[Top] [All Lists]

[AMPS] Readings on Clipperton L

To: <>
Subject: [AMPS] Readings on Clipperton L
From: (David L. Thompson)
Date: Mon, 9 Mar 1998 10:12:57 -0500 (EST)
At 11:36 PM 3/8/98 -0800, you wrote:
>Hi all,
>       I'm geting some funny readings (or so they seem) when I try to transmit
>using my Dentron Clipperton L. I'm using an FT 840 for a transceiver and
>a MFJ 896 Antenna Tuner sits on the other side of the Dentron. When the
>Dentron is turned on, I get 2500v plate and when it's keyed in CW mode,
>I get .666-.750 amps current. But I can't seem to get the MFJ 986 to
>register any more than about 150watts out in CW and 100w out in SSB
>mode, in 40, 20, and 15 mtr bands. What's going on here. Am I doing
>something wrong and if so, what should I be doing?
>Thanks for any help,

I saw the reply from W7CW and never had that problem but did blow the meter
and the resistors that are right on top of the chassis next to the top cover
on 10 meters.  Until that time the amp ran fine.

I traded around and got a second Clipperton and had almost your exact
problem on 40.  I was using a full wave horizontal loop at my IOTA location
(same as before) and notice this Clipperton was funny with regard to the
tuner (also the MFJ 986) on 15.  I drive it with an old IC740 and listening
to the monitor in the receiver the signal sounded hollow on both CW and SSB
whereas on 20 it sounded normal.  The tuner tuned to the exact same spot
but for some reason this amp/tuner combo just had a problem.  During the
ARRL DX test DX sigs were loud as before but no one came back on 40 SSB with
the amp.  I worked several barefoot but none with the amp.  Power was 800
watts tho.  On 15 all I could get was 200 watts and one guy said it sounded
terrible.  Switch to the IC740 barefoot and it sounded OK.

Somehow the amp and the tuner just had a problem...low output and RF
feedback.  I got rid of the amp and used a National NCL2000 with no problems.

I used short leads of RG213 in the shack and used Radio Works top quality
RG8X to the loop with 75 feet of coax.  Ground was to the water pipe and a 6
foot ground rod 7 feet away max.  Loop is just over 300 feet (longer than 80
meters) but loads and works great on all bands 80 to 10 including WARC's.
One guy who fixes amps said it might be a problem in the RF Choke.  Dentron
used what they could get and probably changed mfgs several times.  I found
the PS caps (450V) were a special Mallory order and hard to replace.

The Clipperton worked fine at home on the fixed station antennas.

Dave K4JRB 

FAQ on WWW:     
Administrative requests:

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