schematic for HD 1481

[Bob And Bettina Groh]

That is exactly my recollection of the HD 1481.  It was developed and
kitted when I was working at Heathkit (1977-1981) by Jim Smiley if my
memory serves me right.  You jogged my memory and I'm pretty darn
certain you've got it dead on. The RF switch wafer was the same one used
in the manual coax selector.  The 'pulsing' action of the Ledex was
built into it if I remember rightly.

Another way to switch a rotary switch is with a small dc motor (geared
way down).  Works nicely as I used that concept in several antenna
couplers I designed at Harris Corp (RF Communications Div, Rochester,
NY) back in the early 70's.

Bob Groh, WA2CKY

Multi-Volti wrote:

>I don't remember if Heath had one model with multiple relays or not, but
>someone does. The Heath one I was familiar with used a Ledex rotary solenoid
>(which are pretty expensive nowadays) which had a switch section also. The
>shaft also rotated an external ceramic switch wafer with matching indexing
>(angle of position).
>
>The integral switch wafer (non-ceramic) was wired so that the Ledex solenoid
>would rotate repeatedly until it reached the position that 'matched' the
>desired one. There might have been a contact that momentarily interrupted
>with each actuation, causing the repeated pulsation. I am not very
>mechanically inclined, and attempting to figure it out was too tedious for
>me. It reminded me of a resolver position indicator arrangement in that it
>was unstable until it reached the position that opened the wiring to the
>ratchet device. I keep adding details as I remember them...sorry. I think it
>only went in one direction, so that if you reversed one position, the
>solenoid had to actuate repeatedly to cycle thru all the positions to get to
>the one you wanted.
>
>Maybe someone else can confirm this - I didn't dream this up, really! It was
>pretty cool to watch with the cover off, but noisy mechanically as well as
>electrically. I recall it making a pretty bad racket resonating bolted to a
>tower.
>
>Murray
>
>
>----- Original Message -----
>From: Kenneth Laine Ketner <ketner at ARISBEASSOCIATES.COM>
>To: <HEATH at LISTSERV.TEMPE.GOV>
>Sent: Thursday, July 17, 2003 8:18 PM
>Subject: schematic for HD 1481
>
>
>Greetings greenies:
>
>I am doing some antenna experimenting, and need a function like the
>Heathkit HD 1481 remote coax switch. Does anyone know of a schematic for
>it on the web. Didn't find one on BAMA.
>
>Lacking a schematic, maybe someone can describe the mode of operation. I
>understand it switches a remote box on the tower by sending  12 VDC
>pulses along the coax (no extra wires needed for switching). One coax
>cable up the tower, and 4 antennas switchable at the tower top box. This
>is the kind of function I need. Just what are the details of how it does
>that?
>
>--
>
>Ken Ketner
>ARS KA5ELD (Extra Class)
>  Personal Webpage: http://www.wyttynys.net
>  Office Webpage: http://www.pragmaticism.net
>Email:
> home: ketner at arisbeassociates.com
> office: kenneth.ketner at ttu.edu
>
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