[Antennas] homebrew tuner accessory

2003年2月21日 23:00:39 -0800

Have you tired a vibrator off an old electric razor, or maybe an old door 
buzzer, or old electric fence.
But you might pollute the neighbourhood
Chris opr VE7HCB
At 07:53 PM 2003年02月21日 +0000, Durwydd MacTara wrote:
> Broadband "hash" generator
>I want to build one that will create noise at least through 30 MHz with no 
>more than a few mw of power output. I want to use as few components as 
>possible because I want to mount it inside my antenna tuner cabinet, 
>leaving it on all time; the idea being to adjust the tuner for a null in 
>the increased noise floor on the "guess meter" of my receiver, thereby 
>tuning my antenna with no qrm caused by me! I see a minor problem in 
>coupling the noise to the reieever without coupling excessive RF back into 
>the generator when I put my 100 watt transceiver into transmit! this 
>possibly could be solved with a relay. I initally plan to power this 
>circuit from the power to the meter lamps for the tuner. the other 
>possible power source is a +12V receive line from my Kenwood TS-830 
>however I would rather not.
>>My first thought is a couple of ttl nand gates wired as inverters and 
>daisy chained in a loop. As I recall this configuration will oscillate at 
>about 10 KHz with a "nasty" square wave, loaded with harmonics.
>>A second idea is to use a zener diode as a broadband noise generator and 
>feed the noise to a couple of 2M2222 transistors for amps.
>>PLEASE folks, I am open to any and all ideas?
> "Communications" is a People skill, the rest is technology.
> Durwydd MacTara
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