[AMRadio] HRO-50

David Knepper collinsradio at comcast.net
Mon Nov 26 18:00:11 EST 2007

 Now that is a technician who knows what he talking about.  Thanks, Carl.

Dave, W3ST - W3CRA

----- Original Message ----- 
From: "jeremy-ca" <km1h at jeremy.mv.com>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Monday, November 26, 2007 5:54 PM
Subject: Re: [AMRadio] HRO-50

> Finally, some one actually read the manual!
> The alignment is actually quite simple once youve been thru it once.
> The way we determined which way to move that wire was to insert a plastic 
> rod with a piece of aluminum glued on one end and powdered iron on the 
> other. Aluminum decreases the inductance and iron increases it.
> Carl
> KM1H
> National Radio 1963-69
> Service Tech, Service Mgr
> Member of NCL-2000 Design Team
> ----- Original Message ----- 
> From: "Larry Will" <lhwill at verizon.net>
> To: "Discussion of AM Radio in the Amateur Service" 
> <amradio at mailman.qth.net>
> Sent: Monday, November 26, 2007 5:38 PM
> Subject: Re: [AMRadio] HRO-50
>> Mike,
>> My book indicates, like many National receivers, on D band a single loop 
>> of wire inside of the coil is bent to add/subtract inductance.  I just 
>> looked at my RF input coil (opened it up) and there is the wire.
>> The wire is accessible through the left rear hole, looking from the top 
>> of the assembly (the side with the contacts).
>> Se page 19 in the HRO50-1 National manual for all the coils.
>> I have seen some cases on some receivers (not an HRO-50) where the range 
>> may not be sufficient.
>> Larry
>> W3LW
>> 11111
>> At 04:03 PM 11/26/2007, you wrote:
>>>What a pain in the scrote. The manual says to adjust the coils for the 
>>>end of the band, (in this case, I'm using coil set D 1.8-4.0M GC 3,5-4.0 
>>>and there aren't any adj. available. I looked in the in each coil set and 
>>>can see the coil but it looks as though it was designed not to be adj. 
>>>I'm hesitant about attempting to adj. them. The only one that has an
>>>adjustment for GC is D-4. It worked well on 160 but it was damn near deaf 
>>>75M. I wanted to make it back to standard but its a real tough go. I 
>>>have left well enough alone. Well, in for a penny, in for a pound.
>>>----- Original Message -----
>>>From: Jim Wilhite
>>>To: Discussion of AM Radio in the Amateur Service
>>>Sent: Monday, November 26, 2007 3:22 PM
>>>Subject: Re: [AMRadio] HRO-50
>>>Fun isn't it Mike.  That is the way.  If there is an easier way, I would
>>>like to see it.
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