[Elecraft] OT: question re: antenna/rig swtich

[Erwin Haynes]

I had the very set-up you are considering building - also using the 4 position Alpha Delta switch. I am now converting back to a modified manual set-up.

Why? the Alpha Delta switch developed a fault -- if you open it up you will find that the mechanism is a thin strip of metal which is pressed to make contact with each respective contact of the 4 positions as you move the knob into the next detent.

It seems the metal strip was mounted by the manufacturer "not centered", so that after only after a short period of usage (2 months after installing a new unit) the contact made to the 2 positions on one side of the switch were poor or even intermittent.

It cost me shipping my K-3 back to Aptos both ways and repair costs - and Elecraft was very nice to me on repair costs, even though this was clearly my fault.

So, as a matter of QTH operating philosophy, I have now purchased a MFJ coax patch panel, have labeled all inlets and outlets of the panel and each piece of coax in my QTH on both ends -- and have designed and made copies of a check list which I use each time I re-configure. Perhaps overboard -- but it was an expensive lesson learned.

FWIW.

Regards,
 Erwin
KI4TBD
Canton, GA, USA
"Join the DARC side! Deutscher Amateur Radio Club!" 

Greg Buhyoff wrote:
> Group,
>
> This is off topic and I would deeply appreciate any responses to be
> sent to me off list.  I am posting here because I respect the
> knowledge and experience of the people who are members of this
> reflector.
>
> This may sound stupid but I have not had experience with this before,
> so I ask before I do something stupid.
>
> I use an external antenna switch mounted on the outside wall of my
> house to switch in one of six antennas and have a single coax line
> coming into the radio room.  I now have four separate radio stations,
> 2 K3s and two other radios, all set up differently for different types
> and modes of operation.  All have amps in line that can be used when
> needed -- one a KW and the others 750w output.  Currently I manually
> attach the output coax for the station I want to use to the coax lead
> coming into the house from the external switch.  A pain.
>
> I want to be able to simply use a manual switch to select the station
> that would connect to the external antenna switch coax lead into the
> radio room.  I would then use the manual antenna switch to select the
> station and the remote controller to select the antenna.  I was
> looking at the Alpha Delta manual switch with four switched ports and
> a common and then would connect the common to the coax lead coming
> from the external antenna switch (DX Engineering) and then each output
> coax from each of four stations to the four ports on the Alpha Delta
> and then could switch stations via the Alpha Delta manual switch (all
> ports not selected go to ground) and, obviously, then select my
> antennas as I have been doing using my remote antenna switch.
>
> Again, this sounds stupid, but I have not had to do this before and
> always used manual "antenna" switches to simply select antennas.  My
> question is this:
>
> Given the Alpha Delta manual switch has  >60dB port isolation -- is
> this isolation good enough that I can use the this manual switch to
> select stations even though each of the  stations has the capability
> delivering up to 1 KW output?  I don't want to blow out the front ends
> of the radios connected to this manual switch.
>
> I appreciate any answers that can be sent on to me.  I know this
> sounds stupid, but I have been a ham since 1958 and simply have not
> had or needed to do this.  I now have four great stations that I
> carefully put together as part of a "plan" when I retired and I don't
> want to do something stupid at this point.  I have done plenty of
> stupid things in the past and more will happen, but I thought I could
> simply ask a question here with hopes someone can allay my fears of
> using such a switching setup or educate me in those things I don't
> understand or did not think of.
>
> Thanks so very much and 73,
> Greg K2UM
>  
>
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