[TowerTalk] VA6AM triplexer and BPFs
k6ll.dave at gmail.com
Mon Apr 23 23:29:00 EDT 2018
I just installed the very same system at W7WW's last Friday. He
also got the 100 cfm fan on the 10 Meter BPF because his antenna
has a 2:1 SWR at 28.0, and he is a RTTY guy. He also has the
system installed in the shack, right behind the operating table.
The three 50 cfm fans are not loud at all. They are set to come
on whenever he turns on one of the AL-1500 Amplifiers. With the
noise generated by the AL-1500 blowers, and with headphones on,
the three 50 cfm fans are not audible.
The 100 cfm fan is a totally different story. It sounds like a
Hoover vacuum cleaner, and overrides all of the other noises in
the shack, including the window AC unit. We have it wired to the
10 meter position of the Six-Pak selector switch so that fan
comes on only when 10 is selected. You can ask Pavel what the
thinks, but I would really try to get by with the 50 cfm fan. I
think I saw a blurb where K3LR says the 100 cfm was too loud, and
reduced the voltage to 10-11 volts. Now that I think of it,
W7WW's Astron is set to 14.5 volts, so maybe we will also try
reducing the fan voltage with a few diodes or a resistor.
Dave Hachadorian, K6LL
From: Bill via TowerTalk
Sent: Monday, April 23, 2018 2:05 PM
To: TOWERTALK at contesting.com
Subject: [TowerTalk] VA6AM triplexer and BPFs
Thanks to all who responded to my questions on triplexers and
To the guys using the high power VA6AM...
I'll be solely SO2R, never M2. So only one signal on the air at
a time....legal limit (really) The smaller fans are what I'm
getting on the BPFs except for 10 M. On 10 I'm getting the
bigger one which I believe is 100CFM. I know the smaller fans
are pretty quiet, but the larger one is pretty noisy.
Any thought s as to the necessity of the bigger fan for 10 and
how noisy are the fans? The whole set up will be under the
operating desk in the kneehole.
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