[TenTec] ORION headphone clicks - the fix!

[Ulrich Hilsinger]

Hello,


Bob Henderson <bob at cytanet.com.cy> wrote:
> On a noisy band with the clicks in evidence I've had a lot of success in 
> reducing the clicks and sometimes removing them completely by increasing 
> AGC threshold, which I guess prevents the AGC system from trying to ramp 
> the noise up to full output between character elements

In fact, this seems somehow plausible to me. It's probably just the 
price one has to pay for the excellent behaviour the ORION was stated to 
have on weak-signal work and an AGC setting optimized therefor. If you 
want to have a receiver which gives a good audio for weak signals with 
not far less audio power then for loud signals, you have to use a 
sufficient high IF amplification and a low AGC threshold. On the other 
hand, the ORION allows a defined setting of the AGC threshold, thus 
making it possible to adopt the behaviour to the band actually in use. 
It makes no sense to have AGC threshold at -130 dBm if your noise level 
is -120 dBm.
Additionally, if the AGC attac time is not fast enough or the AGC reacts 
not at once when switching back to RX in QSK mode, you'll get an 
"overshooting" AF output until the AGC has attenuated the noise...

I can reproduce the same "problem" (I really never considered it as a 
problem...) on my TS850. At certain speeds and volume levels, I hear 
those clicking noise transients, and if I hang the AGC up to a certain, 
higher value, the clicking disapears. That's just the same.

So, it's really not an ORION problem, it's just a general behaviour..

73,
Ulrich dh0ghu
dh0ghu at dh0ghu.de