MiniTiouner Power Level Indication - Revision history

G8GKQ: /* Portsdown Implementation */

2021-12-18T17:24:37Z

Portsdown Implementation

G8GKQ: /* Detailed Analysis */

2021-07-20T09:17:33Z

Detailed Analysis

G8GKQ: /* (Proposed) Portsdown Implementation */

2021-07-19T17:08:05Z

(Proposed) Portsdown Implementation

G8GKQ: /* Input Power Measurement in the FTS-4334 Tuner */

2021-07-19T17:06:19Z

Input Power Measurement in the FTS-4334 Tuner

G8GTZ at 15:19, 19 July 2021

2021-07-19T15:19:28Z

G8GTZ at 15:19, 19 July 2021

2021-07-19T15:19:00Z

G8GKQ: /* Tabulated Results */

2021-07-18T19:14:33Z

Tabulated Results

G8GKQ: /* Tabulated Results */

2021-07-18T19:12:34Z

Tabulated Results

Show changes

G8GKQ: /* Tabulated Results */

2021-07-18T19:00:33Z

Tabulated Results

G8GKQ: /* (Proposed) Portsdown Implementation */

2021-07-18T18:56:43Z

(Proposed) Portsdown Implementation

← Older revision		Revision as of 17:24, 18 December 2021
Line 36:		Line 36:

	The 2 AGC levels are available as output parameters in the LongMynd software. Using a look-up table it is possible to translate this to a dB figure with the same reference of -70 at the point that MiniTiouner reaches its optimum performance. This means that all the user has to remember (if using MiniTioune or Portsdown) is that the quiescent input signal level should be above -70 dB. Portsdown will display sensible values up to -35 dB, which should be adequate range for most applications.		The 2 AGC levels are available as output parameters in the LongMynd software. Using a look-up table it is possible to translate this to a dB figure with the same reference of -70 at the point that MiniTiouner reaches its optimum performance. This means that all the user has to remember (if using MiniTioune or Portsdown) is that the quiescent input signal level should be above -70 dB. Portsdown will display sensible values up to -35 dB, which should be adequate range for most applications.
		+
		+
		+	===Ryde Implementation===
		+
		+	The Ryde on-screen display now also displays this power level indication. The calibration is identical to the Portsdown, but it does not display in a different colour if too low (less than -70 dB).

	===Accuracy Warning===		===Accuracy Warning===

@@ Line 25: / Line 25: @@
 Three areas of operation were observed:
-# At low input levels (below -70 dBm indicated RF Power) the tuner runs at maximum gain, but is unable to use the fuill range of the analogue to digital converter.  This leads to lower MER or failure to decode.
+# At low input levels (below -70 dBm indicated RF Power) the tuner runs at maximum gain, but is unable to use the full range of the analogue to digital converter.  This leads to lower MER or failure to decode.
 # At optimum input levels, the internal AGC loop adjusts the internal gain to provide the optimum amplitude of signal to the analogue to digital converter.  This range, which is indicated at between -70 dBm and -27 dBm on Minitioune, provides the optimum decoding performance.
 # At high input levels (-26 dBm indicated RF Power and above on MiniTioune)  the LNA on the input to the tuner has its gain reduced to maintain reasonable levels into the analogue to digital converter.

@@ Line 33: / Line 33: @@
 To measure the power measurement bandwidth, broadband noise was input to the tuner at 700 MHz and the level adjusted to an indicated RF Power of -65 dB.  A 700 MHz carrier was then added to the noise to increase the indicated level by a real 10 dB (as previously measured in the signal tests above).  The frequency of the 700 MHz carrier was then moved HF and LF to find the offset where the indicated level dropped by a real 3 dB.  This was at + and - 5 MHz, so a 10 MHz 3dB bandwidth is estimated for the power measurement.
-===(Proposed) Portsdown Implementation===
+===Portsdown Implementation===
-The main AGC level is available as an output parameter in the LongMynd software.  Using a look-up table it is possible to translate this to a dB figure with the same reference of -70 at the point that MiniTiouner reaches its optimum performance.  From that point as signal increases the level will be displayed in approxmate 1 dB steps.  This means that all the user has to remember (if using MiniTioune or Portsdown) is that the quiescent input signal level should be above -70 dB.  Portsdown will display sensible values up to -35 dB, which should be adequate range for most applications.
+The 2 AGC levels are available as output parameters in the LongMynd software.  Using a look-up table it is possible to translate this to a dB figure with the same reference of -70 at the point that MiniTiouner reaches its optimum performance.  This means that all the user has to remember (if using MiniTioune or Portsdown) is that the quiescent input signal level should be above -70 dB.  Portsdown will display sensible values up to -35 dB, which should be adequate range for most applications.
 ===Accuracy Warning===

@@ Line 17: / Line 17: @@
 The received signal in the FTS-4334 Tuner is amplified, down-converted to a near-zero IF (using a local oscillator near signal frequency) and then digitised in an analogue to digital converter.  All the demodulation takes place in the digital domain after the analogue to digital converter.  For the best performance, the full range of the analague to digital converter needs to be used, without overflowing.  Weaker signals will still be digitised, but with a lower resolution (which appears as more noise), leading to a lower MER or failure to decode at all.  Signals that overflow will be distorted leading to errors, again affecting MER and decoding performance.
-The tuner has at least 2 AGC loops to adjust the input level and it is thought that it is these that are monitored to display the RF Power in the MiniTiouner software, along with possibly the raw I and Q values from the analogue to digital converter.  The Portsdown is able to monitor  AGC1 and AGC2, but not the RF Preamp gain, which is more than adequate for our needs giving 70 dB of range.
+The tuner has at least 2 AGC loops to adjust the input level and it is thought that it is these that are monitored to display the RF Power in the MiniTiouner software.  The Portsdown is able to monitor AGC1 and AGC2, but not the RF Preamp gain, these 2 AGC values are more than adequate for our needs, giving 70 dB of range.
 ===Detailed Analysis===

← Older revision		Revision as of 15:19, 19 July 2021
Line 1:		Line 1:
−	As with any receiver, the MiniTiouner needs the input signal strength to be within a defined range to achieve best results.	+	As with any receiver, the MiniTiouner USB receiver needs the input signal strength to be within a defined range to achieve best results.

	The Serit 4334 NIM or tuner is designed to be used in a satellite receive system fed by an LNB on the dish with ~55dB of gain To compensate for this, MiniTiouner must always be used with external preamp followed by a satellite line amplifier when used to receive terrestrial signals.		The Serit 4334 NIM or tuner is designed to be used in a satellite receive system fed by an LNB on the dish with ~55dB of gain To compensate for this, MiniTiouner must always be used with external preamp followed by a satellite line amplifier when used to receive terrestrial signals.

@@ Line 1: / Line 1: @@
-As with any receiver, the MiniTiouner needs the input signal strength to be within a defined range to achieve best results.  As the MiniTiouner must always be used with an external preamp or LNB, this means putting the right amount of gain between the aerial and the MiniTiouner input.  I had not found any documentation on the correct input level and wanted to implement some indication on the Portsdown, so did some tests.
+As with any receiver, the MiniTiouner needs the input signal strength to be within a defined range to achieve best results.
 ===Summary of Results===
@@ Line 5: / Line 9: @@
 My conclusions were:
-# For the MiniTiouner to operate at its best and be as sensitive as possible, the RF Power indicated on the MiniTioune software with no incoming signal should be above -70 dBm.  No advantage was observed with higher indicated RF Powers.
+# For the MiniTiouner to operate at its best and be as sensitive as possible, the RF Power indicated on the MiniTioune RF power meter with no incoming signal should be between -70 and -65dBm.  No advantage was observed with higher indicated RF Powers.
 # The indicated RF Power on MiniTioune is useless as a means of peaking weak RB-TV signals for maximum signal strength, as the power is measured across about 10 MHz of bandwidth (3dB) and the noise power in this bandwidth swamps any marginal increase in signal power.
 # It is very difficult to measure the RF Power using a digital tuner and the indications on MiniTioune are neither linear nor absolute (labelling as dBm is misleading).  Having said that, the indication is very useful - thanks to F6DZP!

@@ Line 44: / Line 44: @@
 ! Input Lev (dB) !! MT Indication !! AGC1 !! AGC2 !! Portsdown Indication !! Remarks
 |-
-| -67 || -94 || 0 || 3200 || < -97 || Reduced MER
+| -67 || -94 || 0 || 3200 || -97 || Reduced MER
 |-
-| -66 || -93 || 0 || 2740 || < -96 || Reduced MER
+| -66 || -93 || 0 || 2740 || -96 || Reduced MER
 |-
-| -65 || -92 || 0 || 2560 || < -95 || Reduced MER
+| -65 || -92 || 0 || 2560 || -95 || Reduced MER
 |-
-| -64 || -91 || 0 || 2380 || < -94 || Reduced MER
+| -64 || -91 || 0 || 2380 || -94 || Reduced MER
 |-
-| -63 || -91 || 0 || 2200 || < -93 || Reduced MER
+| -63 || -91 || 0 || 2200 || -93 || Reduced MER
 |-
-| -62 || -90 || 0 || 2020 || < -92 || Reduced MER
+| -62 || -90 || 0 || 2020 || -92 || Reduced MER
 |-
-| -61 || -89 || 0 || 1840 || < -91 || Reduced MER
+| -61 || -89 || 0 || 1840 || -91 || Reduced MER
 |-
-| -60 || -89 || 0 || 1660 || < -90 || Reduced MER
+| -60 || -89 || 0 || 1660 || -90 || Reduced MER
 |-
-| -59 || -88 || 0 || 1480 || < -89 || Reduced MER
+| -59 || -88 || 0 || 1480 || -89 || Reduced MER
 |-
-| -58 || -87 || 0 || 1300 || < -88 || Reduced MER
+| -58 || -87 || 0 || 1300 || -88 || Reduced MER
 |-
-| -57 || -86 || 0 || 1140 || < -87 || Reduced MER
+| -57 || -86 || 0 || 1140 || -87 || Reduced MER
 |-
-| -56 || -85 || 0 || 1000 || < -86 || Reduced MER
+| -56 || -85 || 0 || 1000 || -86 || Reduced MER
 |-
-| -55 || -84 || 0 || 880 || < -85 || Reduced MER
+| -55 || -84 || 0 || 880 || -85 || Reduced MER
 |-
-| -54 || -83 || 0 || 780 || < -84 || Reduced MER
+| -54 || -83 || 0 || 780 || -84 || Reduced MER
 |-
-| -53 || -82 || 0 || 700 || < -83 || Reduced MER
+| -53 || -82 || 0 || 700 || -83 || Reduced MER
 |-
-| -52 || -81 || 0 || 625 || < -82 || Reduced MER
+| -52 || -81 || 0 || 625 || -82 || Reduced MER
 |-
-| -51 || -80 || 0 || 560 || < -81 || Reduced MER
+| -51 || -80 || 0 || 560 || -81 || Reduced MER
 |-
-| -50 || -79 || 0 || 500 || < -80 || Reduced MER
+| -50 || -79 || 0 || 500 || -80 || Reduced MER
 |-
-| -49 || -78 || 0 || 450 || < -79 || Reduced MER
+| -49 || -78 || 0 || 450 || -79 || Reduced MER
 |-
-| -48 || -76 || 0 || 400 || < -78 || Reduced MER
+| -48 || -76 || 0 || 400 || -78 || Reduced MER
 |-
-| -47 || -75 || 0 || 360 || < -77 || Reduced MER
+| -47 || -75 || 0 || 360 || -77 || Reduced MER
 |-
-| -46 || -74 || 0 || 325 || < -76 || Reduced MER
+| -46 || -74 || 0 || 325 || -76 || Reduced MER
 |-
-| -45 || -73 || 0 || 290 || < -75 || Reduced MER
+| -45 || -73 || 0 || 290 || -75 || Reduced MER
 |-
-| -44 || -72 || 0 || 255 || < -74 || Reduced MER
+| -44 || -72 || 0 || 255 || -74 || Reduced MER
 |-
-| -43 || -71 || 0 || 225 || < -73 || Reduced MER
+| -43 || -71 || 0 || 225 || -73 || Reduced MER
 |-
 | -42 || -71 || 0 || 200 || -72 || Reduced MER

@@ Line 42: / Line 42: @@
 {| class="wikitable"
 |-
-! Input Lev (dB) !! MT Indication !! LM AGC1 Val !! Portsdown Indication !! Remarks
+! Input Lev (dB) !! MT Indication !! AGC1 !! AGC2 !! Portsdown Indication !! Remarks
 |-
 | -60 || -89 || 0 || < -70 || Reduced MER
 |-
-| -59 || -88 || 0 || < -70 || Reduced MER
+| -59 || -88 || 0 || 148 || < -70 || Reduced MER
 |-
-| -58 || -87 || 0 || < -70 || Reduced MER
+| -58 || -87 || 0 || 148 || < -70 || Reduced MER
 |-
-| -57 || -86 || 0 || < -70 || Reduced MER
+| -57 || -86 || 0 || 148 || < -70 || Reduced MER
 |-
-| -56 || -85 || 0 || < -70 || Reduced MER
+| -56 || -85 || 0 || 148 || < -70 || Reduced MER
 |-
-| -55 || -84 || 0 || < -70 || Reduced MER
+| -55 || -84 || 0 || 148 || < -70 || Reduced MER
 |-
-| -54 || -83 || 0 || < -70 || Reduced MER
+| -54 || -83 || 0 || 148 || < -70 || Reduced MER
 |-
-| -53 || -82 || 0 || < -70 || Reduced MER
+| -53 || -82 || 0 || 148 || < -70 || Reduced MER
 |-
-| -52 || -81 || 0 || < -70 || Reduced MER
+| -52 || -81 || 0 || 148 || < -70 || Reduced MER
 |-
-| -51 || -80 || 0 || < -70 || Reduced MER
+| -51 || -80 || 0 || 148 || < -70 || Reduced MER
 |-
-| -50 || -79 || 0 || < -70 || Reduced MER
+| -50 || -79 || 0 || 148 || < -70 || Reduced MER
 |-
-| -49 || -78 || 0 || < -70 || Reduced MER
+| -49 || -78 || 0 || 148 || < -70 || Reduced MER
 |-
-| -48 || -76 || 0 || < -70 || Reduced MER
+| -48 || -76 || 0 || 148 || < -70 || Reduced MER
 |-
-| -47 || -75 || 0 || < -70 || Reduced MER
+| -47 || -75 || 0 || 148 || < -70 || Reduced MER
 |-
-| -46 || -74 || 0 || < -70 || Reduced MER
+| -46 || -74 || 0 || 148 || < -70 || Reduced MER
 |-
-| -45 || -73 || 0 || < -70 || Reduced MER
+| -45 || -73 || 0 || 148 || < -70 || Reduced MER
 |-
-| -44 || -72 || 0 || < -70 || Reduced MER
+| -44 || -72 || 0 || 148 || < -70 || Reduced MER
 |-
-| -43 || -71 || 0 || < -70 || Reduced MER
+| -43 || -71 || 0 || 148 || < -70 || Reduced MER
 |-
-| -44 || -71 || 0 || < -70 || Reduced MER
+| -44 || -71 || 0 || 148 || < -70 || Reduced MER
 |-
-| -43 || -71 || 0 || < -70 || Reduced MER
+| -43 || -71 || 0 || 148 || < -70 || Reduced MER
 |-
-| -42 || -71 || 0 || < -70 || Reduced MER
+| -42 || -71 || 0 || 148 || < -70 || Reduced MER
 |-
-| -41 || -71 || 0 || < -70 || Reduced MER
+| -41 || -71 || 0 || 148 || < -70 || Reduced MER
 |-
-| -40 || -71 || 1 || -70 || Best MER
+| -40 || -71 || 1 || 148 || -70 || Best MER
 |-
-| -39 || -71 || 10 || -69 || Best MER
+| -39 || -71 || 10 || 148 || -69 || Best MER
 |-
-| -38 || -70 || 21800 || -68 || Best MER
+| -38 || -70 || 21800 || 148 || -68 || Best MER
 |-
-| -37 || -68 || 25100 || -67 || Best MER
+| -37 || -68 || 25100 || 148 || -67 || Best MER
 |-
 | -36 || -66 || 27100 || -66 || Best MER