NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/sci/electron/22161

Internet Message Format | 1993-01-07 | 1.6 KB

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From: [e-mail] (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: RF noise generator circuit wanted
Date: 7 Jan 1993 08:04:24 GMT
Organization: University of Washington, Seattle
Lines: 27
Message-ID: <[e-mail]>
References: <[e-mail]>
NNTP-Posting-Host: carson.u.washington.edu

In article <[e-mail]> [e-mail] (Dave Chu) writes:
>
>I'm looking for a simple circuit that will generate RF noise from
>25-75Mhz.  I was thinking of using a series of 2N222's as class C amps,
>and tune each of the amp at 10 or 15Mhz apart to cover the 25-75Mhz
>range.  I am planning to use this circuit to jam RC or any types of
>remote controlled cars.

    Firstly, jamming is illegal.  Don't get caught.

    Secondly, you want to overwhelm a transmitter that has perhaps
100 mW of output power, all in a narrow band (10 kHz or so); to do
so for the whole 50 MHz you describe, all at once, will require
about 500W of transmitter... doing this with 2N2222's is gonna
be lots of not much fun.

    Doing it for one frequency band at a time, IS practical; check
out _The ARRL Handbook for the Radio Amateur_, any of its dozens
of editions, for grid dip meter plans.  A grid dip meter is a
unmodulated test oscillator, which will easily do the kind of
task you describe.

    And, by reading out the calibrated scale, you can
know roughly what the RC signal frequency is... it's a
genuine, legitimate reason to have the gizmo.  In case
anyone asks.