It is also possible to use a standard satellite receiver or BATC Minitiouner to provide the DC supply and split out the signals using a power splitter.
		+

	==Octagon LNB==		==Octagon LNB==

@@ Line 76: / Line 76: @@
 While having a stable LO might be perfect for narrow-band operation, any increase in phase noise might reduce the apparent sensitivity for DATV.  I found that a 1MS DVB-S signal that gave 24 dB MER with the crystal oscillator only gave 21 dB MER with the external reference; this will need more investigation.
-==Goodbay LNB==
+==Goobay LNB==
 To be completed

← Older revision		Revision as of 17:37, 2 February 2019
Line 75:		Line 75:

	While having a stable LO might be perfect for narrow-band operation, any increase in phase noise might reduce the apparent sensitivity for DATV. I found that a 1MS DVB-S signal that gave 24 dB MER with the crystal oscillator only gave 21 dB MER with the external reference; this will need more investigation.		While having a stable LO might be perfect for narrow-band operation, any increase in phase noise might reduce the apparent sensitivity for DATV. I found that a 1MS DVB-S signal that gave 24 dB MER with the crystal oscillator only gave 21 dB MER with the external reference; this will need more investigation.
		+
		+	==Goodbay LNB==
		+
		+	To be completed

← Older revision		Revision as of 17:33, 2 February 2019
Line 12:		Line 12:

	[http://g4jnt.com/OctagonExtLo.pdf G4JNT's Modification for an External LO (for 27 MHz Octagon LNB)]		[http://g4jnt.com/OctagonExtLo.pdf G4JNT's Modification for an External LO (for 27 MHz Octagon LNB)]
−
−	~~[https://f5xg.jimdo.com/antennes/syst%C3%A8me-duo-bande-2-4ghz-10ghz/ F5XG's Dual Band Feed for Es'hail-2]~~

	[http://www.hb9afo.ch/articles/pll-lnb/10ghz_pll-lnb.htm HB9AFO's Modifications for an external LO on an Avenger LNB (in French)]		[http://www.hb9afo.ch/articles/pll-lnb/10ghz_pll-lnb.htm HB9AFO's Modifications for an external LO on an Avenger LNB (in French)]

@@ Line 9: / Line 9: @@
 This drift has caused a lot of people to investigate locking or replacing the internal crystal reference (27 or 25MHz) with an external TCXO or GPS locked source.   Details of how to lock a quad LNB are described lower down on this page and the following is a list of links to pages describing modifications and testing the Octagon units:
-[http://g4jnt.com/PLL_LNB_Tests.pdf G4JNT's Modifications and Measurements]
+[http://g4jnt.com/PLL_LNB_Tests.pdf G4JNT's Modifications and Measurements on a 27MHz PLL Octagon unit]
 [http://g4jnt.com/OctagonExtLo.pdf G4JNT's Modification for an External LO (for 27 MHz Octagon LNB)]

@@ Line 31: / Line 31: @@
 G3YGF posted this on the UKmicrowave group forum:
-''I have measured a few of these.
+''I have measured a few of these. The earlier 27MHz dual version has about 1.2dB NF at 980MHz (bottom of tv satellite band) and at 618MHz (10368MHz), on both polarisations. Later ones are typically 1.5dB at 980MHz on either polarisation, and at 618MHz (10368MHz) about 1.5dB on the probe furthest from the backshort (V >15) and 2dB on the probe nearest the backshort (V <15v).''
 ''The 25MHz dual version is about 1.2dB at 980MHz on either polarisation,

@@ Line 34: / Line 34: @@
 The earlier 27MHz dual version has about 1.2dB NF at 980MHz (bottom of tv satellite band) and at 618MHz (10368MHz), on both polarisations.
 Later ones are typically 1.5dB at 980MHz on either polarisation,
-and at 618MHz (10368MHz) about 1.5dB on the probe furthest from the backshort (V >15) and 2dB on the probe nearest the backshort (V <15v).
+and at 618MHz (10368MHz) about 1.5dB on the probe furthest from the backshort (V >15) and 2dB on the probe nearest the backshort (V <15v).''
-The 25MHz dual version is about 1.2dB at 980MHz on either polarisation,
+''The 25MHz dual version is about 1.2dB at 980MHz on either polarisation,
 and at 618MHz 1.2dB on the probe furthest from the backshort and about 2.9dB on the probe nearest the backshort.
-(Measurements made using sky/ground noise).
+(Measurements made using sky/ground noise).''
-The main difference appears to be that the gain rolls off much more rapidly below the satellite band in the FET preamplifier on the probe nearest the backshort, so changing the IF makes no difference.
+''The main difference appears to be that the gain rolls off much more rapidly below the satellite band in the FET preamplifier on the probe nearest the backshort, so changing the IF makes no difference.
-The figures are approximate - they do vary somewhat between samples...
+The figures are approximate - they do vary somewhat between samples...''
-The measurements are on unmodified LNBs.
+''The measurements are on unmodified LNBs.''
-We use these LNBs on the FRARS EME system.
+''We use these LNBs on the FRARS EME system and attempts to modify the LNB to interface to WG16 or different circular feeds usually lose about 0.3-0.4dB.''
-Attempts to modify the LNB to interface to WG16 or different circular feeds usually lose about 0.3-0.4dB.
+''We are currently trying to work out why... Matching screws do not improve it, so I don't think it is the Lambda-g......''
 ===Locking the Quad Octagon LNB to a 25 MHz Reference===