UHF Receiver - Revision history

Bryan: /* R1 to R2 */

2024-05-06T03:51:40Z

R1 to R2

Bryan at 03:45, 6 May 2024

2024-05-06T03:45:35Z

Bryan: /* R3 to R2 */

2024-05-06T03:44:27Z

R3 to R2

Bryan at 03:38, 6 May 2024

2024-05-06T03:38:55Z

Bryan: /* Useful Docs */

2024-05-06T03:37:21Z

Useful Docs

Bryan: /* Useful Docs */

2024-05-06T03:35:05Z

Useful Docs

Bryan: /* R1 to R2 */

2024-05-06T03:34:46Z

R1 to R2

Bryan: /* test and verify */

2024-05-06T03:31:10Z

test and verify

Bryan: /* Clean board */

2024-05-06T03:28:30Z

Clean board

Bryan: /* Modify the image filters */

2024-05-06T03:24:55Z

Modify the image filters

@@ Line 103: / Line 103: @@
 * Silicone rubber stock cut to support the underside of the VCO.
 * Flux, and other small parts for rework
-* Quantar backplane extender cables (PCI extender cables cut down to fit)
+* Quantar [[Quantar Backplane Extender|backplane extender cables]] (PCI extender cables cut down to fit)
 * '''A clear understanding of how the VCO's work and how the PLL operates'''
 * Quantar programmed up with the [[Quantar Test Codeplugs|test code plug]].

← Older revision		Revision as of 03:45, 6 May 2024
Line 1:		Line 1:
−	This page covers the Range 1 to Range 4 receivers. The Range 0 is a newer (and easier to modify) design.	+	This page covers the Range 1 to Range 4 receivers. The [[UHF R0 Receiver\|Range 0]] is a newer (and easier to modify) design.

	= Basics =		= Basics =

@@ Line 599: / Line 599: @@
 == R3 to R2 ==
-This works in theory, VCO modification was different.  Not as wide a tuning range, but appears to work.
 == R4 to R2 ==

@@ Line 390: / Line 390: @@
 Now flip the board back and let it pre-heat.  A bit of insulation over the VCO will help for this.  I set my pre-heater to 550f and let it rip for 5-10 min.
-[[File:Vco insulation.jpg|thumb|center|500px|VCO insulation while preheating]]
+[[File:Vco insulation.jpg|thumb|left|500px|VCO insulation while preheating]]
 Set the hot air gun to 550F and 20 L/min of flow, slowly work the shield up in temp and test the solder melting around it.  Once it's completely reflowed, lift up on the center of the shield and pull it directly up and clear of the PCB.  Set it aside to cool.   Careful you don't disturb any of the VCO parts, as they will most likely be reflowed. If you do, don't panic, just look at the before picture and put everything back to how it was on the VCO. It's a pretty easy circuit to figure out.
@@ Line 421: / Line 422: @@
 Set on channel 7 and solder the copper foil short over the lower VCO U bend in such a way that it shows 7.5v on the steering line.  The VCO may unlock when hot, so solder it and then let it cool slightly to lock again.  Blowing on it may help to lock back up.  In practice it's better to have it slightly high as the stub can be ground with diamond grinder tool to shift the voltage down after it's assembled.  Once you have the hang of it soldering it actually not hard.
-[[File:UHF R1 RX VCO Conversion.png|thump|center|500px|VCO modification rules]]
+[[File:UHF R1 RX VCO Conversion.png|thump|left|500px|VCO modification rules]]
 Now to the upper VCO, and here we set to channel 9, and want 4.5v while hot.  This may require bit more cooling to get it to lock between iterations, but it will lock easily.
@@ Line 429: / Line 431: @@
 To reattach the shield, place the shield on the VCO and add a liberal amount of flux around it.  Using the hot air gun to 550F and 20 L/min of flow reflow it and allow it to seat on the VCO.  You may need to add some extra solder around the VCO shield, but typically there's more than enough to make it work.  Once it's totally reflowed allow it to cool and solidify.  As you need to solder the under side of the board, you can do that from the top, or flip it over and solder it.
-[[File:VCO Shield Back on.jpg|thumb|center|500px|VCO Shield Back on]]
+[[File:VCO Shield Back on.jpg|thumb|left|500px|VCO Shield Back on]]
 Allow it all to cool using the insulator over the VCO again.
@@ Line 463: / Line 466: @@
-[[File:UHF R1 to R2 RX Image filter case off R1 to R2.png|thumb|500px|center|UHF R1 to R2 RX Image filter case off R1 to R2]]
+[[File:UHF R1 to R2 RX Image filter case off R1 to R2.png|thumb|500px|left|UHF R1 to R2 RX Image filter case off R1 to R2]]
 Once this is done, re-solder the shield in place.
@@ Line 496: / Line 500: @@
 |}
-[[File:UHF R1 to R2 RX First Mixer board.png|thumb|500px|center|UHF R1 to R2 RX First Mixer board]]
+[[File:UHF R1 to R2 RX First Mixer board.png|thumb|500px|left|UHF R1 to R2 RX First Mixer board]]
 === Change the Module ID ===
@@ Line 502: / Line 507: @@
 Change R2450 to a 3300 Ohm resistor.  This will make the module be seen as an UHF R2 module by the SCM.
-[[File:UHF RX R2450 location.jpg|thumb|500px|center|R2450 location by synthesizer IC]]
+[[File:UHF RX R2450 location.jpg|thumb|500px|left|R2450 location by synthesizer IC]]
 === Clean board ===
@@ Line 590: / Line 596: @@
 [[File:UHF R1 to R2 all boards.png|600px|left|thumb|UHF R1 to R2 all boards]]
-<div style="overflow: hidden">…</div>
+<br clear=all>
 == R3 to R2 ==

← Older revision		Revision as of 03:37, 6 May 2024
Line 590:		Line 590:

	[[File:UHF R1 to R2 all boards.png\|600px\|left\|thumb\|UHF R1 to R2 all boards]]		[[File:UHF R1 to R2 all boards.png\|600px\|left\|thumb\|UHF R1 to R2 all boards]]
		+	<div style="overflow: hidden">…</div>

	== R3 to R2 ==		== R3 to R2 ==

@@ Line 589: / Line 589: @@
 The following image has all the R1 to R2 mods on it and can be printed on a 8.5"x11" or A4 page to have a reference on the desk while doing this modification.
-[[File:UHF R1 to R2 all boards.png|600px|center|thumb|UHF R1 to R2 all boards]]
+[[File:UHF R1 to R2 all boards.png|600px|left|thumb|UHF R1 to R2 all boards]]
 == R3 to R2 ==

← Older revision		Revision as of 03:34, 6 May 2024
Line 513:		Line 513:

	Using the same method as before, note the final VCO voltage at each test frequency and the sensitivity. You should ideally see the same or within 1dB of performance depending on the stability of your test setup. Having the speaker connected helps as you'll be able to hear where it's at. The DSP does noise reduction, and with a steady weak signal, this can make it hard to test SINAD.		Using the same method as before, note the final VCO voltage at each test frequency and the sensitivity. You should ideally see the same or within 1dB of performance depending on the stability of your test setup. Having the speaker connected helps as you'll be able to hear where it's at. The DSP does noise reduction, and with a steady weak signal, this can make it hard to test SINAD.
		+
		+	=== Useful Docs ===
		+
		+	Here is a complete list of the parts which are changed, color coded by section of the board.
		+
		+	{\| class="wikitable" style="vertical-align:bottom;"
		+	\|-
		+	! Part number
		+	! R1
		+	! R2
		+	! Notes
		+	\|- style="background-color:#F4CCCC;"
		+	\| C2050
		+	\| 9.1 pF
		+	\| 8.2 pf +-0.1pf
		+	\| 5% is .41pf
		+	\|- style="background-color:#F4CCCC;"
		+	\| C2051
		+	\| 16pF
		+	\| 13pf +-2pf
		+	\| 5% is .65 pf
		+	\|- style="background-color:#F4CCCC;"
		+	\| C2053
		+	\| 18 pF
		+	\| 16 pf +-2pf
		+	\| 5% is .8 pf
		+	\|- style="background-color:#F4CCCC;"
		+	\| C2054
		+	\| 8.2 pF
		+	\| 6.8 pf +-0.1 pf
		+	\| 5% is .34 pf
		+	\|- style="background-color:#CFE2F3;"
		+	\| C2057
		+	\| 18 pF
		+	\| 16 pf +- 2pf
		+	\| 5% is .8 pf
		+	\|- style="background-color:#CFE2F3;"
		+	\| C2059
		+	\| 18 pF
		+	\| 13 pf +- 2pf
		+	\| 5% is .65 pf
		+	\|- style="background-color:#CFE2F3;"
		+	\| C2070
		+	\| 5.6 pF
		+	\| 3.3 pF +- 0.1 pf
		+	\| 5% is .165pf
		+	\|- style="background-color:#CFE2F3;"
		+	\| C2076
		+	\| 7.54 pF
		+	\| 5.6 pf +- 0.25pf
		+	\| 5% is .28 pf
		+	\|- style="background-color:#CFE2F3;"
		+	\| C2079
		+	\| 9.1 pF
		+	\| 5.6 pf +- 0.25pf
		+	\| 5% is .28 pf
		+	\|- style="background-color:#CFE2F3;"
		+	\| C2083
		+	\| 47 pF
		+	\| 22 pf 5%
		+	\|
		+	\|- style="background-color:#D0E0E3;"
		+	\| R2449
		+	\| 0 Ohm
		+	\| 0 Ohm
		+	\| ID Leave
		+	\|- style="background-color:#D0E0E3;"
		+	\| R2450
		+	\| 0 Ohm
		+	\| 3300 Ohm
		+	\| ID Replace
		+	\|}
		+
		+
		+	The following image has all the R1 to R2 mods on it and can be printed on a 8.5"x11" or A4 page to have a reference on the desk while doing this modification.
		+
		+	[[File:UHF R1 to R2 all boards.png\|600px\|center\|thumb\|UHF R1 to R2 all boards]]

	== R3 to R2 ==		== R3 to R2 ==

@@ Line 510: / Line 510: @@
 Let it cool and move on to testing.
-=== test and verify ===
+=== Test and Verify ===
 == R3 to R2 ==

← Older revision		Revision as of 03:28, 6 May 2024
Line 506:		Line 506:
	=== Clean board ===		=== Clean board ===

		+	I typically wash the board in some solvent/IPA or non-chlorinated brake cleaner and spray out the VCO. An acid brush or toothbrush might be needed to clean it up. After some rinses with clean solvent, bake it at 150f for 30 min and check that's it's clean.
		+
		+	Let it cool and move on to testing.

	=== test and verify ===		=== test and verify ===

← Older revision		Revision as of 03:24, 6 May 2024
Line 497:		Line 497:

	[[File:UHF R1 to R2 RX First Mixer board.png\|thumb\|500px\|center\|UHF R1 to R2 RX First Mixer board]]		[[File:UHF R1 to R2 RX First Mixer board.png\|thumb\|500px\|center\|UHF R1 to R2 RX First Mixer board]]
		+
		+	=== Change the Module ID ===
		+
		+	Change R2450 to a 3300 Ohm resistor. This will make the module be seen as an UHF R2 module by the SCM.
		+
		+	[[File:UHF RX R2450 location.jpg\|thumb\|500px\|center\|R2450 location by synthesizer IC]]

	=== Clean board ===		=== Clean board ===