[TenTec] Antenna is up, but the coupler doesn't like 160 meters

Mike Bryce prosolar at sssnet.com
Sat Oct 12 11:59:09 EDT 2013


bob and the gang,

inserted the 259 and with the 1:1 balun.

resonate freq is 2.487 or there abouts

so the antenna as it sits is too short.

I'll re-check the length with my harbor freight made in china 300 foot tape and see what each leg is (length wise)


Mike Bryce, WB8VGE
 the heathkit shop
SunLight energy systems
J e e p
o|||||||o






On Oct 12, 2013, at 10:42 AM, Bob McGraw - K4TAX wrote:

> The extra / external cap is used across the capacitor bank, starting at position #4 and #5.  Both on the Low and High Z sides.  I find the text is incorrect, the schematic is correct.  Yes a .01 is way too much C by a factor of 10x.
> 
> If you have a means to do so, what is the natural resonant frequency of the antenna?  I use my MFJ-259 as a grid dip meter effect to find the resonant frequency.  I'm not speaking of some frequency where the SWR is 1:1 or such.
> 
> I take a different approach to antennas.  I first start with a resonant antenna at the desired frequency, then adjust the height of the antenna to attain the desired feed point impedance.  I saw Jim Brown, K9YC mentioned this in his earlier post as he used different coax impedance lines dependant on the height of the antenna.  I am not one to "prune" the length of the antenna for some SWR value.  Now in cases I know we can't get the antenna at different heights specially as we get to 160M and to some extent 80M.  In these cases, the typical height above ground does bring the center Z to 20 to 30 ohms.  Nothing wrong with this.  With low loss coax or a balanced feed, just let the tuner deal with it.  That's what it is supposed to do.  I find having a resonant wire is more effective and easier to effect a good match.
> 
> 73
> Bob, K4TAX
> 
> 
> 
> 
> 



More information about the TenTec mailing list