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Re: What does zero-beat sound like? #ubitx

 

The tuning is close for those that do not have test equipment.

What I usually do is set a sideband rig readout either 1000 hz higher or lower than the desired frequency depending on the sideband .? Then feed it a signal that is on frequency and put a counter on the speaker.? When the speaker output is 1000 hz, then the receiver is set.? No guessing about trying to hear the zero beat below around 100 hz or less.

While I bought used test equipment and do not have that much in it, here I set with a $ 120 rig and use about? $ 5000 worth of test equipment to set it with.
Would have been much less expensive to buy a transceiver already to go..But I would not have nearly as much fun working with this little rig.?

As I see it, Mr. Farhan did an excellent job of making an inexpensive rig for those that can not afford a more expensive rig, and for those of us that like to tinker with items that we do not have the skill or way to make the circuit boards and such from scratch.?
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de ku4pt




On Thu, May 31, 2018 at 5:11 PM, Mike aka KC2WVB <rb5363@...> wrote:
OK, I thought about this can of worms I opened on the ride home. Given the stores are 60 miles from the mountain top home I am staying at this summer I had roughly 45 minutes to sort through the various responses.

First, we should agree that the metric that establishes the accuracy one is aiming for is wave? lenght. Wave length of course is the distance propagated in one complete cycle. So Jerry is correct in that if your aim is to set an oscillator at a set frequency then being off by as much as 300 hz when using? a 30 MHz signal as a reference is equivalent to being off by 10 hz when using a 1 Mhz signal as a? reference. This is due to 10 cycles at 1Mhz and 300 cycles at 30 Mhz, when viewed as occupying distance, are equal in lenght.

If I have bad hearing it is normally at the low or high end of the spectrum and what Jerry pointed out shows that I can still obtain the accuracy of someone with better hearing by using a higher frequency for a reference signal and if our hearing is equivalent then I simply obtain higher accuracy by using the higher frequency reference signal.

As the other gentleman pointed out being able to have accuracy that resolves to perfection is most likely not even possible because of capacitor issues that end up blocking or at least attenuating the lowest of the lows in terms of audio signals.

However, I do disagree with defining theoretical so as to indicate other than actual conditions for while the theoretical and actual may not coincide there are times that they do.

Thank you all for chipping in to this discussion brought on by my thinking out loud. Its been interesting.

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