[R-390] Antenna question

Thu, 18 Jul 2002 20:39:11 -0500

Where I was, being a dry land sailor, we had rhombics oriented every 30
degrees feeding walls of multicouplers (CU-168s) feeding racks of
patch-panels, feeding lots of R-390As, and one lonely SP-600. Forgot
where. Had a memory wipe when I left. Are those black helicopters I
hear? AAARRRGGGHHHHHH..............

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of John Kolb
Sent: Thursday, July 18, 2002 8:19 PM
To: Thomas W Leiper
Cc: [email protected]
Subject: Re: [R-390] Antenna question

On Thu, 18 Jul 2002, Thomas W Leiper wrote:

> On Thu, 18 Jul 2002 08:20:26 -0500 "Scott, Barry (Clyde B)"
> <[email protected]> writes:
> > What is/was the recommended "standard" antenna and feedline for the
> > R390A?
>
> input, do the Navy mod, which grounds one side of the balanced
> input (making it unbalanced) and feeding the other side out the
> unbalanced bulkhead connector. That gives you an unbalanced
> 75 ohm system which not only allows you to use cheap TV coax
> like RG-59 or RG-11, but also just happens to be the impedance
> at the feedpoint of a resonant half wave dipole.

Yep, that's how we fed them on the Navy ships I was on - a right
angle connector which plugged into the twinax connector, shorted
one side to gnd and output the other to the center pin of a type
C connector.

We mostly fed them with 35 foot vertical whips, through long runs
of coax, but also had a couple of long wire available, also connected
with long coax.

John

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