[AMRadio] open wire line (update)

David Knepper collinsradio at comcast.net
Tue Nov 20 10:55:27 EST 2007

I prefer dowel rod soaked in melted beeswax with a tablespoon of Jack 

Dave, W3ST - W3CRA
Collins Radio Association
Join the largest Collins group in the world
Nets on 7208 at 4:30 EDST every day and
Monday at 3805 at 8 PM EDST

----- Original Message ----- 
From: "Geoff/W5OMR" <ars.w5omr at gmail.com>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Tuesday, November 20, 2007 10:50 AM
Subject: Re: [AMRadio] open wire line (update)

> Due to 'operator error' (must be a short circuit between the mic and the 
> operators chair) I find I don't need to do anything to the current antenna 
> situation, save for making sure the SWR bridge (out of the transmitter, 
> into the tuner, out to balanced feed-line) is connected to the proper coax 
> connection on the tuner (DOH!)
> (grab bow, slot an arrow, assume good balanced stance, aim, shoot arrow 
> into foot)  DOH!
> Yeah... I screwed up and connected the SWR bridge output to an antenna 
> connection on the tuner, instead of the RF input connector (DOH!)
> (me and my dumb-ass!  I wish hard living didn't come so easy to me!)
> Still mysterious as to why the feed line (disconnected from the tuner) and 
> loop showed to be 'open', instead of closed, like it did this morning. 
> (*shrug*)
> So, I'll continue with plans to build the open wire feed-line.. I'm just 
> not as pressed for time now as I was, prior to reviving the antenna 
> system.
> I'm gonna go with either 1/8" or 1/16" plexi-glass, drill holes 1/4" in 
> from the 4 1/2 plexi strips and 'v' a notch with a triangle-shaped small 
> wood file.
> The wire I'll be using is 14ga stranded, insulated copper clad steel.
> Due to the size of the coax hole (through the wall, near the ceiling of 
> the shack) that the 450 ohm ladder line barely fits through now, I'll 
> leave about 5' feet of that on the tuner, and connect the 4" wide 
> feed-line outside.  There'll be a slight impedance bump, but nothing 
> drastic or critical below 30Mc (I never get above 7.3Mc, anyway)
> Thanks to everyone for the suggestions.
> I'd like to extend an invitation to all AM'ers;  look for activity on the 
> bands late Wednesday evening.  I'll be either at the bottom of 3700 (up to 
> 3.725 - wherever there's a clear hole) or up around 3.880~90 operating 
> while my traditional turkey smoking process is taking place, over night. 
> If there's too many in any one particular round table, find a clear 
> frequency and call CQ AM!   With a cold front draping across the nation 
> and dropping the temperatures in Texas (at least) down some 30+ degrees, 
> long distance conditions -should- be favorable.
> -- 
> Driving your AM Rig without a scope, is like driving your car at night, 
> without headlights. (K4KYV)
> 73 = Best Regards,
> -Geoff/W5OMR
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