On 160 meters, the PTO (5.0 to 5.5 MHz) adds to the 5.8 MHz crystal to produce
10.8 to 11.3 MHz. The the 9.0 MHz IF is subtracted from this signal to receive
the incoming signal (2.3 to 1.8) MHz. On this band, as the PTO frequency goes
up, the TX/RX frequency goes down.
On 80 meters, the PTO (5.0 to 5.5 MHz) adds to the 7.5 MHz crystal to produce
13.0 to 12.5 MHz. The the 9.0 MHz IF is subtracted from this signal to receive
the incoming signal (4.0 to 3.5 MHz). On this band, as the PTO frequency goes
up, the TX/RX frequency goes down.
On 40 meters, the PTO (5.0 to 5.5 MHz) adds to the 11.0 MHz crystal to produce
16.0 to 16.5 MHz. The the 9.0 MHz IF is subtracted from this signal to receive
the incoming signal (7.5 to 7.0 MHz). On this band, as the PTO frequency goes
up, the TX/RX frequency goes down.
On 30 meters, the PTO (5.0 to 5.5 MHz) adds to the 13.99 MHz crystal to produce
18.99 to 18.49 MHz. The the 9.0 MHz IF is subtracted from this signal to
receive the incoming signal (9.99 to 9.49 MHz). On this band, as the PTO
frequency goes up, the TX/RX frequency goes down.
On 20 meters, the PTO (5.0 to 5.5 MHz) subtracts from the signal to convert the
14.0 to 14.5 MHz to the 9 MHz IF. No band crystal is used. On this band, as
the PTO frequency goes up, the TX/RX frequency goes down.
On 18 meters (incorrect marking for 17 meter band), the PTO (5.0 to 5.5 MHz)
could go either way because the crystal frequency is incorrectly marked in
schematic. I don’t know its frequency so cannot calculate its tuning direction
on this band.
On 15 meters, the PTO (5.0 to 5.5 MHz) adds to the 6.99 MHz crystal to produce
11.0 to 11.5 MHz. The the 9.0 MHz IF is added to this signal to receive the
incoming signal (20.99 to 21.49 MHz). On this band, as the PTO frequency goes
up, the TX/RX frequency goes down.
On 12 meters, the PTO (5.0 to 5.5 MHz) adds to the 10.5 MHz crystal to produce
15.5 to 16.5 MHz. The the 9.0 MHz IF is added to this signal to receive the
incoming signal (24.5 to 25.0 MHz). On this band, as the PTO frequency goes up,
the TX/RX frequency goes down.
On 10 meters position A, the PTO (5.0 to 5.5 MHz) adds to the 13.99 MHz crystal
(the same crystal used on to produce 30 meters) to produce 19.99 to 21.49 MHz.
The the 9.0 MHz IF is added to this signal to receive the incoming signal
(27.99 to 28.49 MHz). On this band, as the PTO frequency goes up, the TX/RX
frequency goes up.
On 10 meters position B, the PTO (5.0 to 5.5 MHz) adds to the 14.49 MHz crystal
to produce 19.49 to 19.999 MHz. The the 9.0 MHz IF is added to this signal to
receive the incoming signal (28.49 to 28.999 MHz). On this band, as the PTO
frequency goes up, the TX/RX frequency goes up.
On 10 meters position C, the PTO (5.0 to 5.5 MHz) adds to the 14.99 MHz crystal
to produce 19.99 to 20.49 MHz. The the 9.0 MHz IF is added to this signal to
receive the incoming signal (28.99 to 29.49 MHz). On this band, as the PTO
frequency goes up, the TX/RX frequency goes up.
On 10 meters position D, the PTO (5.0 to 5.5 MHz) adds to the 15.49 MHz crystal
to produce 20.99 to 21.49 MHz. The the 9.0 MHz IF is added to this signal to
receive the incoming signal (29.49 to 29.999 MHz). On this band, as the PTO
frequency goes up, the TX/RX frequency goes up.
In all cases, the counter simply corrects its preset to give the correct
readout. An analog dial would need a dual scale to work with this scheme. The
only difference is that the knob goes the opposite direction on the higher
bands than on the lower bands.
40 meters SHOULD tune the same direction as 160…
One other error in the schematic is that the local oscillator is shown
connected directly to the FET power supply line (regulated as well) and
bypassed to ground via a 0.01 uF capacitor. This can’t work…
Gary
W0DVN
> On Aug 26, 2018, at 2:07 PM, Duane - N9DG via TenTec <tentec@contesting.com>
> wrote:
>
>
>
> A test that would be interesting to see is if the behavior of how the CW
> signals tune behaves the same way when the mode switch is set to SB-N and
> then SB-R. They should behave differently from each other, one should tune
> like you expect CW to tune. And the other the way you now see CW tune.
>
> If SB-N and SB-R behave as expected then there's a very good chance that one
> of the connections between the Mode switch and DSB board is not making the
> needed connection when in CW mode. In any case it would be well worth the
> time and effort to check the interconnection wire connections between the
> Mode switch and the DSB board.
>
> After looking at the block diagrams and schematics it looks like that CW
> should tune as if the radio is in CW-N, if the mode is set to CW-R it should
> tune the opposite way, and the way you are describing.
>
> So the suggestion that the problem is in the Double Sideband Board (DSB), or
> the wiring to it, I think is correct. But it should be noted that in the
> Corsair II there is just one crystal that is placed above and below the IF
> filter passband by capacitor that is switched into the BFO oscillator circuit
> by the positions on the Mode switch. And in the case of the CW tuning the
> wrong direction is because that crystal is not running at the right frequency.
>
> So the issue is not related to the PTO or the LO oscillator mixer boards.
>
> Duane
> N9DG
>
>> On Aug 25, 2018, at 12:17 PM, Paul DeWitte <k9ot@yousq.net> wrote:
>>
>> I am not sure how to explain my problem.
>>
>> I have 3 corsair IIs. recently I got one out to give it some air time. It
>> had been a while since it had been used.
>>
>> When tuning in a signal on 40M I found that instead of turning the VFO
>> CLOCKWISE to zero beat on a low pitch signal, I have to go down (counter
>> clockwise) to get on frequencey. The offset tuning works the same way. I
>> have to tune down to bring the signal up in pitch.
>> That is exactly backwards of how TT radios work on 1.8 to 10 MHZ.
>>
>> Everything else seems to be correct. The frequency readout seems to be
>> correct as you tune up the band.It has good rcv audio, and this is the only
>> thing that I find wrong.
>>
>> Is there a wiring problem here? In looking at one of the others, I do not
>> see any difference in wire routing.
>> Can it be the PTO?
>>
>> Thanks for any replies,
>> 73 Paul K9OT
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