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Mod-VFO Drehrichtung_en.docx 

January 28, 2019, © 

Elcon

, Switzerland 

Seite 3 / 7 

Introduction 

 

Normally you are used to turning the VFO knob clockwise increasing the frequency and vice 
versa. With the FT-301D it is just the other way around and therefore very unusual. 

This is due to the frequency conditioning of the FT-301. 

 

Figure 1  

 

As shown in Figure 1, the VFO frequency is subtracted from the crystal frequencies for the 
different bands (Band Crystal). Thus, the VFO frequency runs in opposite direction to the 
premixer frequency and thus also to the transmit frequency (Tx frequency). 

 

 

Figure 2  

 

The variable capacitor of the VFO is designed in such a way that the rotor plates turn out 
clockwise and thus the capacity decreases -> the frequency of the VFO increases -> the Tx 
frequency decreases. 

As shown in Figure 2, the fiber glass spreaders on the two rotor plate packs prevent them 
from being turned counterclockwise beyond the maximum capacity. However, this would be 
absolutely necessary to reverse the frequency to the direction of rotation.  

 

 

Spreader 

Summary of Contents for FT-301D

Page 1: ...nnhaldenstrasse 8 3510 Konolfingen Switzerland Telefon Fax E Mail Shop 41 0 31 792 04 61 41 0 31 792 04 62 info elcon ch http shop elcon ch Modification VFO reversal of rotations Yaesu FT 301D Modific...

Page 2: ...e variable capacitor 4 2 1 Removing the spreaders in the VFO variable capacitor 4 2 2 Mechanical adjustment of the VFO variable capacitor 5 2 3 Functional test 6 3 Changing the direction of rotation o...

Page 3: ...fferent bands Band Crystal Thus the VFO frequency runs in opposite direction to the premixer frequency and thus also to the transmit frequency Tx frequency Figure 2 The variable capacitor of the VFO i...

Page 4: ...Removing the spreaders in the VFO variable capacitor Remove the four screws and the VFO cover Remove very carefully without bending the rotor plate of the variable capacitor VC801 both fiber glass sp...

Page 5: ...unit so that the open variable capacitor is easily accessible from above and the tuning knob at the front Loosen do not unscrew the two grub screws of the gear wheel on the axis of the rotary capacito...

Page 6: ...hear the noise over the entire tuning range without interruption If the noise suddenly decreases at any position of the VFO knob the rotor plates of the variable capacitor are touching the stator In...

Page 7: ...ability Any actions based on the information contained in this document are taken at the user s own responsibility Any liability is excluded both for direct and indirect damages and consequential dama...

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