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: What should PSK31 look like in DM780 on Xmit?  (Read 1297 times)
NI3S
Member

Posts: 67




Ignore
« on: February 27, 2010, 06:43:02 PM »

I have been 'listening' and copying PSK for a few days now.  Netbook connected to my TS-140 through a PIEXX interface and homemade cables.  I can transmit, but I am not sure if things are adjusted properly to produce the best signal.  While I do see a distinct 'red trace' in the middle of my signal I' not sure if I am splattering all over as it seems wider than it should be.
Logged
KC3EF
Member

Posts: 69




Ignore
« Reply #1 on: February 27, 2010, 06:58:58 PM »

Generally if you have no ALC showing on your radio you will not be over driving on PSK.  This will vary somewhat by radio.  The best check is to ask another station to check you signal.
Logged
G0GQK
Member

Posts: 634




Ignore
« Reply #2 on: March 04, 2010, 02:32:07 PM »

The red trace always appears when you transmit but this is not an indication of the quality of your transmitted signal. Check that there is no ALC showing, that your processor is off, and using only 25/30 watts your transmission will be good. As the previous correspondent suggested, ask your contact if the signal is OK.

G0GQK
Logged
EI7IS
Member

Posts: 1


WWW

Ignore
« Reply #3 on: March 05, 2010, 04:47:42 AM »

Another way of ensuring that your PSK signal is not overdriven is to set the power output on the rig higher than the actual output.

For example, on the FT897 there is a power setting, if this is set to say, 30W.  Then use the volume of the sound card to adjust the output using a power meter to measure the actual RF output.  If this is below the rig setting (in this case 30W) then chances are, you're putting out a clean signal.

That said, of course also look at the other replies - all good advice!

Vy 73 and Good DX de Mark, EI7IS ..._._
Logged
KG6MZS
Member

Posts: 476




Ignore
« Reply #4 on: March 05, 2010, 06:03:40 AM »

KC3EF said:

>>>Generally if you have no ALC showing on your radio you will not be over driving on PSK. This will vary somewhat by radio. The best check is to ask another station to check you signal.<<<

I would go one step further and recommend that you ask several stations over the course of transmitting on several different bands.  Short of having an IMD meter like:

http://kk7uq.com/html/imdmeter.html

it is difficult to know for sure if you are actually over-driving the radio.  As everybody has said here their suggestions are "generally speaking."  There are exceptions.  For instance my Elecraft K3 actually wants to see 3-4 bars of ALC because of the way Elecraft meters ALC.  With most rigs *any* ALC registering is not good.  In some rigs no ALC registering can *still* mean you are over-driving the radio.

Additionally the problem with any given signal report is that distortion can occur anywhere in the the signal chain - including on the RX end.  You may have a good strong clean signal that introduces distortion on the receiving station's radio.  It might not even be due to the fact that you are using a lot of power - it just might be that your antenna is efficient and propagation is providing a solid path to the wonky receiver.

Short of the above IMD meter, checking with a number of stations and making on-air adjustments is probably the best way to get a feel for how your signal is getting out into the waterfall.  Due diligence is appreciated!

HTH

73 de Eric, KG6MZS
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!