[Hammarlund] SP600 - Reduced gain on 13kHz bandwidth

[kirklandb at sympatico.ca]

One thing to watch when doing power sweeps is to make sure that 
  a) AGC is off (which you indicated)
  b) make sure that you don't saturate/compress the amps (i.e. keep the input power low).

From: David_Wise at Phoenix.com
To: leslocklear at cableone.net; Hammarlund at mailman.qth.net; anchor at ec.rr.com; kirklandb at sympatico.ca; rrkrr at comcast.net; djed1 at aol.com; k9uw at wi-net.com
Date: Fri, 8 Jan 2010 09:28:47 -0800
Subject: RE: [Hammarlund] SP600 - Reduced gain on 13kHz bandwidth










Thanks for your comments.
 
I don't remember how the list treats attachments, so 
I'm explicitly
including everyone who answered.  Here are 
uncalibrated scope photos
of 3, 8 and 13.  Manual gain control, 
single-conversion,
sweeper injecting on mixer grid, scope monitoring IF 
OUT jack.
IF has been aligned.
 
Most people corroborated my observation, but one 
person
gets uniform gain.
 
Dave Wise


  
  
  From: Les Locklear 
  [mailto:leslocklear at cableone.net] 
Sent: Thursday, January 07, 2010 
  4:11 PM
To: David Wise; 
  Hammarlund at mailman.qth.net
Subject: Re: [Hammarlund] SP600 - Reduced 
  gain on 13kHz bandwidth


  
  Every SP-600 I have ever owned or operated 
  works like you described. Likewise every R-390A I have ever owned the carrier 
  level drops when switched to the 16 kc filter.
   
  Les Locklear
Hammarlund 
  HQ-180A
Hammarlund SP-600 Re-Engineered by John R. Leary
JRC 
  NRD-545
Ten Tec RX-350
   
  "As you wander through this world you see lots 
  of funny men.
Some will rob you with a six-gun, some with a fountain 
  pen."
   
  --Pretty Boy Floyd
   
  
 
  
    ----- Original Message ----- 
    From: 
    David 
    Wise 
    To: Hammarlund at mailman.qth.net 
    
    Sent: Thursday, January 07, 2010 4:51 
    PM
    Subject: [Hammarlund] SP600 - Reduced 
    gain on 13kHz bandwidth
    
I'm taking a second look for problems in my daily 
    runner.
One thing I noticed is that the gain on 13kHz bandwidth 
    is
about 1/3 that of 3kHz and 8kHz.  3 and 8 are equal.
The 
    manual shows a response curve where all bandwidths
peak at the same 
    gain.  It's too good, makes me suspect
someone just drew it 
    reflecting expectations.
I'd like to compare notes with other SP600 
    owners.
Does your signal strength reading stay the same from 3 to 8 to 
    13?

Thanks,
Dave Wise
SWL in Hillsboro 
    Oregon
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