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First rig without TXCO alignment... off frequency?

Discussion in 'General Technical Questions and Answers' started by KE0EYJ, Aug 7, 2019.

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  1. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    I have never owned an older rig that had the option of purchasing a TCXO alignment addition, or drifted. I now have a used TS480SAT, and I've noticed that this morning it is off frequency by .11 on 15m, 17m, and off by about .08 on 20m and .04 on 40m.

    Is this normal operation on a rig that does not have a TCXO module installed -- is this a small amount of drift, or just out of alignment somehow? Does this change as it warms up? I didn't notice this behavior last night. Is there likely a problem with this used rig, or is this normal?

    This is the 2nd day using the radio.
     
    Last edited: Aug 7, 2019
  2. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    ".11" what?

    14.110 Mhz?
    14.110.110 Mhz?

    110 Hertz (0.110 MHz) (0.000.110 Mhz) isn't far off. And yes, I would consider that within typical range of accuracy for a modern radio without a high precision oscillator. I would not expect any radio made in the last 30 years to have noticeable warmup drift.

    Reminder: While I'm not on Social Security yet, I started with a Heathkit SB-102 that did have about 300 KiloHertz drift on 30 minute warmup and required the dial to be calibrated against the internal marker on each band change or when moving from one end of a band to the other.

    shrug. How much precision do we need for general operating on CW/Fone? Probably within 3Kc's is close enough, realistically. The old, old timers did it!
     
    Last edited: Aug 7, 2019
  3. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page


    Yes, that's about how much it's off. Have had the radio on for an hour, and no change, though.
     
    KA0HCP likes this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    0.110 MHz would be wildly far off. 110 Hz is 0.000110 MHz.:)

    110 Hz "off" is more than I'd expect from a modern rig, but would have been considered amazingly accurate only 40 years ago.

    Sounds like something drifted with age, if it's really that far off. My old Ten Tec Jupiter, which is now at least ten years old, is still "dead zero beat" with WWV from a cold start and it doesn't have a TCXO. TCXOs are most useful in environments with large temperature changes; the design doesn't necessarily assure "accuracy" so much as it assures "stability" with temperature change.
     
    WA7PRC likes this.
  5. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    So what would be required to make this rig right?

    I'm sittiing on 21.205.10 to correctly hear someone who would normally be on 21.205. Happening with all contacts I'm hearing on all bands but 40m, where it's closer to true.

    I got this rig used, and if it's "wildly far off" then I'm wondering if I should return it.
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Assuming it's not "cockpit error," like you have the RIT turned on when it shouldn't be, that is more error than I'd expect.

    I'm not a TS-480 expert by any means and never owned one. Maybe Clif KA5IPF, who is, can chime in and advise on this -- whether this is common or not, and how to correct it.
     
  7. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    RIT isn't on accidentally -- I am using it to compensate, though. Luckily, the 480 has that large and in charge at the top, so correction is easy.

    If my Korean is right, the local Kenwood fix-it guy (he works on older kenwoods) said he can align it for $30 and have it done in a day. I can live with that.
     
    Last edited: Aug 7, 2019
  8. WA9UAA

    WA9UAA Ham Member QRZ Page

    You might try a full reset just to see if it corrects anything.
     
    KE0EYJ likes this.
  9. W4KJG

    W4KJG Subscriber QRZ Page

    I'm curious how you know it is off frequency. Listening to a SSB or CW signal, which may or may not be on frequency, I'm not sure how you can tell that you are a few tens of Hz off frequency.

    To know if it really is off frequency, you need to compare it to a known reference signal. Being in Korea, you probably cannot tune to WWV or CHU. However, most broadcast shortwave broadcast stations are very accurately on frequency. Your rig has a feature that eliminates beats. Make sure it is off if you are trying to zero beat to a frequency standard signal.

    I downloaded the manual and specs for the TS-850SAT. The documentation does not list the frequency accuracy for your model. However, the numbers you provided are within the specifications for your unit as you say it is configured. With your master oscillator, you can expect +/- 10 ppm. That translates to +/- 100 Hz at 10 MHz.

    You can purchase Option SO-3, which is stable to +/-1 ppm over temperature. In household use, it should be well within +/-0.5 ppm. That translates to +/- 5 Hz at 10 MHz (+/- 2.5 Hz @ 5 MHz, +/- 10 Hz @ 20 MHz).

    It is unfortunate that the manufacturers are showing frequency readouts to 1 or 10 Hz. For most amateur radio uses, an inaccuracy of a few tens of Hz amount to nanoscopic adjustments.

    If you should desire more information about your transceiver, I will be glad to evaluate it for free. It should take less than 24 months to complete the evaluation. I would need the original master oscillator and the Option SO-3 option.:cool:
     
    WA7PRC, N1DQQ and KE6EE like this.
  10. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    1/10th is plenty to notice. I can hear a distinct difference from as little as .03 to .04, actually. Frankly, I don't see how someone could not notice. It doesn't affect comms there, but by .10, it does become bad enough that one op will need to adjust in a rag chew.

    I can tell easily, because voices sound funny... high pitch like a chipmunk, until I correct it. I will post a video. I have owned 8 other rigs and never encountered one off by this much.
     
    Last edited: Aug 7, 2019

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