[TenTec] Orion and RFI

[Ken & Linda Burrough]

Hi All

This is not being written to say "My way is the only way", it is being
written to hopefully make people think about their station set up.  I will
use the Question and Answer  approach in this posting.  I will ask some
questions about station set up and then give my way of doing it.  This is
what works for me and it may not work for you.

Question One.

How is the House wiring to the Radio Room?

Answer One.

I have two 120VAC lines straight to the breaker box.  They are 12-2 with
ground.  My amplifier uses 240VAC, the cable is 10-3 again straight to the
breaker box.  My house is an 1920's farm house.  It was not wired until 1938
and then it had the knob and tube wiring.  I have rewired the whole house
using breaker box's and all grounded wiring.

Question Two.

What kind of station grounding is installed?

Answer Two.

I use the "Grounding Buss".  The buss is Hard Copper 3/4 inch plumbing pipe.
Each piece of radio equipment is grounded to the buss using copper braid.
The buss has a very heavy braid running to a feed through. Out side the
house I use two short pieces of very large stranded copper wire in parallel,
I never did find out what the gauge is, to my ground rod.  The ground rod is
also the grounding for the house power meter.

Question Three.

How is the 13.8VDC supplied to the station equipment?

Answer Three.

I use an Astron RS-35M power supply.  I also use the MFJ 1118 Power Strip.
MFJ has rf by-passed this power strip.  I also use the grounding lug on the
1118 for grounding to my ground buss.


Question Four.

How is the forward power and swr checked?

Answer Four.

In most all new equipment there is an built in power/swr meter.  I have in
line at any given time three or four power/swr meters.  I DO NOT use any of
them.  If I did I would find I have three or four different reading.  I use
the Autek WM1 SWR & Wattmeter.  The WM1 in placed before the input of my TT
238A antenna tuner.  I have one swr/wattmeter to monitor and know if
something changes in my antenna system.

Question Five.

What kind of antennas do you have and where are they placed around the
house?

Answer Five.

I am on oxygen 24 hours a day and that fact limits my Antenna Farm.  I also
have 3.5 acres of land around my house.  I use GAP Antennas.  My Challenger
has been up and running for 11 years now and the Titan has been in use six
years.  The Challenger is 75 feet away from the Radio Room and the Titan is
127 feet away from the radio room.  I have found over the years in this
hobby if I keep the antennas as far away from the house as I can there will
be less, even no RFI, experienced.  Most antennas use some kind of trap,
matching unit, line isolator or balum.  With the amplifier running at 1kw or
more these traps and other things items placed in the antennas system by the
manufacturer can and will get warm or hot and fail.  This failure can cause
rf on your audio, damage to the antenna system or even your amplifier or
transceiver.  This is why I use the Autek WM1 meter, I can see the change
when it happens.  I did learn the hard way on this one, in Pratt, Kansas in
1985 I built an 40/80 meter trap dipole.  The 80 meter part was cut for the
CW band, one night I heard some friends in the 75 meter phone band and as
every one knows, you have to run at least 1kw to be heard.  The swr was too
high for the balum and bang, my SB-220 output was cut by one forth and the
balum melted down.  Yes I had to buy two new 3-500's for the SB-220 and now
I only use Bencher balums.

I could go on with this but as it is some of you have hit the delete button.
Again this is MY WAY of doing things, I do not except any one else to do it
this way, I only want people to think.

Ken/w8keb (ex ne0c )
Flushing, Ohio