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Author Topic: Crystal Calibrator - usage  (Read 1163 times)
KC9QQM
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Posts: 181




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« on: October 12, 2011, 08:18:01 AM »

Ok, this should be easy but...

Have an FT-101e and the manual is a bit confusing as to how to use the built in 25/100khz calibrator to set the frequency ring on the tuning dial.

Do you;
1. Peak the S meter and that is your frequency setting?
2. Zero beat it before the tone starts?
3. Zero beat it after you tuned past the tone.

I have had a few QSO's come back and say I was off their frequency, but I am receiving them just fine as far as quality and how I think their voice should sound. NOTE - I do not have the clarifier on.

Thanks,

Jeff
KC9QQM
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WB6BYU
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« Reply #1 on: October 12, 2011, 08:36:22 AM »

There should only be one frequency where the tone is zero beat - you should get the same
setting tuning from either direction.  That is the proper setting.
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KC9QQM
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Posts: 181




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« Reply #2 on: October 12, 2011, 08:44:11 AM »

Well that is the way I would have thought but when I turn on the calibrator and tune from lower than say the 100khz point to after it, I start to here the tone that is generated from the difference in the tuned frequency and the calibrator, from low freq to high and it then drops off. Is that the point? I do not get another sweep of tone if I continue higher in the tuned in frequency.  I was expecting the zero beat to be between hearing the audio sweep below and above the zero beat.

Thanks,

Jeff
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WB6BYU
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« Reply #3 on: October 12, 2011, 08:56:08 AM »

Zero beat is when the frequency of the tone drops to zero.  It will be much stronger on one side
of zero beat than on the other due to the SSB filter in the radio, but you should still be able to
hear it when the calibrator signal is strong enough.  (Which side is stronger depends on whether
you are listening to LSB or USB.)

So as you tune through the signal from one direction you should hear a high frequency that gets lower
and eventually fainter as it gets below a couple hundred Hz.  If you keep going you will hear a fainter
signal at a very low frequency that rises back up.  (Or the faint/strong will be reversed, depending
on the direction you are tuning.)  Zero beat is that point of zero frequency in between the two slopes
where you don't hear anything - the rig is not particularly sensitive at that point (to provide carrier
rejection in the SSB signal) but you should be able to hear the calibrator on both sides if you listen
carefully.
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AC5UP
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« Reply #4 on: October 12, 2011, 10:22:51 AM »

I was expecting the zero beat to be between hearing the audio sweep below and above the zero beat.

What WB6BYU said regarding zero beating to the calibrator in SSB.

What you're thinking of ( Tone - Zero - Tone ) in symmetry as two signals pass each other while tuning will happen in AM and that's how you calibrate the calibrator. (!) Tune WWV at any frequency that's strong and steady then turn on the calibrator. You should hear no beat tone. If you do hear a tone, adjust the trimmer cap near the calibrator crystal to reach zero. In some cases you'll have to watch the S-Meter as it will wiggle near zero beat (tone goes subaudible) then hold steady at exact zero.

If the calibrator is on frequency and you can accurately zero beat to the calibrator you can be exactly on frequency anywhere.

Until the radio drifts, or you change bands..........................................  Wink
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WB6RXG
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Posts: 73




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« Reply #5 on: October 12, 2011, 12:18:41 PM »

When I was a novice in 1976 the dials on some VFOs tracked better than others.  The FT-101E that a friend owned was quite good.  The HW-101 that I owned wasn't quite as good and I swear it depended on the phase of the moon and the position of the planets not to mention how long the rig had been turned on.  However, all I used the crystal calibrator for was to locate the novice segment edges and stay away from them.  Band ans segment edges always fell on 25kHz multiples for example: 7.100MHz and 7.150Mhz.

In my opinion that's all the calibrator should really be used for.

You stated that stations you are working claim you are off frequency and that your clarifier/RIT is turned off and that you have tuned the VFO for a natural sounding voice.  Are they basing their statement on what  you sound like to them or from you telling them what the frequency of operation is and it differs from their digital readout?  If it is the former you need to determine what is causing the frequency shift between receive and transmit on the FT-101E.  If it is the later then stop telling them what you think the frequency is based on your VFO dial as it will never be accurate enough.  I don't remember much from the FT-101 manual but, I suspect that there is an adjustment for the clarifier/RIT off position that sets the transmit/receive offset to zero.

73,
Stuart
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W5FYI
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« Reply #6 on: October 12, 2011, 06:10:51 PM »

Stuart is right--the 101E's dial will get you close, and a "calibrated" calibrator will get you even closer, but the easiest thing to do is turn on the clarifier/RIT, give a few CQs and tune the clarifier for the best receive audio. After several QSOs you'll notice that the knob pointer is going to be in pretty much the same position. Leave it there and most of your QSOs will be dead on the other ops' frequency.

If you sign into a net, or act as net control station, you'll find you'll use the clarifier a lot. Leave your VFO alone, and use only the clarifier to fine tune the other stations when they come up off frequency.

A bit of history; in olden days, many VFOs rigs sent and received on the same frequency. An op would call CQ and get a reply, only the reply was a little lower in frequency, so he would retune for the best audio. The other op would hear the change, and tune lower for best audio on his side. When he transmitted, his frequency would, of course, be lower, so the first op would have to retune lower again. On it went, until one or the other (or both) found they were operating outside their band--and their frequency privileges. Thus, RIT was added to avoid stations leap-frogging each other.
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KC9QQM
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Posts: 181




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« Reply #7 on: October 12, 2011, 06:17:54 PM »

Thanks so much for the info. I now have a freq counter connected to the RF out before the finals and am able to now in transmit adjust to the exact freq and then use the clarifier for the good audio as you sugested. I also turned up the volume on the receiver when using the calibrator and am able to faintly hear that other sweep once I am past the zero beat. I will get on the air and see how I sound.

On the question that was asked, I was receiving the station ok but when I transmitted with the clarifier off I was told I was off frequency as to what they were hearing but as I think about it, this was on a foreign station (YL) and maybe they were working split.

How would I know that?

PS - I am going to go on 7.220 and call CQ a bit and see if any one interested and giving me a hand!!

Jeff
KC9QQM
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