[ARC5] Receiver input impedance.

[Geoff]

>
> ----- Original Message ----- 
> From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
> To: <Arc5 at mailman.qth.net>
> Sent: Tuesday, October 30, 2012 12:30 PM
> Subject: [ARC5] Receiver input impedance.
>
>
>> Does anyone have accurate data on the BC-453B receivers'
>> antenna input
>> impedance?
>>
>> I need to build an UN-BAL to match my BC-453B to a 3 foot
>> diameter
>> Stoddart loop which is fed with twin-ax.
>>
>> I have the Stoddart data, but need the other data.
>>
>> My particular BC-453B does not have the loop connections.
>>
>> Can anyone help?
>>
>> Kenneth G. Gordon W7EKB
>
>
>     If you know someone with an RF impedance bridge its
> easy to measure the actual impedance at the antenna input.
> Someone on this list may have the equipment and be within
> reasonable distance. I suppose it could be calculated from
> the values of the input tank but I can't tell you
> specifically how.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com


You can also get a ballpark idea with a couple of toroids.

A single one can be effectively tapped up to a 12:1 ratio and if that keeps 
increasing signal strength to the end then feed it into another and find 
where the maximum signal transfer occurs.