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

skirt! Beats me why they make them different the dial can more than make =
the=20
difference anyway! Alot of stock crystals are off that much from each =
other so=20
why even list 2 different kinds?  Dan

  ----- Original Message
----- 
  From:=20
  Herbert">mailto:herbert.schulz{at}schulz-systemtechnik.de">Herbert =
Schulz 
  To: drakelist{at}www.zerobeat.net=">mailto:drakelist{at}www.zerobeat.net">drakelist{at}www.zerobeat.net=
 
  Sent:
Thursday, February 12, =
2004 1:16=20
  AM
  
Subject: [drakelist] R4-C =
versus SPR-4=20
  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 =

  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=20
  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 =

  (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 receiver
types?=20
  Furthermore i ask, if anybody has done the majority or
all =

  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- =

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

---