[TowerTalk] Screwdriver antenna on the porch roof

[David Jordan]

Hi folks,

Was visiting a ham buddy today.  He has a Hi-Sierra El Dorado. on 75m 
the antenna loads great as per the MFJ 259.  But when we put the juice 
to it from the ICOM 746 the ICOM shows a very high swr.  However, when 
we engage the auto-tuner in the 746 the rig loads up the antenna in a 
heart beat.  On 40-10m the antenna works fine with the ICOM...no tuner 
needed.  The readings on the MFJ on 40-10m were achieved in the same 
method used for 80m, simply move the coil to the position where SWR was 
1:1, etc. On 40-10m the readings on the MFJ and the readings on the ICOM 
746 were identical. However, no problems exist on the 746 on 40-10m.  

Any ideas why 80m is acting strange?  Is this a 746 proclivity?

thanks,
dave
wa3gin