Re: Varactor VFO???

---------

From: Jeffrey Yuan (yuan@phoenix.Princeton.EDU)
Date: Fri Dec 03 1993 - 11:06:15 EST


In message <9312030729.AA23467@Early-Bird.Think.COM> Mark Shelhamer writes:
>
> For you more experienced homebrewers - can anyone tell me why varactor
> diodes are not more widely used in QRP VFOs? It seems to me that their
> much smaller size and mechanical stability, compared to air variable
> caps, would make then ideal for QRP gear, especially backpackable gear.
>
> There must be some deep dark secret about these that I don't know.
> Or is it just a small capacitance range?
>
> 73
> Mark WA3YNO
>

I believe the reason is that varactor diodes exhibit more drift due to
temperature shifts than variable capacitors. Varactors are used
in the VCO of many phase locked loop frequency synthesizers. Caveat emptor, all
this rambling is from reading the literature not from practical experience :).
Others on this mailing list may have a more satisfactory answer.

73

Jeff N2NXC

(Armchair Homebrewer)

**************************************************************************
* Jeffrey Yuan *
* Department of Molecular Biology *
* Lewis Thomas Laboratory *
* Princeton University *
* Washington Road Phone: 609-258-5939 *
* Princeton, NJ 08544 email: yuan@phoenix.princeton.edu *
* jyuan@molybio.princeton.edu *
**************************************************************************


Search QRP-L Archives

[ QRP-L Archive | ]
[ 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 ]

---------

This archive was generated by hypermail 2b29 on Fri Jun 02 2000 - 11:26:21 EDT

kd4ab@kd4ab.org