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Reviews Categories | Receivers: Vintage amateur | Treetop Circuits SB 390 Product detector for R-390A Help

Reviews Summary for Treetop Circuits SB 390 Product detector for R-390A
Reviews: 1 Average rating: 5.0/5 MSRP: $95
Description: Similar to the SB-51, with wide dynamic range and a dual time constant AGC circuit. In AM mode, the adapter is switched out of the circuit entirely, so performance on AM is unchanged
Product is in production.
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You can write your own review of the Treetop Circuits SB 390 Product detector for R-390A .

K1QAR Rating: 5/5 Dec 18, 2013 07:15 Send this review to a friend
excellent piece of engineering  Time owned: more than 12 months
Like the SB-51, this gives modern transceiver sideband performance. Installation is directly onto to the back terminal strip by replacing three screws with standoffs. Three wires are poked into the IF deck and soldered (Poke first, then strip), and two wires replace the AGC jumper on the back terminal strip. The radio can thus easily be returned to original.

As with the SB-51, sideband is tuned just like a modern transceiver, with the bandwidth set at 2Kc just tune for maximum noise, then adjust the BFO for intelligible audio.

For synch AM, I actually find temporary use of the limiter very handy for quickly finding zero beat, since it interacts with the BB-390 to somehow enhance the BFO tone.

In sum, by far the best single accessory/mod I've found for the legendary R-390A

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