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Title: N3ZI DDS/ VFO opinions please Post by: Detroit47 on April 05, 2009, 04:29:17 PM I was wondering if one of these units would work with a Globe 500b. Would I have to use direct output from the VFO and go straight to the driver, or could I use it like the original one and go through the frequency multiplier stages. I know that the digital VFO has no harmonics coming out of it. Are the frequency multiplier stages dependent on harmonics from the source oscillator or will they generate them. This is the web site http://www.pongrance.com/ Does anyone know of any other good inexpensive VFO's out there?
73 N8QPC Title: Re: N3ZI DDS/ VFO opinions please Post by: w3jn on April 05, 2009, 05:28:05 PM Not true about the DDS not having harmonics.
In any event it's a moot point as the harmonics are generated in the multiplier stages of the transmitter. I can't vouch for that particular kit but I have built a couple of his digital dials and the quality of the boards is first class. Nice guy, too. Not sure about how great the phase noise and spurs are with this kit. Generally you can improve a DDS by using a better, low noise reference. They still don't come anywhere close to a crystal or good L/C VFO though. And remember phase noise increases as the fundamental is multiplied. Since the 500B puts out a pretty hefty signal, you may get complaints about spurs or some wideband noise on your signal. Then again maybe not. Title: Re: N3ZI DDS/ VFO opinions please Post by: Jim, W5JO on April 05, 2009, 05:34:08 PM If you are interested I have a tuning unit/multiplier unit out of a T 368 that I don't plan to use. I have the 6000 final tube for it. Should you use it, you could feed the 6146 driver directly. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
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