ANICETUS - Revision history

OZ1HFT: +links

2018-12-09T07:21:39Z

+links

OZ1HFT: spelling

2018-12-09T07:13:00Z

spelling

OZ1HFT: +link

2018-12-09T07:11:28Z

+link

OZ1HFT: linkupdate

2016-08-27T12:15:16Z

linkupdate

OZ1HFT: wiki

2016-08-27T12:12:55Z

wiki

OZ1HFT: catchg

2010-01-25T21:53:31Z

catchg

OZ1HFT: +cat

2010-01-25T18:13:07Z

+cat

VK2NRA: /* ANICETUS (Anie) - Preselector - a few designs for narrow band preselectors */ link back to Alex

2009-06-08T00:28:40Z

‎ANICETUS (Anie) - Preselector - a few designs for narrow band preselectors: link back to Alex

VK6APH: /* ANICETUS (Anie) - Preselector - a few designs for narrow band preselectors */

2009-03-29T11:54:44Z

‎ANICETUS (Anie) - Preselector - a few designs for narrow band preselectors

VK6APH: /* ANICETUS (Anie) - Preselector - a few designs for narrow band preselectors */

2009-03-29T11:54:17Z

‎ANICETUS (Anie) - Preselector - a few designs for narrow band preselectors

@@ Line 133: / Line 133: @@
 '''Why Anicetus (Anie)?'''
-Alexiares and his twin brother Anicetus - were the Greek Gods of Defense, in particular the defense of fortified towns and citadels.
+[https://en.wikipedia.org/wiki/Alexiares_and_Anicetus Alexiares] and his twin brother [https://en.wikipedia.org/wiki/Alexiares_and_Anicetus Anicetus] - were the Greek Gods of Defense, in particular the defense of fortified towns and citadels.
-Both were sons of Hercules (Herakles), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.
+Both were sons of [https://en.wikipedia.org/wiki/Hercules Hercules] ([https://en.wikipedia.org/wiki/Heracles Herakles]), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.
 [[Category:Future hardware]]

@@ Line 69: / Line 69: @@
 Similarly, the input and output transformers must be carfully selected so as not to degrade the overall performance.
-I should add that measuring IP3 at his level is not straight forward and I needed to build special test equipment in order to do these tests.
+I should add that measuring IP3 at this level is not straight forward and I needed to build special test equipment in order to do these tests.
 It looks like others have found the same issue; this is a photo of the preselector used in the very high performance Hilberling PT-8000 receiver.

@@ Line 65: / Line 65: @@
 Tuning is obviously manual, you need to select the correct inductor  value and adjust the capacitor each time you change frequency.
-From a practical perspective we need to use a physically large toroidal core to wind the inductor on.  In practice I’ve found that even using a  T300A-2 core there is a slight degradation of IP3 at the +50dBm mark when used with Mercury.
+From a practical perspective we need to use a physically large toroidal core to wind the inductor on.  In practice I’ve found that even using a  T300A-2 core there is a slight degradation of IP3 at the +50dBm mark when used with [[Mercury]].
 Similarly, the input and output transformers must be carfully selected so as not to degrade the overall performance.

@@ Line 91: / Line 91: @@
 There are a number of commercial preselectors that are based on the above principles. These include:
 * https://web.archive.org/web/20100126034937/http://www.m0wwa.co.uk/page/scrpreselector.html
-* http://www.m0wwa.co.uk/PDF/M0WWA_SCR_Preselector.pdf
+* https://herostechnology.co.uk/pdf/M0WWA_SCR_Preselector.pdf
 * https://web.archive.org/web/20101020042250/http://www.m0wwa.co.uk/page/M0WWA_projects.html

@@ Line 1: / Line 1: @@
 === [[ANICETUS]]  (Anie) - Preselector - a few designs for narrow band preselectors ===
 Ideas, comments and suggestions are welcome.
 's Phil...VK6APH
 Whist the jury is still out as to whether most users need some form of filtering before receivers that do Digital Down Conversion there will be situations where strong signals will overload the ADC.
@@ Line 18: / Line 16: @@
 [[Image:Preselector.JPG]]
 At resonance   [f = 1/(2piLC)]  the circuit will have a bandwidth determined by the overall Q of the circuit.  Considering the inductor alone, if we assume a Q of 200 as being practical then we get bandwidths of  (BW = f/Q) of
@@ Line 39: / Line 35: @@
 [[Image:Preselector1.JPG]]
 OK  - so now we place our tuned circuit between the antenna socket and the input of the receiver.  For modeling purposes we can assume an 50 ohm antenna and receiver input impedance.
@@ Line 46: / Line 41: @@
 [[Image:Preselector2.JPG]]
 And the frequency response thus:
 [[Image:Preselector2resp.JPG]]
 Something does not look right here – our 3dB bandwidth is about 14MHz, not 70kHz?
@@ Line 61: / Line 54: @@
 [[Image:Preselector3resp.JPG]]
 The 3dB bandwidth is now 1.4MHz - much more useful.
@@ Line 80: / Line 72: @@
 It looks like others have found the same issue; this is a photo of the preselector used in the very high performance Hilberling PT-8000 receiver.
 [[Image:Hilberling.jpg]]
 They have an interesting way of selecting the taps on the inductor by placing the relays inside the core.
@@ Line 92: / Line 82: @@
 [[Image:HA5RXZ.jpg]]
 In order to tune the preselector to the receiver frequency Peter uses a STAMP uP to measure the receiver local oscillator frequency and select the required relays.  Not shown in the above diagram are the driver circuits for relays 7 to 14 that control the selection of the series capacitance via a binary sequence.
-Initally programming the correct combination of relays will be an intersting software issue.
+Initally programming the correct combination of relays will be an interesting software issue.
 For use with HPSDR we could use an I2C or SPI connected relay driver chip to control the relays. By using Penelope to generate a test signal the system could step across the HF bands and automatically learn which relays to operate on any particular frequency. In this respect the system would be self calibrating.
 There are a number of commercial preselectors that are based on the above principles. These include:
+* https://web.archive.org/web/20100126034937/http://www.m0wwa.co.uk/page/scrpreselector.html
-    http://www.m0wwa.co.uk/page/scrpreselector.html
+* http://www.m0wwa.co.uk/PDF/M0WWA_SCR_Preselector.pdf
-    http://www.m0wwa.co.uk/PDF/M0WWA_SCR_Preselector.pdf
+* https://web.archive.org/web/20101020042250/http://www.m0wwa.co.uk/page/M0WWA_projects.html
-    http://www.m0wwa.co.uk/page/projects.html
 Here is another idea by YU1LM
+* http://www.qsl.net/yu1lm/BP%20FILTER%20HF-YU1LM.pdf
-    http://www.qsl.net/yu1lm/BP%20FILTER%20HF-YU1LM.pdf
-−
 '''Feedback'''
@@ Line 145: / Line 130: @@
 [[Image:Two-transformer.JPG]]
 '''Why Anicetus (Anie)?'''
 Alexiares and his twin brother Anicetus - were the Greek Gods of Defense, in particular the defense of fortified towns and citadels.
 Both were sons of Hercules (Herakles), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.
 [[Category:Future hardware]]

← Older revision		Revision as of 21:53, 25 January 2010
Line 155:		Line 155:
	Both were sons of Hercules (Herakles), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.		Both were sons of Hercules (Herakles), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.

−	[[Category:~~Developer resources~~]]	+	[[Category:Future hardware]]

← Older revision		Revision as of 18:13, 25 January 2010
Line 154:		Line 154:

	Both were sons of Hercules (Herakles), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.		Both were sons of Hercules (Herakles), born after the Hercules' ascension to Olympus and his marriage to the goddess Hebe. Alexiares and Anicetus helped serve as the gatekeepers of Olympus, assisting their father in a role which was commonly assigned to him.
		+
		+	[[Category:Developer resources]]

@@ Line 9: / Line 9: @@
 Whist the jury is still out as to whether most users need some form of filtering before receivers that do Digital Down Conversion there will be situations where strong signals will overload the ADC.
-Some of these situations will be rectified by using a simple High Pass or Low Pass filter before the ADC. The HPSDR Alex project was developed for this purpose.
+Some of these situations will be rectified by using a simple High Pass or Low Pass filter before the ADC. The HPSDR [[ALEXIARES|Alex]] project was developed for this purpose.
 For some users overload from local Medium Wave broadcast stations can be  resolved with the addition of a simple HPF before the receiver.

@@ Line 138: / Line 138: @@
 '''Suggestion from Graham, KE9H '''
-'' Use two switched 4:1 transformers at the input and output. I was thinking of 4:1 at the low end of the band, to widen out the bandwidth at 160 and 80 Meters, so the panadaptor is still useful, and switching to 16:1 for 40 Meters
+'' Use two switched 4:1 transformers at the input and output. I was thinking of 4:1 at the low end of the band, to widen out the bandwidth at 160 and 80 Meters, so the panadaptor is still useful, and switching to 16:1 for 40 Meters and upwards for maximum selectivity. ''
 and upwards for maximum selectivity. ''
 '' Implementation would be two 2:1 (voltage) transformers in series, that were relay switched so that they could be selected for driving the series resonant circuit at either 12.5 Ohms or 3.125 Ohms.''

@@ Line 136: / Line 136: @@
 ''Just a final point. Spare a thought for the humble attenuator. For transmit you need as efficient an antenna as possible but for receive it only needs to bring in enough signal to bring the external noise (atmospheric, man-made, galactic etc.) to just above the receiver's noise floor. Much more than this will exacerbate intermodulation problems.''
-''Suggestion from Graham, KE9H ""
+'''Suggestion from Graham, KE9H '''
 '' Use two switched 4:1 transformers at the input and output. I was thinking of 4:1 at the low end of the band, to widen out the bandwidth at 160 and 80 Meters, so the panadaptor is still useful, and switching to 16:1 for 40 Meters