From: "DAN COTSIRILOS" 
Subject: Re: [drakelist] R4-C versus SPR-4 crystal frequencies and others


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The SW-4 uses the same offset as the SPR-4. I plugged a R-4C cb crystal =
in the SW-4 and it was so close I didn't even have to adjust the skirt! =
Beats me why they make them different the dial can more than make the =
difference anyway! Alot of stock crystals are off that much from each =
other so why even list 2 different kinds?  Dan
  ----- Original Message -----=20
  From: Herbert Schulz=20
  To: drakelist{at}www.zerobeat.net=20
  Sent: Thursday, February 12, 2004 1:16 AM
  Subject: [drakelist] R4-C versus SPR-4 crystal frequencies and others


  Hi all,=20
  i may have a silly question, but even reading the manuals=20
  carefully several times, i have not been able to find out=20
  what i'm asking for now:=20

  I'm owning an R4-C and an SPR-4 as well. Both appear to have=20
  exactly the same frequency scheme up to the 1st IF-frequency=20
  (PTO tuning range 4955[kHz] to 5455[kHz], 1st-IF frequency=20
  5645[kHz]). For me that leads to the assumption, that the crys-=20
  tal frequencies for the premixer-xtal-oscillator for the=20
  various bands should be absolutely identical in both receivers.=20

  However, in reality, the crystal frequencies in the SPR-4=20
  appear to have a -10[kHz] offset with respect to the R4-C=20
  (i.e. for 80[m], the XTAL in the R4-C is a 14.600[MHz] type=20
  and in the SPR-4 it's a 14.590[MHz] type). Does anybody=20
  know, where this -10[kHz] offset results from? Has anybody=20
  experience in intermixing the xtal's (of course, after placing=20
  them on socket adapters for HC6/U  HC18/U) for both of these=20
  receiver types?=20

  Furthermore i ask, if anybody has done the majority or all=20
  modifications on an R4-C as documented by VE3EFJ and is=20
  willing to tell me about the experiences? I want to par-=20
  ticipate from any experience before starting this big mo-=20
  dification project, as my R4-C actually is in an absolutely=20
  unmodified, original condition.=20

  Additionally, i'm looking for some parts to buy:=20
  - SPR-4: crystal calibrator, model SCC-4.=20
  - SPR-4: transceive adapter, model TA-4.=20
  - R4-C: 8-pole-crystal filter for AM, frequency 5645[kHz] (may=20
          be of the same type as for the R7/R7A, but i don't=20
          know that for sure).=20
  - MS-4 speaker in mint condition.=20
  - FS-4 frequency synthesizer.=20
  If somebody has something to offer, please let me know (if=20
  possible, including the approximate estimated shipping charges=20
  to Germany).=20

  Latest: Does anybody know, if there is a GOOD (i.e. low phase=20
  noise) DDS-based frequency synthesizer for the R4-C/SPR-4 etc.=20
  on the market? I'm looking either for a well documented sche-=20
  matic, or a kit, or a affordable ready-to-use unit. The only=20
  thing i found regarding this item is a japanese home page,=20
  but besides the schematic and the photo's, i - obviously -=20
  did not unterstand one word.=20

  This was a lot of stuff - thank you all for your attention and=20
  patience. Thanks in advance for all your answers and respon-=20
  ses and the associated efforts.=20

  vy73, DG7MCC=20
  Herbert=20
   =20


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The SW-4 uses the same offset as the SPR-4. I =
plugged a R-4C=20
cb crystal in the SW-4 and it was so close I didn't even have to adjust =
the=20

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