[HCARC] Antenna noise

[SARA SANDSTROM]

Ray, 
  
The issue is not the high noise from your dipole.  Antennas aren't all equally efficient.  Mobile antennas are notoriously inefficient.  If one antenna is more efficient, the noise it receives will be stronger than the noise the inefficient antenna receives.  Does your receiver/transceiver have a preamp?  If it does, turn it off and see what the noise on the dipole is like.  The important thing is not S-meter reading but signal-to-noiose ratio.  Do the signals have the same SNR on the two antennas?  If so, turning off the preamp when you use the dipole may be all you need to do.  It is possible that the difference in polarization between the mobile antenna and the dipole is causing a stronger signal on the dipole or it may be the dipole is closer to the noise source than the mobile antenna but that isn't where I would start.  Do you hear the same signals on both antenna?  Do you hear more signals on one antenna or the other? 
  
If you have reasonably good antennas and receiver, you shouldn't need an RF preamp on ten meters or actually on any HF band.  The only antennas that really require a preamp are Beverage antennas, short whips (~1 meter tall) or small loop antennas.  45 years ago the best receivers had either very little RF amplification with extensive tunable RF and IF filters or no amplification before the mixer.  With the waves of "rice boxes" arriving on our shores, we seem to have forgotten what we used to know.  The rules still haven't changed, RF gain should be minimized in a truly high performance receiver.  
  
Let me know if you try these tests and how you make out.  I'll be happy to answer any questions. 
  
You will probably get a lot of different answers to your question.  Try everything 
  
Kerry, K5KS