HR-10 thread...

[Bill Coleman]

On 9/18/02 9:57 AM, Gerald C. Lemay at w1id at FCGNETWORKS.NET wrote:

>You can indeed narrow the "nose" of the filter but you can't really
>improve "skirt" selectivity due to the fact there are only 2 crystals
>comprising the filter. Some years ago I got a junker HR-10, took out the
>filter transformer and crystals and put it in another HR-10. Other than the
>fact insertion loss was greater than a stock HR-10, selectivity was then
>pretty decent for most CW operation and some SSB.

I did a similar experiment some years ago. I had two HR-10Bs (one was my
brothers), and put two identical crystals in the IF. My theory was that
it would have an extremely narrow filter.

Unfortunately, it didn't work. I couldn't get the IF amplifier to stop
oscillating, no matter how I re-tuned the IF transformer.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901

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