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[TenTec] Narrow FM

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Subject: [TenTec] Narrow FM
From: w5yr@swbell.net (George T. Baker)
Date: Mon, 04 Oct 1999 20:18:19 -0500
Just to add to the historical note aspect, Jerry:

In 1947 I ran NBFM on ten meters using a Sonar XE-10 NBFM adapter. I
worked the world on FM running an 807 at about 50 watts input and a
4-element yagi at about 20 ft. All this also near Dallas at Bonham, Texas
- about 65 miles northeast of Dallas.

72/73, George        AMA 98452          R/C since 1964                 
Amateur Radio W5YR, in the 54th year and it just keeps getting better!  
AutoPOWER Systems, Fairview, TX (30 mi NE Dallas)  Collin County

"Dr. Gerald N. Johnson, P.E." wrote:
> NBFM probably hasn't been used on ham bands in 30 years though the
> whisperers on 2m "wide" fm are that narrow. Truly NARROW band FM has the
> same band width as AM, about 6 KHz, no second order modulation products.
> But copied exalted carrier on an SSB receiver it has a great sound. In
> the mid 60's around Dallas, Texas, several of us used that mode on the
> bottom of 2m. It sounded super, better than SSB, in my 75S3B. I planned
> to, but never did, build a NBFM receive adapter. It can be slope
> detected in an AM receiver (not with crystal or mechanical filters) but
> that's not the best way to do it.
> Mathematically, this truly NARROW fm has the same spectrum as AM, just
> the carrier is 90° different in phase. There would be few on 40 with AM
> receivers that would understand that blank carrier, though those using
> SSB receivers would copy just fine. And the neighbor's TV wouldn't
> notice any modulation.
> 73, Jerry, K0CQ

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