Questions tagged [vfo]

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2 votes
1 answer
126 views

How to handle old stuck tuning slugs?

My Swan 350 radio has tuning slugs in the VFO to handle different bands. The 10-meter band has a slug that wont come out, I may need to use a longer wrench but these old slugs break apart and crumble. ...
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0 votes
1 answer
56 views

Swan 350 calibration

So my swan 350 needs to sing properly and order it for to do so the VFO needs to be calibrated. I do not have a working frequency counter. How do I get this stuff fixed so I can get her singing right. ...
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2 votes
3 answers
79 views

Explanation of VFO as one part of the the tuning variables in mixers

I do apologize if this has been answer previously, but the term "VFO" seems to have become overloaded over the years. I think I have a handle on the notion of multiple VFOs on device for the ...
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  • 1,212
7 votes
2 answers
347 views

How to reduce VFO sensitivity to the hand capacitance?

I got a little tired of Si5351 and decided to build an analog CW transceiver. It's almost done and works pretty well. However, I discovered one problem. When I reach the VFO control with my hand the ...
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4 votes
3 answers
2k views

What is the difference between RIT and XIT?

What is the difference between RIT and XIT? When would one use one and not the other for split (or other) HF operation? When would one need both? Which one is more useful for a transceiver to have ...
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3 votes
4 answers
1k views

What is the use of dual VFOs?

What is the value of more than one VFO in an HF transceiver? Many novice rigs only have a single crystal oscillator, and a vast number of famous classic transceivers, HF kits, and QRP rigs only have a ...
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  • 12.4k
2 votes
0 answers
49 views

Clocking A and N in a Dual-modulus PLL Prescaler

In an effort to "up my game" attempting to build a VFO for my DIY transceiver, I've been looking at PLL theory and circuits. Many of my research references are quite old and I understand that many of ...
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  • 917
1 vote
2 answers
1k views

How to convert a crystal controlled tranceiver to VFO (aka Unbinding from the Rock)?

If you look at the circuit diagram for a Colpitts crystal oscillator, it's pretty simple -- a crystal, load resistor, and capacitive voltage divider, with the positive supply feeding the control ...
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  • 3,881
6 votes
2 answers
300 views

Does the waveform of the VFO necessarily have to be sinusoidal?

Looking around for a VFO online, I see most kits/manufacturers make it a point to mention the waveform. Sinusoidal is a fundamental shape, whereas others (sawtooth, square) are a composite. I recall ...
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  • 2,744
3 votes
1 answer
504 views

Can an external VFO be injected into a commercial rig?

Constraints of various kinds preclude any investment in a rig at present; so I find myself pondering the means to get back on the band piece-meal. Say I were successful in an attempt to throw ...
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  • 2,744