a couple of Dumb questions,
WAG = QST states all bands, does this include 30 meters?
my propagation program implies this is the only
band workable for a West coast little pistol.
Scout Jamboree-on-the-air = DX Bulletin claims info is in
QST, I must be going blind. Are they working
special event stations, or some kind of contest and
be looking for QSOs and Multipliers?
73, alan N2ALE/6
Internet: ames@nebula.decnet.lockheed.com
>From Jim Reisert AD1C 15-Oct-1993 1220 <reisert@wrksys.enet.dec.com> Fri Oct
>15 17:16:05 1993
From: Jim Reisert AD1C 15-Oct-1993 1220 <reisert@wrksys.enet.dec.com> (Jim
Reisert AD1C 15-Oct-1993 1220)
Subject: Amplifier maintainence tips from KM1H
Message-ID: <9310151616.AA12094@us1rmc.bb.dec.com>
Carl, KM1H posted this message on our PacketCluster recently. It has some
excellent tips, and he has agreed to share it with the net.
73 - Jim AD1C
Now is the time....not during the contest! In the power supply do a visual
check for leaky electrolytics, overheated or cracked resistors and pitted
relay contacts.
In the RF section, carefully remove the tubes. With ceramic tubes, vacuum
dirt from the fins. With glass tubes, clean with Windex, including the
chimneys. Radiation thru the glass is an important part of the cooling
process....nicotine film is a great tube killer. Vacuum the blower/fan
blades; if build-up severe, remove it with a small brush and household spray
cleaner.....blow dry before replacing tubes. Check plate choke for burn
spots, particularly if been used on WARC bands. ALPHA 77 series also
notorious for blowing choke when "pushed" on 160M...a simple cure exists.
Check parasitic chokes...apply moderate pressure and try to break the 2W
resistor; you can't break a good one. Check ALL solder joints in plate
circuit RF path from plate cap to coax connector. Use needle nose pliers to
flex the connection. What may appear to be a perfect connection may have
been crystalized by RF.....I've also found rosin joints in 20+ year old
amplifiers!!
Finally check the output SO-239; there are far too many garbage brands
installed that eventually break down. Replace with a real amphenol phenolic
or Teflon.
The above suggestions are basic preventative maintainence that apply to all
amps. Certain models have other needs/quirks/etc. Last but not least check
all those coax cable connections to switch/relay panels. Any that get
excessively warm after a few minutes of full power should be repaired.
Enjoy the contest and good luck......Carl
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