Topband: Diversity-capable transceivers

[Cecil Acuff]

Yup...wish I could find an RX-366 to upgrade my OII...

Production was short...

Cecil
K5DL

Sent using recycled electrons.

> On Nov 30, 2015, at 7:14 PM, Barry N1EU <barry.n1eu at gmail.com> wrote:
> 
> Thanks Tom.  FWIW, Ten-Tec offered an upgraded subreceiver (RX366) for the
> last year or two of Orion2 production (very similar to main rx, adapted
> from their Eagle xcvr).  At the same time, the Orion firmware was updated
> to offer a front panel feature to manually adjust the RX366 oscillator
> frequency in 0.1Hz steps to precisely zero beat again the main rx.  It
> works well and maintains the phase relationship over time as well as across
> the bands.
> 
> 73, Barry N1EU
> 
> 
>> On Tue, Dec 1, 2015 at 12:19 AM, Tom W8JI <w8ji at w8ji.com> wrote:
>> 
>> Barry,
>> 
>> It is more than just second receiver quality. For maximum diversity
>> effect, the receivers must use a common time base for both channels. They
>> do not have to be phase synced (unless blended into mono), a person's brain
>> will learn around that. The channels should not drift phase when on a given
>> frequency, and if phase changes with tuning, it should be very gradual.
>> 
>> This can be checked by running a common oscillator or carrier signal into
>> both channels and listening in mono. Another test is observing background
>> noise with a single antenna common to both channels. Listening in mono can
>> be as simple as laying the headphones on the desk. There should be no beat
>> warble or no fading and peaking on a carrier, and when the band is swept on
>> noise any change in apparent audio level with frequency change should be
>> very gradual.  Ideally there should be no changes at all.
>> 
>> My R4C's, because I used one receiver's oscillators to run both channels,
>> were perfect. The K3's I have are imperfect, they have a gradual phase
>> change between channels with frequency.
>> 
>> My FT1000D was terrible, as was the Orion I had. They gave some diversity
>> effect, but were so far unsynced they did not give the deep noise digging
>> the K3 or R4C system would.
>> 
>> If you never use a system that is phase locked, you might not realize the
>> difference. The channel audio phase relationship has to be stable without
>> drift to get the real enhancement.
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