A Mini Module I would love to see (AC0LP)

[Jobst Vandrey]

A small board to insert 12 volts DC on the Coax at the shack and a similar board to pick it up at the antenna end to run relays or power remote tuners without impacting the RF carried on the coax.  I really do not want to run a second set of cables just for this purpose.  It would be great if it was configured with some more or less standard DPDT relay positions (optional of course) that could be populated as needed by the user to meet various switching needs.

MFJ does offer such a beast (4116 and 4117 without the relays) - but I admit to some significant uncertainty in the quality of the design and the of the components used in the manufacturing.

Jobst Vandrey
AC0LP


 
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[Alan Bloom]

Many years ago I built a remote antenna switch that allowed feeding up
to 4 antennas from the same feedline.  The feedline also was used for
the control signal, so no additional wires were needed.

It was a very simple circuit.  The switch box at the top of the tower
contained 5 coax connectors, two DPDT relays, two diodes, an RF choke
and a couple capacitors.  The control box in the shack contained 2 coax
connectors, a 60-Hz power transformer, a 4-position switch, an RF choke,
two diodes and a couple capacitors.

The schematic is at http://www.cds1.net/~n1al/ham/ant_switch.GIF

The electrolytic capacitors in the switch box may not be needed,
depending on the relays.  I believe I used 0.1 uF for the coupling and
bypass capacitors something like 22 or 47 uH for the RF chokes.  (A
smaller choke might be required for VHF.)  The transformer was chosen to
provide the correct relay voltage.  You may need to add resistors in
series with the relay coils to fine-tune the voltage.

Al N1AL


On Fri, 2010-12-17 at 07:48 -0800, Jobst Vandrey wrote:

> A small board to insert 12 volts DC on the Coax at the shack and a similar board to pick it up at the antenna end to run relays or power remote tuners without impacting the RF carried on the coax.  I really do not want to run a second set of cables just for this purpose.  It would be great if it was configured with some more or less standard DPDT relay positions (optional of course) that could be populated as needed by the user to meet various switching needs.
>
> MFJ does offer such a beast (4116 and 4117 without the relays) - but I admit to some significant uncertainty in the quality of the design and the of the components used in the manufacturing.
>
> Jobst Vandrey
> AC0LP
>
>
>  
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[Kurt Pawlikowski]

Hi,

     DX engineering has several commercial products:

     http://www.dxengineering.com/Sections.asp?ID=33&DeptID=17#Top

     I also saw in a QST (sorry, don't remember which: I've been
re-reading QST's from the last few years) an IP driven RF controlled
remote. I suspect a lot more expensive, but it had a range of several
hundred feet.

     Regards,

     kurtt

     Kurt Pawlikowski, AKA WB9FMC
     The Pinrod Corporation
     [hidden email]
     [phone]
     http://pinrod.com

On 12/17/2010 14:50, Alan Bloom wrote:

> Many years ago I built a remote antenna switch that allowed feeding up
> to 4 antennas from the same feedline.  The feedline also was used for
> the control signal, so no additional wires were needed.
>
> It was a very simple circuit.  The switch box at the top of the tower
> contained 5 coax connectors, two DPDT relays, two diodes, an RF choke
> and a couple capacitors.  The control box in the shack contained 2 coax
> connectors, a 60-Hz power transformer, a 4-position switch, an RF choke,
> two diodes and a couple capacitors.
>
> The schematic is at http://www.cds1.net/~n1al/ham/ant_switch.GIF
>
> The electrolytic capacitors in the switch box may not be needed,
> depending on the relays.  I believe I used 0.1 uF for the coupling and
> bypass capacitors something like 22 or 47 uH for the RF chokes.  (A
> smaller choke might be required for VHF.)  The transformer was chosen to
> provide the correct relay voltage.  You may need to add resistors in
> series with the relay coils to fine-tune the voltage.
>
> Al N1AL
>
>
> On Fri, 2010-12-17 at 07:48 -0800, Jobst Vandrey wrote:
>> A small board to insert 12 volts DC on the Coax at the shack and a similar board to pick it up at the antenna end to run relays or power remote tuners without impacting the RF carried on the coax.  I really do not want to run a second set of cables just for this purpose.  It would be great if it was configured with some more or less standard DPDT relay positions (optional of course) that could be populated as needed by the user to meet various switching needs.
>>
>> MFJ does offer such a beast (4116 and 4117 without the relays) - but I admit to some significant uncertainty in the quality of the design and the of the components used in the manufacturing.
>>
>> Jobst Vandrey
>> AC0LP
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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[Craig Smith]

A few days ago AC0LP suggested a mini-module kit for the purpose of sharing
the coax with 12V control line(s) - an enhanced bias T, essentially.  N1AL
followed up with a nifty design he had used for selecting up to four remote
antennas without running additional conductors - Thanks Alan!

It seems that there would be a significant demand for this type of thing for
those folks who purchase the upcoming KAT500 remote tuner (me, for
instance).  I'd like to suggest integrating this type of capability into the
tuner/controller design. The hardware could be optional so that only those
who use it need to pay for it - perhaps a second remote box connected to the
tuner box?  

Basic functionality:  Ability to select a number (4 or 6?) of remote
antennas from the K3 (or in-shack KAT500 controller if one is used).
Ideally the user should have ability to do some mapping of the selection vs.
band, etc.  Only connection to the remote tuner should be the single coax.
Also provide a 12V signal at the remote box for each antenna as it is
selected so that the user can power another relay or two for additional
configuration if needed.  For example, to common the conductors of an
open-wire line feeding a doublet so that it becomes a Marconi vertical.  All
features should work with either the KPA500 or a barefoot K3.

Other suggestions?

2011 could be a fun year  ;>)

73  Craig  AC0DS


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