Topband
[Top] [All Lists]

Re: Topband: W8JI FT1000MP MKV Click Modification

To: <topband@contesting.com>
Subject: Re: Topband: W8JI FT1000MP MKV Click Modification
From: "Guy Olinger, K2AV" <olinger@bellsouth.net>
Date: Sun, 23 Oct 2005 17:17:04 -0400
List-post: <mailto:topband@contesting.com>
"Keying waveforms for both
the normal "mid-word" rising edge, and the "hard-edge" leading
character are shown. The radio still clicks pretty bad, but only
on the leading characters that follow a word-space (or longer
pause. Mid-word characters don't cause clicks with the mod
in place."

There are some missing details in your description so I don't know 
your exact setup.

If you are listening on another RX and putting the audio to a scope or 
a sound card and a scope program, do NOT use AGC on the listening 
device. Turn it off and reduce the manual gain so that the RX is 
running fixed RF gain.

If you are looking at the output of an amplifier and using ALC to set 
the drive levels, then turn the ALC off. Reduce power manually to get 
proper drive levels. Using ALC with a low drive amp will produce the 
same affect as the AGC in a RX.

If none of the above, remember that the MP uses some number of 
physical relays (vs pin diodes) in the transition from RX to TX.

Use the menu setting 7-4 to introduce a delay of 4 or 5 ms (or more?) 
to delay the onset of CW until after the circuits complete state 
change.

The 7-4 delay is a bucket brigade delay that introduces a constant 
fixed delay between ALL key down and baud RF out (0-30 ms). The entire 
baud sequence is delayed without any "chopping" This is especially 
useful to keep from burning change-over relays and worse in amps and 
elsewhere by applying power from the MP before the state change is 
completed.

Contrary to the manual, (in the regular MP anyway) this works whether 
or not BK-IN is on.

There are some number of relay changes that have to take place before 
RX-TX state change is complete in an MP. Different MP's (by experience 
at NY4A with nearly a dozen) clearly have different intrinsic timings.

You can hear this delay by setting 7-4 to 30, click MONI "on" and use 
a keyer with a sidetone. MONI will let you hear a tone based on MP 
timing going out, whereas the keyer sidetone is synchronous with the 
key input. In the MP with MONI "off" the tone you hear is also synch 
with the key input.

You can also hear this delay by listening in a separate RX vs the MP 
internal sidetone with MONI "off".

The "hang" delay in menu 7-5 is added to the 7-4 delay. On CW 7-5 
serves to keep a slow amp relay closed between bauds and characters so 
it doesn't thrash. I set my 7-5 so at 25 wpm it opens between 
characters, but not between dits.

Set 7-4 for leading edge issues and 7-5 for trailing edge issues.

With my MP and Alpha 76A I have 7-4 at 8 and 7-5 at 0.08.

73, Guy






Scanned for viruses by Blue Coat
http://www.WinProxy.com/
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband

<Prev in Thread] Current Thread [Next in Thread>