Topband: BDR redux

[John Kaufmann]

Bill Tippett wrote:

>  The new 3uV default [in the Orion] is OK for 10m,
> which has relatively low atmospheric noise, but is still MUCH
> too high for 160 meters.  About the lowest I ever set mine
> on 160 is 20-30 uV, and often much higher.  


I found exactly the same thing during my first extended operating time with the Orion during the recent CQ160 contest.  I realized immediately that the 3uV default AGC threshold value is way too low for a "noisy" band like 160m and it makes the radio sound very unnatural to my ears.  This is precisely what I wrote on this reflector in my recent assessment of the Orion.  People who don't take the time to explore the effects of the threshold setting may never realize what a rather powerful control function it is.  During the CQ160 contest, I generally ran with the threshold between 20 and 30 uV and sometimes higher.  Only when the band was very quiet (mainly during daylight hours of the contest) did I ever drop back towards the default value.

Also I found it helped to add a tiny amount of hang time (.04 seconds) to reduce the perceived AGC pumping in the fast mode.


>  This is why Orion's AGC takes
> some seat time to learn to use properly.  Once learned, it is fairly
> easy to adjust and the AGC action is the best I've seen at keeping
> a wide range of signals at comfortable levels.  

AGC has always been one of my pet peeves in radios.  Of all the radios I've used until now (outside of the Orion), only the IC-781 seems to have gotten it mostly right.  Among other things, the IC-781 has a continuously variable AGC time constant control.  However, TenTec may be onto something with its AGC programmability, and it's both a blessing and a curse.  Some people will say it's too complicated.  It does take time to learn how to extract optimal performance from it. On the other hand, if you never deviate from the default values, you're leaving performance on the table.

73, John W1FV