Topband: Any way to check isolation transformer for FCP

[Guido Tedeschi]

It sounds strange, because to have 45,6 uH with 20 turns the Al should 
be 1140.
With T300A-2 Amidon data (Al = 228), with 20 turns you should have 9,12 
uH (103 ohm of Xl at 1,8 MHz).
73 de Guido, ik2bcp

P.S. Guy, please, answer to mailing list, not privately to Andy, because 
the answer could interest many people.


Il 17/01/2016 17:24, Andrejs Pankins ha scritto:
> William,
>
> Thanks for idea. Are you absolutely right - 5uH is too small for 160m.
>
> Looks like I have a wrong toroid. After playing with amidon toroid
> calculator, I found that 20 turns on T300 will give around 5uH (like mine),
> T300A-2 will give 45.6uH
>
> Regards,
> Andy - YL2QN
>
>
> On Sun, Jan 17, 2016 at 1:52 AM, William Shanney <wshanney at verizon.net>
> wrote:
>
>> 5.7 uH sounds too low for 160M, I’d want ten times that to keep the
>> winding impedance >>50 ohms.
>>
>> Bill, W6QR
>>> On Jan 16, 2016, at 3:44 PM, Andrejs Pankins <yl2qn.andy at gmail.com>
>> wrote:
>>> Hello,
>>>
>>> Need your help. For a long time can't get working FCP for my Inverted L.
>>>
>>> I'm looking for some way to check quality of my homemade isolation
>>> transformer. I'm connect primary to 50 Ohm dummy load and secondary to
>>> Antenna Analyzer. Get reading @1850 Ra=28 Ohm and Rx=34 Ohm. Rx is raised
>>> with frequency. Inductance for primary and secondary is 5.7uH.
>> Capacitance
>>> between primary and secondary is 140 pF.
>>>
>>> These reading looks normal or somthing wrong ? I'm expected 1:1 impedance
>>> transformation without additional Rx.
>>>
>>> Thanks a lot in advance for your help.
>>>
>>> Regards,
>>> Andy - YL2QN
>>> _________________
>>> Topband Reflector Archives - http://www.contesting.com/_topband
>>
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