Sherwood Sync

[aa5wg]

Can the Sherwood Snyc. be use with a boat anchor while operating SoftRock?
Chuck

[Steve - K4HX]

Sure. Both take the IF out. As long as having both connected does not load the IF, you're golden. If loading occurs, a buffer amp will be needed.

This would be a nice way to compare and contrast the two.

Can the Sherwood Snyc. be use with a boat anchor while operating SoftRock?
Chuck

[aa5wg]

Hi Steve:
When using the Sherwood Sync. with a "Boat Anchor" (Drake R-4C) which part of the IF does one tap, i.e. 1st IF or 2nd IF?  And, which part of the radio dose one tap the signal for SDF?  I was wondering if I could get the Drake to receiver SDR? 

But, I did not want to loose the 1st and 2nd IF selectivity of the Drake crystal filters.  I was wondering is it possible to use the radio 1st and 2nd IF filters with the SDR filter system from the computer and with the advantage of the Sherwood Sync?

Chuck

[Steve - K4HX]

I'm pretty sure the Sherwood is limited to 455 kHz IF only. If you build your own SoftRock, you can make it for any IF frequency. Buddly - WD8BIL has connected a SoftRock to a Drake, so I'll let him chime in on the particulars for that radio.

[w3jn]

You should always tap the last IF for either, unless you want to use the SDR for a panadapter, then tap just after the first mixer.

Sherwood makes little downconverter boards to go with the SE-3 so it'll take any IF.   Or you can order it for any IF.  The downconverter boards are pretty expensive, you could easily make one with a NE602 and the appropriate crystal.

[aa5wg]

Steve, W3JN and all:
So, I tap after the last IF, i.e. 2nd IF, for either SDR or Sherwood Sync.
If I do it this way will I not have any screen shots at the received SDR stations?

I known little about Panadaptors.  Is this the same as the water falls when looking/receiving SDR stations?
Chuck

[w3jn]

If you are using a Softrock, that has no frequency agillity and you are primarily going to use it for its demodulation, tap at the secondary of the last IF stage.  If you are using a tunable SDR, for instance, a SDR-IQ, and want to examine a wider bandwidth on the waterfall (ie use it as a panadapter) then I'd tap just after the first mixer.

[aa5wg]

W3JN and all:
Thank you. 
Chuck

[N6YW]

Bravo.
Excellent thread here. After reading this, I began to realize that my 75A-4 could be vitalized and much more usable. Although it is a great radio, I have my complaints and the same goes with my R-390.
Would you be so kind as to point me to where I can find the subject on modifying the 75A-4, removal of the 6AQ5 output stage/interface? Also, they mention the R-390-A on the website, but not the 390. Am I correct in assuming the interface scheme is the same? I imagine the SP-600 would benefit from this as well.
Thank you.
Billy N6YW

[w3jn]

Yep.  Connecting the diode load or the SE-3 would be the same for the R-390 or R-390A.  Both flavors have an IF output jack.

As far as the 75A-4 goes, just tap at the detector load (where the audio signal goes to the vol control or first audio grid).

[N6YW]

Yep.  Connecting the diode load or the SE-3 would be the same for the R-390 or R-390A.  Both flavors have an IF output jack.

As far as the 75A-4 goes, just tap at the detector load (where the audio signal goes to the vol control or first audio grid).

So, a simple shielded cable from the volume control to a jack, and pull the 6AQ5 right?

[w1vtp]

Just hooked up a SE-3 and it is really great.  Both my SP-600 and SX-73 have IF outs.  just turn down the onboard audio on either RX, hook the AUX from the SE-3 to a HIFI line level and viola!  Really Really great audio.

Al

[WD8BIL]

Buddly - WD8BIL has connected a SoftRock to a Drake, so I'll let him chime in on the particulars for that radio.

I've got the Softrock on the R4A. I took the first I.F. (5645kHz) cause the second is 50kHz and I wanted to see more spectrum than that. A buffer amp was needed to maintain the R4A stock performance.
I know the R4C has more solid state stuff in the I.F. than the A version so I'd hafta look at the skitzo before recommending anything.

[aa5wg]

W1VTP, WD8BIL:
Nice to see the SE working and great on the R4A. 
Chuck

[k4kyv]

Yep.  Connecting the diode load or the SE-3 would be the same for the R-390 or R-390A.  Both flavors have an IF output jack.

As far as the 75A-4 goes, just tap at the detector load (where the audio signal goes to the vol control or first audio grid).

So, a simple shielded cable from the volume control to a jack, and pull the 6AQ5 right?

You need to pull the i.f. signal off the last i.f. stage.  It takes only a few picofarads of coupling capacitance to over drive the SE-3. I don't have the 75A-4 schematic in front of me here, but recounting from memory, I pulled out the 6AL5 diode detector, and inserted the probe into the socket pin that connects back to the i.f. transformer.  The coupling cap is connected in series with the probe pin and the shielded lead going to the SE-3. The shield connects to a grounded pin.  The noise limiter and receiver audio amplifier are completely disabled, and so is the normal passband tuning operation, since the BFO now locks onto the AM carrier and is no longer shifted in step with the main oscillator when the PBT control is adjusted.  I removed the 6AQ5 and set it aside, for less heat generation and unnecessary drain on the receiver power supply. In CW/SSB mode (manual control of the SE-3 BFO), the passband tuning function requires two-handed simultaneous adjustment of the PBT control on the receiver and the SE-3 BFO pitch control.

One could pick off the i.f. signal without removing the tube (maybe something as simple as wrapping one lead of the coupling capacitor round the tube pin) and still  have the stock functions of the receiver, but I found my way less hassle.

A shielded lead to the volume control or 1st audio grid won't pick up anything the SE-3 can use.  You have to tap onto a point between the last i.f. stage and either the diode or stock product detector in the receiver.

[kg8lb]

Kiwa:

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