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FT-101E Intermittent Audio level/S-Meter level

Discussion in '"Boat Anchor" & Classic Equipment' started by KB3GWQ, Jun 26, 2018.

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  1. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    OK. So I'm using my IC746PRO which I know is pretty close to where it should be on frequency stability. RBN CW has confirmed and I've worked very narrow 50-250hz plenty of times.

    Have you ever looked at the output on waterfall scope? Try this... download Speclab and run speaker out to your line-in from your 101e. Where does the filter start and end?

    Attached is a picture showing where my signal (the 800hz) is and me transmitting back to myself on the 746PRO notice how far away it is. If I turn the USB RX I can get it close but then notice how the filter shifts. This also affects the general noise level I have noticed and is no longer consistent with LSB/USB settings on where the filters begin/end.

    Capture1.PNG

    Second picture is now adjusted to be pretty close to each other
    Capture2.PNG
    Notice now how my tone and the receive tone is now on the edge of the filter. This is no good. Have you ever verified if you transmit dead-on say 14.100 into a dummy load then transmit back to yourself and viewing it in a waterfall display like this to see if its actually zero beated?
     
  2. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    I did some more experimenting and the tightest offset I can get between them with this (about 550hz apparently) is about 300-400hz. My guess is that either a larger value trimmer cap is needed (or will this make no difference?) or a component related to this has drifted in value like a resistor and must be replaced? Or, this is about as good as it gets stock on CW. It's not a huge loss as I just have to bump the clarifier knob a tiny bit but would be nice to get it tighter if possible.
     
  3. G3YRO

    G3YRO Ham Member QRZ Page

    I can't make sense of your waterfall display . . . or exactly what you are saying!

    For example:
    But you want the offset to be 800 Hz! (or whatever exact frequency your Sidetone Osc is)

    Firstly, are your LSB and USB carrier crystals set correctly?

    If so, when you tune in a signal in the CW position (use the Calibrator as a test signal), at what audio tone are the edges of your CW Filter? It should fall off when the audio tone is about 500 Hz on the low side, and 1100 Hz on the high side. (ie about 600 Hz wide, centred around 800 Hz).

    Is this correct on your rig?

    And secondly, you should have plenty of range on the CW Trimmer to adjust the CW offset to match the 800 Hz of the Sidetone Osc . . . but I'm not sure (from your description) if you are tuning in correctly. When you tune in the test signal on receive, are you first exactly matching the pitch of the Sidetone Osc?

    If so, how near the test signal can you get the CW Tx signal when you adjust the Trimmer?

    Roger G3YRO
     
  4. HAMHOCK75

    HAMHOCK75 QRZ Member

    That suggests R2 ( 22K ) is open circuit. The 3SK40 has a spec. that the absolute maximum G1 voltage is +7 VDC.

    https://datasheet.octopart.com/3SK40-NEC-datasheet-106197.pdf

    That spec. is because dual gate mosfets like the 3SK40 typically have back to back diodes as shown in the above spec. sheet to protect the gate from transients that exceed about +/- 10 volts. When the protection diodes turn on, they essentially short out any signal on G1.
     
  5. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    I must have explained this wrong. The LSB and USB carrier crystals APPEAR to be set correctly (or close to it). I have worked USB Phone a few times with no complaints but will test it again. The audio edges are in the pictures. See in the top photo the waterfall begins around ~450 and ends at ~1100hz. The 800hz is relatively centered to it. So yes, that is correct. And last night I was on 160M LSB and I was told I was exactly on frequency and holding it.

    If I match the exact pitch of the the calibrator (yes?) to 800hz then TX will be under the exact frequency by about 200-250hz. And this is with the CW trimmer at it's maximum. Turning it any more will lower it more. I can not get it any tighter. So, for me I found the way to compensate for this is to set the calibrator around 1100-1200hz and use the clarifier to get it back to 800hz and then I will be pretty close. I know the 101e is off because I checked it on the 746PRO and when I first started using the rig I noticed most people responding to me were either just on the top edge of the filter or a little past that where I had to use the clarifier to find them. Because of this, I think there may be a component that has drifted in value on the PCB with the CW TX offset trimmer. But what would it be? And just to note it's not a band specific problem or anything like that. It may even be possible that the radio is just like this, but I have no idea. It's hard to tell sometimes because people I run into locally just say things like "Oh well they were all off frequency and drifted, etc. back in those days". But I doubt that they were off this far on a hybrid model. Maybe some old kit or a true boat anchor but I don't consider a 101E a true boat anchor.
     
    Last edited: Jul 4, 2018
  6. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    OK, will look into it Friday and let you know. My ratshack soldering iron has finally bit the dust so waiting on a new Weller to show up from Amazon.
     
  7. G3YRO

    G3YRO Ham Member QRZ Page

    OK . . . I get your Waterfall Display now . . . . you are just looking at Noise, and the Pink area is the received Noise, and the Blue is nothing.

    However . . . I suspect your USB crystal is not set correctly. (it could easily be 200 Hz off optimum, yet people still saying your Tx audio sounds "OK" !)

    The easiest/best way to set the Sideband crystals is to use the calibrator as a reference oscillator.

    Tune in on USB so the audio note is about 1 kHz . . . adjust the Preselector so the S Meter reads S9 +10dB.

    Now turn the dial so the pitch of the signal goes lower . . . find the point where the S Meter reads exactly S9. Now adjust the USB Crystal Trimmer until the Audio note out the speaker is 200 Hz. (Do you have a frequency counter you can plug into the audio output? If not, can you estimate 200 Hz? See what 200Hz sounds like on your rig with a digital display).

    Then set LSB the same way.

    THEN . . . see whether the CW Tx crystal will now adjust to give you an 800 Hz offset (it should also be roughly in the middle of your 600 hz CW Filter passband)

    Let me know how you get on.

    Roger G3YRO
     
  8. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Roger. I don't have a frequency counter or generator. But, I will be able to see where 200hz is on the waterfall display no problem and that speclab is pretty accurate as long as your sound card does not have a drift issue (mine doesn't).

    So how do you know when you're locked in dead-on with the calibrator anyways? Do you just tune it until the tune get's lower and you can't hear it anymore? I'm not sure if that's accurate. At least it does not appear that way on CW.

    If you're able to hook your radio up to speclab in the waterfall you would be able to tell where the filter begins and ends for SSB and CW. I'm curious to know what a properly aligned 101 would say. It appears like the filter starts around 200hz or so for SSB at least on my rigs.
     
  9. KB3GWQ

    KB3GWQ Ham Member QRZ Page

    Also, my S-Meter might need slight adjustment. I think you just go to a certain frequency on 20m and tune it for S9+25db, yes? I did that and it seemed like some stations that were S9 were more like S9+20 for me when I was listening to them on 80m compared to my IC-746PRO. But, it's possible that modern rigs S-Meter's aren't as accurate (which is a complaint I see on eham, but hams like to complain so it's hard to say for sure without the proper tools!).
     
  10. G3YRO

    G3YRO Ham Member QRZ Page

    EDIT - yes - To set the S Meter calibration, connect a dummy load to the rig. Go to 14.200 and tune in the Calibrator with the switch in the 100kHz position (not 25kHz) . . . peak the Preselector for maximum signal - set that to read S9 + 25dB.
    You're not reading what I said properly !

    You adjust the dial to the point where you are 10dB down the filter response, in the way I explained.

    THEN you adjust the USB Crystal Trimmer up or down until the audio tone is 200 Hz.

    Then repeat for the LSB crystal.

    Roger G3YRO
     

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