[AMRadio] Ranger II Problem ? Need Help..

Jim candela jcandela at prodigy.net
Tue Apr 11 22:38:12 EDT 2006


    I don't have a Ranger, and never did. Other ranger experts out there
have flooded you with a bunch of good ideas, with maybe one important
exception. When you monitor yourself with a receiver, you often hear hum
when the transmitter is hum free. This is because of ground loops in the
particular set up. It can sometimes be a challenge to get everything right
to where the receiver is not overloaded, the signal is high enough to get
good audio detection, and there are no ground loops to give you the
impression of transmitting hum on your carrier. A scope looking at the RF
output is also a good instrument to use to track these kinds of problems
down. Keep in mind that a scope with a 3-prong power cord will tie whatever
your probe gnd clip is attached to, and tie that back to the power company

    I personally like to use 3 prong power cords on my rigs, and equipment,
BUT I prefer to make that a 60 hz ground, and then attach a braid to each
rig where all the braids attach to a common point where another big wire
goes over to a good RF ground such as a radial system, rods, water pipes,
1960 Cadillac bumper, etc. You can pop a few clamp on ferrite beads over the
power cords to discourage common mode RF from going down the power cords. I
sometimes take a power strip apart, and add a ferrite bar inside where the
hot-neutral-ground wires are wound together over the bar as a common mode
choke. This discourages the RF from using your home wiring as an antenna.

    When I experience hum in the receiver audio, it is usually when I skip
the ground straps, 3 prong cords, ferrite beads, and use a wooden bench. I
always love it then when I pop off a PL-259 while standing on a chair fully
extended, bare feet, other hand on another rig. As soon as that PL-259 comes
off, my body feels like flesh on the electric chair sizzling away while I
lose my balance, fall, scream, and in general make my XYL pester me about my

Good luck with that Ranger!

Jim Candela

-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net]On Behalf Of Mark McDougal
Sent: Tuesday, April 11, 2006 8:12 AM
To: AMRadio at mailman.qth.net
Subject: [AMRadio] Ranger II Problem ? Need Help..

Hello All,
    First; I'm a newbie when it comes to working on tube gear so be gentle..
I have a Ranger II that's developed a problem and I really don't know where
to start looking. The problem is a very loud hum, seems like 60 Hz, heard in
my receiver, that comes from the ranger.. The transmitter tunes up fine, and
modulation is O.K. It isn't there when the transmitter is zeroed into the
receiver, just when I remove the zero.. Completely wipes out the receiver..
I use the same cables, coax, mic, etc.. on another setup and it works fine,
so I've at least eliminated that.. Sounds like a capacitor not working??
anyone experience this before..Where do I start??

Thanks in advance
Mark <K4YN>
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