Where did you connect the analyzer? You want it as close as possible to the
feed point, with as little length of coax jumper as possible. Even a 6 ft
jumper can skew the results, been there done that....
Sent from my iPad
> On Aug 21, 2019, at 12:36 PM, Jeff Blaine <KeepWalking188@ac0c.com> wrote:
>
> An inverted L without radials is a random length wire and the measurements
> are of no meaning until there is a ground system to make up the other half of
> the antenna.
>
> But to Wes point, the 259 and big 160m antennas is a recipe for going nuts.
> You don't even need a high powered BC station - even a low powered station a
> pretty far distance away can cause the 259 to give results in error. A VNA
> or something like the Rig Expert are FAR more robust in this application.
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
>
>> On 8/21/19 12:04 AM, Wes wrote:
>> How many high-powered BC stations do you have around?
>>
>> Wes N7WS
>>
>>> On 8/21/2019 8:55 AM, N4ZR wrote:
>>> I just put up an inverted L, with a vertical length of about 60 feet, and a
>>> total of 135 feet. It is fed through 16 turns of RG-400 on a ferrite core
>>> at the base. There are, as yet, no radials.
>>>
>>> Because I was impatient to see what was going on, I grounded the shield to
>>> a single copper-plated ground rod and connected my MFJ259B. I expected a
>>> high R value, and I got one - 112-122 ohms. But surprisingly (to me),
>>> lowest SWR was at 2.070 MHz, and X remained at zero over quite a wide range
>>> - all the way down to about 1.7 MHz.
>>>
>>> Is this all to be expected? I plan to put down at least minimum radials in
>>> the next few days, and would expect the R value to drop as I do so. Am I
>>> off-base?
>>>
>>
>> _________________
>> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|