[1000mp] AFSK/SSB Power Drop

[Thomas Giella KN4LF]

When you get the transmit power output drop does your digital readout dim and/or flicker? If so you are getting RF feedback from your nearby indoor loop. 

Add 1/4 wave radials for all bands you operate on to the back of your tuner and see if that helps. Also does your external tuner have a built in 4:1 BALUN? If so are you using it? By using it you "may" be able to reduce the RFI problem, by forcing current in both sides of your feedline to be "more" balanced. Of course though on certain bands at certain powers the BALUN "could" saturate and create problems.

If it is an RFI problem it Can cause your Mark V to do a hard reset and you will lose all menu settings, auto tuner and memory data.

73,
Thomas F. Giella, KN4LF
Plant City, FL, USA
Grid Square EL87WX
Lat & Long 27 58 31 44N 82 09 51 98W
kn4lf at arrl.net

KN4LF Solar Space Weather & Geomagnetic Data Archive: http://www.kn4lf.com/kn4lf5.htm
KN4LF Amateur & SWL Radio History: http://www.kn4lf.com
  ----- Original Message ----- 
  From: Chris Brougham 
  To: All about Yaesu 1000mp 
  Sent: Saturday, August 21, 2004 3:51 AM
  Subject: [1000mp] AFSK/SSB Power Drop


  Hi Folks,

  I've been noticing a strange problem with my Mark V. Every now and then 
  I will get power drops when using afsk RTTY or phone. The SWR is always 
  flat so I don't think it's that (I use an external tuner). I never see 
  the problem with CW. When the power drops out I often have to power cyle 
  the rig to get it working again ... but not always.

  I have a couple of different types of antennas at this QTH (an 
  apartment). One is a large indoor wire loop fed with 450 ohm ladder 
  line. The others are a mag loop, fed with coax, and one is a hamstick 
  mounted on my balcony.

  I've never seen the issue with the hamstick, but it occurs most 
  frequently with the indoor wire loop. I noticed it on 40M phone during 
  Field Day with the wire loop for the first time. Yesterday I noticed it 
  on 15M phone (running 20 Watts). Today during the SARTG RTTY contest it 
  occured for the first time with the mag loop running 75 watts (all the 
  other occasions were with the indoor wire loop).

  My friend suggested some sort of RF problem in the shack. Why would it 
  occur only on phone and AFSK and not CW? It seems to be intermittent too.

  Any ideas would be really appreciated!

  -- 
  Chris VA7CAB



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