Topband: experimenting with inverted L

[Herb Schoenbohm]

Jimmy,  Think of it this way...if the feed point resistance of your 
antenna is 12ohms, "a low VSWR across the band", and fed with a 50 ohm 
transmission line, you have the equivalent of putting a 40 ohm resistor 
from your antenna connection to ground.  This is all wasted power except 
for a few percent that is radiated skyward.


73,

Herb Schoenbohm, KV4FZ
>> The radiation resistance of your antenna is 12 ohms.
>>
>> The 1.5:1 VSWR tells us the base resistance is either 33 or 75 ohms. The
>> ground loss resistance is either 21 or 63 ohms. The radiation efficiency is
>> either 36 or 16 percent.
>>
>> The low VSWR over the band (1.8 to 2 MHz?) points to the base resistance
>> being 75 ohms.
>>
>> Dave WX7G
>> On Nov 30, 2011 1:28 PM, "james soto"<kp2bh at yahoo.com>   wrote:
>>
>>> Hello friends,I am experimenting with an inverted L for 160. the antenna
>>> is about 132 ft long with about 45 to 50 ft vertical and the rest
>>> horizontal.i have about 4 radials connected direct to the antenna and one
>>> wire connecting to other radials that use to belong to another vertical
>>> antenna not in use now. at this time i have work south ,central and north
>>> america but i have not work any europeans as yet. the wsr is pretty ok 1.5
>>> across the band . i disconnect the ground from the antenna and i don see
>>> any difference in swr at all. my question is do leaving the ground wire
>>> disconnected from the ground rod improve the reception? any ideas are
>>> wellcome.
>>>
>>> ps i also have a 1/2 wave dipole for 160 at 60 ft high and running in all
>>> kind of shapes ( no space for long antennas) and my reception is better
>>> with the inverted L.
>>>
>>> thanks and 73's
>>>
>>> de kp2bh   /   kp2dx  jimmy
>>> _______________________________________________
>>>