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XV432 Elecraft transverter modification

The original ELECRAFT XV432 transverter is from the techical view not a good product.


Two main problems exists:
1. In the original version the X-tal oscilator stability is bad with big temperature drift +-3kHz!
2. The originaly used PA modul Toshiba S-AU83L is designed for FM modulation, not for SSB.
SSB signal from XV432 is distorted, badly readable.

 

Ad 1:
The original used crystal 134.667MHz should be replaced with the new high accuracy crystal + option, delivered by Elecraft.
The Crystal Oven, delivered by Elecraft, should be used, too.

The original oscilator circuit diagram is a very old design with bad oscilator spectral purity. The XV432 with this oscilator generates large spectrum of not desired products and the frequency is unstable.

This was a reason that I totaly changed the oscilator diagram, using the modern J310 J-FET.
After this change the XV432 is stable with perfect spectral purity.
 

Ad 2:
The original S-AU83L FM module, delivered by Elecraft, should be replaced by a linear PA module. With the original S-AU83L the SSB signal is totaly distorted.

I changed this FM module with a linear Mitsubishi module RA13H4047M (400-470MHz, 13Watt, 12.5V) with the same PIN connection. This new module works fine, the output SSB signal is pure and linear. After this change I can drive the solide state PA (about 8W of drive power), the PA deliver over 350W outup at 432MHz. The signal is perfect and the SSB modulation is fine.
 

 

 

J-FET J310 should by used only. Similar FETs (BF245, 246, 247 etc. works NOT)