[HBR] 50Khz IF Transformer fior new Build

[B. Smith]

Be sure an consult your AM station listings, either local or FCC data 
base for stations. Often some of these AM stations are off the air as 
they are remoted and there "is no one there". TIS does use 1.710 here in 
Chickenland but that is low power unless it is down the street.
BTW crystals below 4 Mcs  are becoming expensive. International prices  
all most triple when ordering below "4 Mcs".  Maybe look for a FT-243 
crystal and  get out the tooth paste.  :-)  I see that AF4J has one 
rock  "advertised" on his site for 1.700, perhaps that would be a candidate.

http://www.af4k.com/FT243crystals1500-1999khz.htm


On 1/14/2014 9:37 AM, Steve wrote:
> AS I began looking at the "as designed" IF freq I find that it is the same
> freq as one of the local high power AM stations  (1600Khz) one other choice
> I have is 1700 and there is a much lower power signal there when I listen
> with my IC756.  It is complety quite between 1700 and 1800, totally dead
> here.  Is this range then my best choice of IF???  Or can I get by with 1700
> with good shielding of the IF???  The station on 1700 is not really very
> strong but I can copy it ok...  What to do??
>
> Steve
>
>   
>
> -----Original Message-----
> From: hbr-bounces at mailman.qth.net [mailto:hbr-bounces at mailman.qth.net] On
> Behalf Of B. Smith
> Sent: Monday, January 13, 2014 11:41 AM
> To: HBR Receiver List
> Subject: Re: [HBR] 50Khz IF Transformer fior new Build
>
> Be sure an choose your oscillator frequency carefully due to possible local
> AM broadcast.
> When using an IF that is different then published you can expect a few
> "birdies" and you will have to change the mixer injection crystal. So you
> may want to do the math first.
> http://k4che.com/HBR/Testing/Progress%20Testing%20pg%201.htm
>
> On 1/13/2014 10:18 AM, Steve wrote:
>> I am in the process of gathering parts and I have been dealing with trying
>> to find IF Transformers.   I have quite a few 265Khz ones that will need
>> modifications, 5 ea  85Khz ones from an ARC 5  and some 50Khz ones
>> from a junker National NC300.  So the big question for me is which
>> sets should I use?  Modifications of the 265 is quite a task, so it
>> seems to come down to using the 85Khz ones whihc there is plenty
>> written about how to do that or use the 50Khz ones from the National.
>> Any reason that I should not use the 50 Khz ones, understanding that I
>> have to make a few changes in the oscillator frequencies...The 50 Khz
>> ones would be easy to use and mount on the chassis.  This the last major
> hurdle for parts that I have.
>>    
>> Steve NU0P
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