K3 with SDR-IQ and external antenna for SDR-IQ?

[Bob KD7YZ]

Howdy K3' people:

Here's another one I am trying to solve. What if I want to receive down
at 17.2KHz  sometimes ... or certainly below 4 or 500KHz, the base of
the K3? Well,, that connection to the IF, was handy and safe, but now I
need external antenna.

Also, it is safest of when the SDR-IQ is not to the IF  that we switch
the SDR-IQ input to maybe a 50 ohm dummy during xmit cycle of K3.

Anyone have this worked out? What equipment re you using and what
connection from K3 does the switching.

I have sequencer's for my 6m EME pre-amp ... just wondering what anyone
else does with the K3?

Actually, I need to know this anyway since the EME stuff was
driven/switched by my former rig, the FT-950 and I haven't figured out
how to switch the sequencer on K3 xmit anyway.





--
73
KD7YZ Bob

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[Don Wilhelm-4]

Bob,

To receive VLF you will need a VLF converter.  The IF connection on the
K3 is only an output, so the converter will connect to one of the
antenna inputs to the K3.  If it is to be receive only, you could
connect to the RX antenna input or to the ANT1 or ANT2 connections of
the KAT3, or to the RX port of the KXV3.

If the external device is to transmit as well as receive, you can
connect it to one of the KAT3 antenna jacks, or if it is capable of 1 mW
IF transmit levels, connect it to the same IF connectors as used for the
VHF/UHF transverters.

73,
Don W3FPR

On 12/16/2012 6:31 PM, KD7YZ Bob wrote:

> Howdy K3' people:
>
> Here's another one I am trying to solve. What if I want to receive down
> at 17.2KHz  sometimes ... or certainly below 4 or 500KHz, the base of
> the K3? Well,, that connection to the IF, was handy and safe, but now I
> need external antenna.
>
> Also, it is safest of when the SDR-IQ is not to the IF  that we switch
> the SDR-IQ input to maybe a 50 ohm dummy during xmit cycle of K3.
>
> Anyone have this worked out? What equipment re you using and what
> connection from K3 does the switching.
>
> I have sequencer's for my 6m EME pre-amp ... just wondering what anyone
> else does with the K3?
>
> Actually, I need to know this anyway since the EME stuff was
> driven/switched by my former rig, the FT-950 and I haven't figured out
> how to switch the sequencer on K3 xmit anyway.
>
>
>
>
>

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[Bob KD7YZ]

Don tapped out:


> To receive VLF you will need a VLF converter.
Well,  that would be neat if Elecraft made one ... would integrate
nicely. Then, since all I want to do is RX, I'd be isolated and not
worry about frying the SDR-IQ.

However, that's not the case, so I have to run an antenna straight into
the SDR-IQ, and I have already done this twice. The first time, I was
handily listening down at 17KHz with just the antenna to the SDR-IQ.

Second time I was also xmit on the K3 and tuning the 450 ladder line.
The SDR took a hit, I fear.

Thus, I want to switch the SDR-IQ's antenna input OFF whatever existing
external antenna she has WHEN I hit xmit on the K3. Call it a
precaution. Won't have anything to do with xmit on the K3 nor Rx. Just
the fact I want to externally close a relay that puts the SDR-IQ into
50-ohm lad when K3 xmit.

This is essentially what we do with some high-end Pre-amps for EME.

I was hoping somebody in the list had already solved the mechanics.


>   The IF connection on the
> K3 is only an output, so the converter will connect to one of the
> antenna inputs to the K3.  If it is to be receive only, you could
> connect to the RX antenna input or to the ANT1 or ANT2 connections of
> the KAT3, or to the RX port of the KXV3.

> If the external device is to transmit as well as receive, you can
> connect it to one of the KAT3 antenna jacks, or if it is capable of 1 mW
> IF transmit levels, connect it to the same IF connectors as used for the
> VHF/UHF transverters.

> 73,
> Don W3FPR

> On 12/16/2012 6:31 PM, KD7YZ Bob wrote:
>> Howdy K3' people:
>>
>> Here's another one I am trying to solve. What if I want to receive down
>> at 17.2KHz  sometimes ... or certainly below 4 or 500KHz, the base of
>> the K3? Well,, that connection to the IF, was handy and safe, but now I
>> need external antenna.
>>
>> Also, it is safest of when the SDR-IQ is not to the IF  that we switch
>> the SDR-IQ input to maybe a 50 ohm dummy during xmit cycle of K3.
>>
>> Anyone have this worked out? What equipment re you using and what
>> connection from K3 does the switching.
>>
>> I have sequencer's for my 6m EME pre-amp ... just wondering what anyone
>> else does with the K3?
>>
>> Actually, I need to know this anyway since the EME stuff was
>> driven/switched by my former rig, the FT-950 and I haven't figured out
>> how to switch the sequencer on K3 xmit anyway.
>>
>>
>>
>>
>>

--
73
KD7YZ Bob

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[Edward R Cole]

KD7YZ Bob:

Not difficult to do with the K3.  Connect to the KEY OUT connector
with wiring to the ground side of a 12v coax relay with a 50-ohm term
on the NO coax connection.  Connect the SDR-IQ to the relay common
coax connection and antenna to the NC coax connection.  The K3 will
cause the coax relay to switch the SDR-IQ into the load when the K3 transmits.

The SDR-IQ has to be on a separate antenna from what the K3 is
connected, to ensure no RF goes to the SDR-IQ.

If you already are using the KEY OUT for controlling something else
then a NPN transistor is needed to isolate the relay coil from the
other device.  The NPN will invert the logic so you may need another
transistor stage to maintain the same logic.  Alternately you can
make an logic isolator with two diodes such that current from the
relay does not flow to the other device but only thru the K3 KEY
ckt.  (sounds more complicated than it is).

73, Ed - KL7UW

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[K7MDL]

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