[SCCC] Antenna Challenge

[Glenn Rattmann]

(Mark, you mean CQ 160 and not ARRL 160...)
I agree with Mike's thoughts.
I would also put some clamp-on beads on the RG213 from radio to input of tuner.
If you don't have those available, replace the coax driveline with 
one much longer than the short one you have in there.
Coil up the excess coax to make a common-mode choke (6-8 inch 
diameter coil bundle, so you need 1.5 - 2ft per turn).

Good luck!

Glenn K6NA

At 09:20 AM 1/24/2019, Michael Tope wrote:
>This is a longshot, Mark, but I wonder if LDG is trying to match 
>your antenna at a harmonic of the input frequency. Do you happen to 
>have a standalone impedance analyzer (e.g. an MFJ-269) that you 
>could use to sweep the input of the LDG after it tunes up (with the 
>IC-7600 driving it) and indicates the 1.3:1 VSWR across 160 meters?
>
>You mentioned putting ferrites on the lines going to the rig. What 
>about the line carrying the +12V power going to the LDG?
>
>How is the connection between the tuner and the antenna (i.e. 
>shorted twinlead) and the ground radials configured? Do you have a 
>short piece of coax running to the feedpoint where the radials and 
>the shorted twinlead come together? Is there a current balun (i.e. 
>RF choke) on that coax to help keep the coax outer conductor and 
>tuner chassis from becoming part of the radial system?
>
>73, Mike W4EF................
>
>On 1/23/2019 8:57 PM, Mark Schoonover wrote:
>>Good evening,
>>
>>Hoping the collective of SCCC can give me some assistance. I'm looking
>>at participating in the ARRL 160M contest this weekend. The antenna is
>>a 33' of shorted ladder line with a 40M full wave loop at the top
>>antenna. I put down as many radials as I could, some are close to 1/4
>>wave on 160 but most are lucky to be 1/4 on 40.
>>
>>I have an IC-7600 attached to a LDG 1000proII tuner. I can get a good
>>match all across 160M <1.3:1 on the tuner's built-in SWR meter but the
>>meter on the rig is >3:1 and power folds back. I have the tuner right
>>next to the rig with RG-213 from DXE between the two. There's 1" braid
>>from tuner->rig->ground rod outside. When I take the LDG out of line
>>and use the rig's built-in tuner, I can get 1.4:1 across the band.
>>
>>I initially thought it was RFI getting back into the rig because the
>>antenna is about 5' from the radio desk. I put mix 43 chokes on every
>>cable entering the rig. No luck on that front but it sure did reduce
>>RFI.
>>
>>So any ideas what this could be? I'm scratching my head on this one...
>>
>>Thanks for reading!
>>
>>73! Mark KA6WKE