| |
HB9ABX > TECH 19.07.06 16:41l 39 Lines 1212 Bytes #999 (360) @ WW
BID : J2NN5WHB9EAS
Read: DG9VH DL1LCA DK2ZA DL8FBH GUEST OE7FMI
Subj: clean digital modes HF
Path: DB0FHN<DB0RGB<OE5XBL<DB0PV<OE7XLR<OE9XPI<HB9EAS
Sent: 060719/1435z @:HB9EAS.CHE.EU [Basel JN37TM] DP6.00 $:J2NN5WHB9EAS
From: HB9ABX @ HB9EAS.CHE.EU (Felix)
To: TECH @ WW
Clean digital modes on HF:
Many stations are transmitting with distorted modulation
on HF digital mode, caused by rf feedback or
ground loops.
To prevent this, I have a detailed text with diagrams
on my home page.
Now I made an important update to this. Here follows
the update:
- A bridge G1 to G2 is only to inserted, if there is no
other ground connection between transceiver (TCVR)
and Pactor controller.
If there exist any other ground connection, then G1 - G2
has to remain open. (Check with ohm meter).
- The ground of the line Mic may not be connected to any
other ground in the box, otherwise ground loops are generated
which produce hum and noise! If you use a plug for this line,
make sure that the ground of the plug is isolated from the box
and from other grounds.
And:
If you use Auxiliary input to transceiver:
--------------------------------------------------------
Make sure that the microphone is not active while you transmit
with the AUX input.
Listen with a control receiver that MIC is not heared while you
transmit in digital mode.
(This happens to many stations - and they are not aware of ...)
73s
Felix HB9ABX
Read previous mail | Read next mail
| |
