[Hammarlund] questions for sp600-jx26?

[James A. (Andy) Moorer]

Hope you don't mind me posting this to the group as well.
  ----- Original Message ----- 
  I'll take that transformer. Can I paypal you? If so, is this the email to use? Do you generally mount it within the sp600 or external to it? Also, what gives with the different outputs (diode, etc)? 



OK. PayPal to jamminpower at earthlink.net

Give me a mailing address sometime.

About mounting the 600/8 ohm transformer,  it depends on the setup. If you can mount it in or near the speaker, then do it there. Otherwise, a little box with speaker terminals on both sides will do (be sure and mark which end is which!). I wouldn't try to mount it inside the SP-600. Among other things, it might cause a bit of astonishment to the next owner (since we know that a well-maintained SP-600 will outlast all of us!).

There are two other outputs: diode output, and AVC voltage. Both are really more for diagnostic use than anything. If you are trying to do a diversity setup, you can connect the diode outputs and the AVC outputs of two receivers together. The stronger output will come through the diode output, and thus to the speakers of the receivers, and the AVC voltage will attenuate the weaker receiver so the stronger signal will dominate. Later, the JX17 was made with even more connections so that two receivers would tune in lock-step as well (uh, well, sorta - you still have to manually tune the RF stages, even though the VFO is bypassed in diversity/slave mode).
  As for the power receptacle, that sounds like a tough job. I wonder if someone makes a jig/punch like the db25 punches or round punches. You know, drill a hole, put the punch through and then tighten the bolt. (I think greenlee is the mfg I know that made punches).

Seems like there should be. I sometimes start with a 3/4" square punch, then just nibble out the rest. I haven't found a punch of exactly the correct shape yet. If you find them, get one for me.

  IF: The IF out on the back of the radio -- you noted that this is good for an ssb adapter but not panadapter. Is this because this is a post-filter output? And that there is too little bandwidth available to be useful on a panadapter?

That is exactly correct. It is after 6 tuned circuits. There isn't much bandwidth left.

  Also, I seem to recall reading that the sp600 is dual conversion, ie two different IFs. Would a panadapter need to support both IFs? Or do they always convert down to 455 regardless of what band your on?

If you pick it off the 2nd mixer output, it is all 455 kHz. No problem.

The SP-600 is only dual conversion on the upper bands, where it is 3.955 MHz. That is immediately down-converted to good ol' 455 kHz.

James A. (Andy) Moorer
www.jamminpower.com