Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: adjusting "rf gain" for digital modes  (Read 7641 times)
AK4YA
Member

Posts: 106




Ignore
« on: September 24, 2013, 05:44:00 PM »

I thought I remembered reading something somewhere about when setting up for RF gain, on the lower bands you want to not only disable the preamp, but also to start cranking back the rf gain setting until you see something happen on your S meter (possibly until it stops bobbing around or gets to zero or 1, I cant quite remember)

If I am recalling this correctly, what are the reasons for this, and does anyone remember any sources for the info?  Im racking my brain and my firefox browsing history but I can figure it out.
Logged
VA7CPC
Member

Posts: 2387




Ignore
« Reply #1 on: September 24, 2013, 09:50:20 PM »

I'll let you hunt down a Youtube video -- by either Elecraft or TenTec -- that illustrates the effect of reducing "RF Gain" on a noisy band.  It's quite audible.

The "RF Gain" control -- on most rigs -- actually controls the gain of both the RF preamp (if it's turned on) and all  the IF stages.  The lower it is set, the lower the gain of those stages, and the less distortion they have on strong signals.

I don't know a "rule".   Try this:

. . . Turn it down until the waterfall goes quiet,
. . . and then bring it up until you get best-possible-copy on the signal you're decoding.   

.                 Charles
Logged
K5TED
Member

Posts: 730




Ignore
« Reply #2 on: September 25, 2013, 06:31:00 PM »

sometimes it helps to disable AGC and turn RF Gain down til success, or turn on ATT. This depends on the radio and how it reacts to no AGC.

AGC can work against you in some situations.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!