Comments on CQHQ: Vertical half-wave aerials for 4m

New URL for this article on summitsbase is http://...

2012-04-29T00:04:37.379+01:00

New URL for this article on summitsbase is http://www.summits.org.uk/tiki-index.php?page=4m+J-pole

The dimensions of the 70Mhz Slim Jim at www.summit...

2009-12-09T10:17:35.839Z

The dimensions of the 70Mhz Slim Jim at www.summitsbase.org.uk/tiki-index.php?page=4m+J-pole
only seems to work for a certain type of 300 ohm ribbon. It certainly does not work for the cable I have here. I suspect it is to do with the carbon content of the black plastic used in the insulator in Mike's design. I have made 10 versions from the grey coated cable I have but could not get any of them to work. It is not really surprising when you model a Slim Jim or J-pole at 4M the gap between the 1/4 stub and vertical section should be about 6 inches and we only have a 1/4 inch gap using 300 ohm ribbon.

Hi - using 300 Ohm ladder line, the correct dimens...

2009-12-08T10:37:40.876Z

Hi - using 300 Ohm ladder line, the correct dimensions for the 70Mhz slim jim can be found at:

www.summitsbase.org.uk/tiki-index.php?page=4m+J-pole

I have made this one and it works perfectly.

I previously tried several designs, all of which failed miserably!

Steve, MW0KST