800 MHz Exciter - Revision history

Bryan at 02:50, 1 December 2016

2016-12-01T02:50:03Z

Bryan: /* Converting VCO */

2016-11-02T17:35:06Z

Converting VCO

Bryan: /* 800 to 900 MHz */

2016-10-29T02:40:17Z

800 to 900 MHz

Bryan: /* Converting VCO */

2016-10-29T02:39:15Z

Converting VCO

Bryan: /* Changing the version bits */

2016-10-27T06:54:40Z

Changing the version bits

Bryan: /* Schematics */

2016-10-27T06:51:19Z

Schematics

Bryan: /* Schematics */

2016-10-27T06:50:45Z

Schematics

Bryan: /* Schematics */

2016-10-27T06:49:36Z

Schematics

Bryan: /* Schematics */

2016-10-27T06:48:55Z

Schematics

Bryan: /* Basics */

2016-10-27T06:47:27Z

Basics

← Older revision		Revision as of 02:50, 1 December 2016
Line 244:		Line 244:

	The 800 MHz Exciter is 00000001 and the 900 MHz exciter needs to be 00000011. This is done by moving R3805 to R3804 to flip that 2nd bit.		The 800 MHz Exciter is 00000001 and the 900 MHz exciter needs to be 00000011. This is done by moving R3805 to R3804 to flip that 2nd bit.
		+
		+	[[Category:Quantar]]

← Older revision		Revision as of 17:35, 2 November 2016
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−	At this point you may wish to hook up the VCO for testing so you can sweep the response at 800 MHz or go right into changing the ~~Communists~~ needed to move it to 900 MHz. If this is your first time, it may be a good idea to understand the response at 800 MHz.	+	At this point you may wish to hook up the VCO for testing so you can sweep the response at 800 MHz or go right into changing the components needed to move it to 900 MHz. If this is your first time, it may be a good idea to understand the response at 800 MHz.

	* To hook up the VCO for testing/tuning without turning the synth chips, temporally remove L3201 and set it aside. Hook up a lead to the pad a shown with 10.2v to power the VCO on it's own.		* To hook up the VCO for testing/tuning without turning the synth chips, temporally remove L3201 and set it aside. Hook up a lead to the pad a shown with 10.2v to power the VCO on it's own.

@@ Line 95: / Line 95: @@
 *First mask of the area with some kapton tape/foil of other heat shield.  The other components will melt if not for this.  A board pre-heater and 610 F at 15 l/m of air flow from a hot air wand will have the shield off in in about 60 seconds.
-<gallery heights=200px widths=200px mode="packed-hover">
+<gallery heights=300px widths=300px mode="packed-hover">
 VCO with shield prep for removal.jpg|800 VCO prepped for desoldering]]
 </gallery>
@@ Line 107: / Line 107: @@
 * To hook up the VCO for testing/tuning without turning the synth chips, temporally remove L3201 and set it aside.  Hook up a lead to the pad a shown with 10.2v to power the VCO on it's own.
-<gallery heights=200px widths=200px mode="packed-hover">
+<gallery heights=300px widths=300px mode="packed-hover">
 Exciter VCO power point.jpg|800 MHz Exciter VCO power point
 </gallery>
@@ Line 115: / Line 115: @@
 * Tack on a wire to the junction of C3200 and R3200 for the steering voltage to be applied.  This will be where 0-9v is injected to tune the VCO.
-<gallery heights=200px widths=200px mode="packed-hover">
+<gallery heights=300px widths=300px mode="packed-hover">
 exciter VCO conversion to 900.jpg|800 exciter VCO conversion to 900
 </gallery>
@@ Line 127: / Line 127: @@
 * Be sure it's smooth on the bottom as you will need to solder it back down to the VCO.  If you remove too much of the resonator the frequency will be too high, but you can always increase the value of C3212 if need be.
-<gallery heights=200px widths=200px mode="packed-hover">
+<gallery heights=300px widths=300px mode="packed-hover">
 Resonator trimmed and shorted.png|800 MHz to 900 MHz exciter resonator
 </gallery>

@@ Line 93: / Line 93: @@
 The VCO is covered by a soldered on shield.  This shield must be removed before we can retune the VCO.
-First mask of the area with some kapton tape/foil of other heat shield.  The other components will melt if not for this.  A board pre-heater and 610 F at 15 l/m of air flow from a hot air wand will have the shield off in in about 60 seconds.
+*First mask of the area with some kapton tape/foil of other heat shield.  The other components will melt if not for this.  A board pre-heater and 610 F at 15 l/m of air flow from a hot air wand will have the shield off in in about 60 seconds.
-[[File:800 VCO with shield prep for removal.jpg|thumb|800 VCO prepped for desoldering]]
+<gallery heights=200px widths=200px mode="packed-hover">
 After about 60-90 seconds the shield should lift right off.  Be careful and pull the shield straight up.  The other parts under the shield will have been reflowed, and the slightest nudge will move them off the board.  Once it's flowed, and while keeping the heat moving on the VCO case, pull the case straight up with some needle nose pliers.  The case should come clean off, though you may need to rock it back and forth a bit.
@@ Line 102: / Line 104: @@
-At this point you may wish to hook up the VCO for testing so you can sweep the response at 800 MHz or go right into changing the companuits needed to move it to 900 MHz.  If this is your first time, it may be a good idea to understand the response at 800 MHz.
+* To hook up the VCO for testing/tuning without turning the synth chips, temporally remove L3201 and set it aside.  Hook up a lead to the pad a shown with 10.2v to power the VCO on it's own.
-To hook up the VCO for testing/tuning without turning the synth chips, temporally remove L3201 and set it aside.  Hook up a lead to the pad a shown with 10.2v to power the VCO on it's own.
+* The next step is to remove the ceramic resonator from the VCO and C3212.  While the board is still warm replace C3212 with a 3.3 or 3 pf 0603 NPO unit.
-[[File:800 Exciter VCO power point.jpg|thumb|800 MHz Exciter VCO power point]]
+* Tack on a wire to the junction of C3200 and R3200 for the steering voltage to be applied.  This will be where 0-9v is injected to tune the VCO.
-The next step is to remove the ceramic resonator from the VCO and C3212.  While the board is still warm replace C3212 with a 3.3 or 3 pf 0603 NPO unit.
+Now we will modify the VCO resonator by using a diamond grinding wheel to shave the shorted end down.  It's possible to do the front end but it will destroy the center conductor lead, and you will need to replace it with a small section of wire.
-Now we will modify the VCO resonator by using a diamond grinding wheel to shave the shorted end down.  It's possible to do the front end but it will destroy the center conductor lead, and you will need to replace it with a small section of wire.
+* Grind the resonator down to 0.320" long not including the lead.
-Grind the resonator down to 0.320" long not including the lead.
+* Now use a small piece of copper foil and solder it on the end to the outer conductor of the resonator over the end that was ground down.  Solder the inner conductor to the copper foil as well.  This should make a nice flat short on the end of the resonator.
-Now use a small piece of copper foil and solder it on the end to the outer conductor of the resonator.  Using a small iron solder it to the center conductor of the resonator.  Be sure it's smooth on the bottom as you will need to solder it back down to the VCO.  If you remove too much of the resonator the frequency will be too high, but you can always increase the value of C3212 if need be.
+* Be sure it's smooth on the bottom as you will need to solder it back down to the VCO.  If you remove too much of the resonator the frequency will be too high, but you can always increase the value of C3212 if need be.
-[[File:Resonator trimmed and shorted.png|thumb|800 MHz to 900 MHz exciter resonator]]
+<gallery heights=200px widths=200px mode="packed-hover">
 The VCO shield will make the VCO frequency go up by about 2 MHz when in place as well.  Keep this in mind for tuning the VCO; it's best to be 5-6 MHz low with the shield off and then correct it up with a grinder on the tuning capacitor.
-Here is my notes on the tuning range of the VCO at various modification points.  Note this is with the shield off.  As you can see in the highlighted row, with the shield on it will cover up to 941 MHz at the upper end.  This is ideal for ham band coverage.
+Here are my notes on the tuning range of the VCO at various modification points.  '''Note this is with the shield off.'''  As you can see in the highlighted row, with the shield on it will cover up to 941 MHz at the upper end.  This is ideal for ham band coverage.
 This table shows my notes on resonate frequency of the VCO vs. part changes and trimming the resonator.

@@ Line 218: / Line 218: @@
 |-
 | XXXXXXXn || R3802 || R3803
-|-
+|- style="background:Pink"
 | XXXXXXnX || R3804 || R3805
 |-

@@ Line 45: / Line 45: @@
 [[media:800 MHz Exciter TLF6920G diagram.pdf|PDF Excerpt 800 MHz Exciter TLF6920G diagram]]
-<gallery heights=201px widths=201px mode=packed-hover>
+<gallery heights=100px widths=100px mode=packed-hover>
 MHz Exciter TLF6920G-1.png|800 MHz Exciter Diagram 1
 MHz Exciter TLF6920G-2.png|800 MHz Exciter Diagram 2

@@ Line 45: / Line 45: @@
 [[media:800 MHz Exciter TLF6920G diagram.pdf|PDF Excerpt 800 MHz Exciter TLF6920G diagram]]
-<gallery heights=200px widths=200px mode=packed>
+<gallery heights=200px widths=200px mode=packed-hover>
-MHz Exciter TLF6920G-1.png| 800 MHz Exciter Diagram 1
+MHz Exciter TLF6920G-1.png|800 MHz Exciter Diagram 1
-MHz Exciter TLF6920G-2.png| 800 MHz Exciter Diagram 2
+MHz Exciter TLF6920G-2.png|800 MHz Exciter Diagram 2
-MHz Exciter TLF6920G-3.png| 800 MHz Exciter Diagram 3
+MHz Exciter TLF6920G-3.png|800 MHz Exciter Diagram 3
-MHz Exciter TLF6920G-4.png| 800 MHz Exciter Diagram 4
+MHz Exciter TLF6920G-4.png|800 MHz Exciter Diagram 4
 </gallery>

@@ Line 39: / Line 39: @@
 The Exciter controls the PA and will shut down if the PA is not present or detects an error.  The band resistors on the Exciter and PA must match, even if they are programed in the software "codeplug" to different values.
 The service manual excerpt is in PDF and below.
+<gallery heights="200px" widths="200px" mode="packed">
-PDF LINK
+MHz Exciter TLF6920G-1.png| 800 MHz Exciter Diagram 1
+MHz Exciter TLF6920G-2.png| 800 MHz Exciter Diagram 2
-In PNG format.
+MHz Exciter TLF6920G-3.png| 800 MHz Exciter Diagram 3
+MHz Exciter TLF6920G-4.png| 800 MHz Exciter Diagram 4
+</gallery>
 == Conversions ==