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

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

ad: L-HROutlet
ad: l-rl
ad: abrind-2
ad: L-MFJ
ad: MessiPaoloni-1
ad: HRDLLC-2
ad: Left-2
ad: Left-3
ad: L-Geochron
  1. HS0ZED

    HS0ZED Ham Member QRZ Page

    Okay well I'm not going to worry too much about it. I see the fact that it reads the same as an external 50uV signal for both 100KHz and 25KHz as a bit of a bonus if anything. The board is a 'B' variant, not sure if they made other changes I haven't found a schematic for the 'B' version just the plain PB-1547 but it does seem to mostly agree with that schematic I think. And apart from some slight reduction in the calibrator signal on 160m, which I think might be something else, on all other bands it is a similar level. Quite remarkable that it could be faulty and that good!
  2. HAMHOCK75

    HAMHOCK75 QRZ Member

    I would check is to see if the divider is actually dividing by 128 to create 25 KHz and not for some reason stuck at dividing by 32 down to 100 KHz in both positions of the calibrator switch.
  3. G3YRO

    G3YRO Ham Member QRZ Page

    That's odd too . . .

    The calibrator should be strongest on 160m, and get weaker on every band as you go higher through the bands. And the 25kHz markers about 10dB weaker than the 100kHz ones.

    No, he as the board from an FT101B, not an FT101F.

    Roger G3YRO
  4. HAMHOCK75

    HAMHOCK75 QRZ Member

    I think he said he has the PB1547B version but only has the schematic for the plain PB1547. If you have schematic for the "B" version of the PB1547 might be interesting though.
  5. HS0ZED

    HS0ZED Ham Member QRZ Page

    Seems to be okay, good strong signal at all 25KHz points when the 25KHz calibrator is engaged. Only at the 100KHz points when that one is switched on.
  6. HAMHOCK75

    HAMHOCK75 QRZ Member

    I would be curious how strong you find the harmonic of the 100 KHz calibrator at 14100 KHz and 14300 KHz instead of 14200 KHz. If the divided down 100 KHz is close to square wave then the even harmonics like the 142th will be weaker than the odd ones at 141 or 143. If the 100 KHz is more like a pulse output, then there will not be as much difference.
  7. G3YRO

    G3YRO Ham Member QRZ Page

    Ah sorry . . . I thought you meant a board from an FT101B !

    Just connected up and checked my FT101F (which I've never really used . . . just bought it cheap a few weeks ago, and realigned it before putting it away)

    Setting the S Meter to read 50uV for S9, the 100kHz calibrator reads S9 +10dB . . . and that is on ALL bands, from 160 - 10m ! (unlike the E, where it is S9 +40dB on 160m, and drops off band by band, S9 +25dB on 20m, weaker on 15 & 10)

    The 25kHz calibrator signals are about 10dB weaker (as on the FT101E) . . . so on this rig, around S9.

    So obviously very much more constant harmonics . . . but lower level than on the earlier rigs.

    Roger G3YRO
  8. KA9JLM

    KA9JLM Ham Member QRZ Page

    Was the calibrator ever meant for checking signal level ?

    I thought is was for frequency cal only.

    The proper way to set S-Meter signal level is using the antenna input.
  9. G3YRO

    G3YRO Ham Member QRZ Page

    Yes, on these rigs . . .

    The calibrator has a known output, so can be used to set the S Meter sensitivity by the 99.9% of people who don't have access to a calibrated signal generator ! So it's quite useful.

    It's also all you need to re-align 95% of the tuned circuits in the FT101 . . . the only thing you can't use it for is to adjust the Traps.

    (it's just a shame that the revisions to the Handbooks for each of the FT101 versions haven't properly explained what is going on. When you set the S Meter against the stated level, that should correspond to S9 = 50uV)

    Roger G3YRO
  10. HS0ZED

    HS0ZED Ham Member QRZ Page

    Yes the radio is a late late FT-101E and by the boards fitted seems to be in fact the FT-101F. The cal board is the PB-1547B, but I've not found any infpo the differentiates the different PB-1547 versions.
    @G3YRO. Would be interesting to know which PB-1547 you have in the 101F. And it would be very interesting to see how it compares if you swap between the 2. Hmm.

    Quite remarkable that they got it that close to 50uV across such a wide range. Shame they didn't route it through the 20dB attenuator, that would have given you a strong signal and a reasonably weak one.

Share This Page

ad: cq2k-1