[NLRS] COAX RELAYS

[Gerald]

On Mon, 2006-01-23 at 11:20 -0800, christenson at charter.net wrote:
> 
> Anyone use a common feed line then split it for the various bands at the tower and shack?
> 
> I am thinking of upgrading to hard line without busting the budget. Bands will be 2/222/432/1296 at SOLP levels.
> 
> Comments welcome and requested.
> 
> 73'
> 
> Kris KC0REO

That can work. For lower bands there are commercial products in the form
of relays. Relays are probably the lowest loss, but there might be a set
of splitters with reasonable loss. I've been thinking about them for
decades but not produced any. Running 3/4" CATV hardline that has cost
nothing but connectors has lead me away from trying the build really
good splitters. Yes, its 75 ohm, but it has worked fine for me on all
bands up through 1296.

The cat's meow would probably be a motor driven rotary coax switch and
there have been some military multiple position types out.

Back in the late 50s my dad and I tried using a B&W coax switch up top
the tower with a ratchet wheel drive and a 120 volt solenoid. It worked
fine on the ground but with the added wire length, it tended to bang the
solenoid with so much extra velocity (once the voltage was raised to get
the solenoid to move at all) that the switch detent let the switch roll
past the desired single step in an unpredictable manner. Once we got it
settled on the preferred band we didn't try moving it again. And the
next time the tower was down (it wasn't climbable), the rotary switch
was removed and multiple coax runs were made. In retrospect, a worm gear
motor with a crank to pull the ratchet precisely one notch with
controlled speed should have worked better. Or a box full of relays.
-- 
73, Jerry, K0CQ
Dr. Gerald N. Johnson, electrical engineer
All content copyright, Dr. Gerald N. Johnson