[Elecraft] K3 - Receiver desense?

[Jeff Cochrane - VK4BOF]

Thanks to you all for the replies so far.
Further information for everyone:
1. Yes, the radio was turned off before the cars engine was shut down. (On several occasions)
2. The second battery was in no way connected to the cars charging system or to any other part of the cars wiring, it was just sitting in the tray of the ute and had been lightly used for the field day.
3. I suspect that the lights flickering on the radio had more to do with using wiring that was not capable of carrying 20+Amps (The wiring used is normally used for powering the 2M rig which draws no more than 10A. (It was just a test after all, I simply unplugged the lead from the 2M set and connected the K3's power lead to it.) I am more concerned with the almost total loss of receiver sensitivity.


Jeff Cochrane - VK4BOF
Innisfail, QLD, Australia

  ----- Original Message ----- 
  From: Chuck Shefflette 
  To: Elecraft Elecraft List 
  Sent: Tuesday, April 05, 2011 9:46 AM
  Subject: Re: [Elecraft] K3 - Receiver desense?


  I'm betting the battery voltage was low enough that the alternator voltage couldn't get it stable, the bigger battery took care of the regulation and everything was happy.

  73,
  Chuck AA3Cs
  On 04 Apr 2011, at 19:40, Fred Jensen wrote:

  > Hmmm ...
  > 
  > Not that I'm suggesting you try and recreate the "experiment" Jeff, all 
  > sorts of undesirable electrical effects occur on the 12V power in a 
  > vehicle when you start it, but possibly some sort of transient scrambled 
  > the K3.  I shouldn't do it, but I often start my truck with the ICOM 
  > IC-4300H still on.  About half the time it reboots, the other half it is 
  > fine.  I think the factory recommended method to shut down your K3 is, 
  > "Turn it off," then do whatever you want to with the power supply.  Just 
  > a thought.
  > 
  > 73,
  > 
  > Fred K6DGW
  > - Northern California Contest Club
  > - CU in the 2011 Cal QSO Party 1-2 Oct 2011
  > - www.cqp.org
  > 
  > On 4/4/2011 4:06 PM, Jeff Cochrane - VK4BOF wrote:
  > 
  >> Whilst parked up in the car and with the K3 running on 15M during CQ WW SSB I noticed that the display lights were flickering alot on TX, indicating to me that maybe it was time to start the engine to increase voltage to the rig.
  >> Received sigz at the time were plentiful (crowded) and loud, the band was wide open.
  >> So, I started the engine and all sigz but for a couple of what used to be loud signals had disappeared!
  >> The really loud sigz I had heard before were considerably reduced in volume and signal strength.
  >> I checked the NB and NR settings and found that both noise blankers were both turned off as was noise reduction off.
  >> I tried both NB's and neither were of any use.
  >> There was no type of noise heard on the radio at all apart from the usual (low down) band noise.
  >> All the above was noted when I was using the cars own battery / power system.
  >> 
  >> I shut down the engine and all sigz came back to normal.
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