[Boatanchors] Fw: HRO Alignment of Plug-In Coilsets

[Olaf Madsen]

 From: "Olaf Madsen" <olaf at carolina.rr.com>
To: <boatanchors-request at mailman.qth.net>
Sent: Tuesday, January 13, 2009 9:05 PM
Subject: HRO Alignment of Plug-In Coilsets


>I am working on an HRO-7,trying to make the alignment on the various 
>plug-in coilsets.----HRO-5,or any of the other HRO's also use these 
>coilsets.
>
> The sensitivity varies greatly over the tuning range,particularly for the 
> General Coverage Ranges (say 3.5 to 7.3 Mc for the ''C'' set )
>
> The procedure for alignment described in the instruction manual allows for 
> adjustment at a HIGH frequency point of the range (7.3Mc for the ''C'' 
> set ) by the trimmers which are accessable at the front of the coilsets 
> from the inside of the receiver.
>
> Any alignment to the LOW frequency end must be made by changing the 
> Inductance of the coils from the back of the coilset---however---there is 
> NO ACCESS to them ,except when the coilset is OUT of the receiver..---the 
> same goes for the Padding trimmers,they cannot be reached while the coil 
> set is plugged in.
>
> In the words of the manual : ''The original alingment was ("is'') 
> accomplished by the use of precision,crystal -controlled test 
> oscillators.---No realignment should be attempted,'' etc etc.
>
> What's  a ''boanchor ham'' to do with a 50 odd year piece of gear that 
> needs some TLC.--What do you say you old  guys from ''National 
> Company''---Any advice ????---or references.
>
> Tnx fr any help --73 de Olaf,KF4TP---
>