[HBR] HBR-11 IF xformer critcal coupling?

[WA5VGO]

I wouldn't sweat it at this time. After you get the I.F. wired, put a 100 
KC signal into it and make sure you get a good peak on each transformer and 
then continue on with the receiver construction.

When you finish the receiver, two things should be apparent. First, on 80 
and 40 meters, you should have way too much receiver gain. You should find 
it necessary to back off on the manual gain controls. This is normal. 
Second, the I.F. should begin to regenerate when you approach maximum with 
the manual gain control. If these objective are obtained, you're probably 
okay. If not, then I'd start  slowly decreasing the distance between the 
coils until this condition is obtained.

BTW, when you wind the 80 meter antenna coil, I'd only put 7/8 of a turn on 
the primary winding. I know this sounds ridiculous, but even with the 
coupling this light, you'll still have excessive gain.

73,
Darrell, WA5VGO



At 06:04 PM 3/22/2009 -0500, bignick at execpc.com wrote:


>Hello all,
>
>A question, please ..
>
>I have been following the instructions for modifying the K-Tran
>262 kHz I.F. transformers
>as per the re-work instructions at: http://www.qsl.net/k5bcq/HK/HK.html#SUB
>
>I have modified the first coil by sliding both coils to the ends
>of the coil form.
>It is actually a small distance, perhaps 3/16"
>or so for each coil.
>
>I note that when I route a signal thru the
>modified I.F. coil that there is considerable signal
>loss as
>compared to an unmodified I.F. transformer.
>
>On my remaining two
>coils, I have slid only one of the two I.F. coils to the end of their
>coil forms and much more signal level is maintained.
>
>My
>question is:  How can I tell (or can I tell) when I've got the coils
>under/over/critically
>coupled?
>
>Will I need to wire enough
>of the I.F. circuitry in order to route a signal through the
>transformers when they are correctly loaded?
>
>Thanks!
>
>--Tom Nickel AKA KC9KEP


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