[Boatanchors] NC-125 Problem

[Al Parker]

Hi Joe,
	Images, twice the IF freq., the higher one being correct in your case, 
the lower one the image.  Common problem on rcvrs of that vintage and 
design. (but see below) That's why they went to double conversion, with 
a high first RF to make the image signal much farther away from the 
correct one, even when using single conversion on the lower bands.  It's 
made more difficult for the listener when the freq. span is so great, as 
your 1.5 - 4.4 mc.
	Be sure the Ant. & RF coils ares peaked on the proper signal.  Other 
than that there's not much that can be done in the rcvr but use of an 
antenna tuner adjusted carefully for the end of the band you're using, 
would give you better selectivity at RF, and make the image signal weaker.
	Another thought, the low band oscillator should be (usually is) above 
the signal freq., yours is below, as the weaker signal shows up below 
the stronger.  Maybe it's aligned wrong on that band.  The higher bands 
usually have the osc. freq. below the signal, and give images like you 
describe.
	I expect you'd find the problem much more bothersome on 10 meters 
when/if it's open.
73,

Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 8/26/2012 9:04 AM, Joe Connor wrote:
> I have an interesting problem with an NC-125 that I need help with. I picked this set up at a hamfest a few years ago and it looks like it saw a lot of repairs and tinkering over the years.
>
> The problem is on Band C (1.5-4.4 mhz). I get stations in two places. For example, tuning up from 3.3 to 4.0, I get CHU and the 80m ham band where they should be. However, I also get them from 2.4 to 3.1 mhz, which is a difference of about twice the 455 khz IF. The signals in both places are of about equal strength, although the overall sensitivity of this band is less than it should be. I don't have this issue on the other bands.
>
> Any ideas of what's wrong and how to repair it?
>
> As always, thank you for your help.
>
>
>                                Joe Connor
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