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K2 KPA100 LP filter question

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lstavenhagen

K2 KPA100 LP filter question

Hi all,

I was looking through the schematic for the KPA100 and it looks like the LP filters in the amp remain in the RF path during receive. Is this the case? If so do they provide extra LP filtering on RX?

Just sitting here with my finger poised over "add to cart" on the KPA100 kit and was just wondering about that.

Thanks es 73,
LS

Don Wilhelm-4

Re: K2 KPA100 LP filter question

LS,

Yes, the KPA100 low pass filter for the selected band is in the circuit
at all times if the KPA100 is connected to the K2. The KPA100 circuits
required to change bands, etc are powered from the base K2 through the
ribbon cable (the 12CTRL line).
The KPA100 T/R switch circuits are bypassed when operating low power,
but the LPF and wattmeter are in-line.

73,
Don W3FPR

lstavenhagen wrote:

> Hi all,
>
> I was looking through the schematic for the KPA100 and it looks like the LP
> filters in the amp remain in the RF path during receive. Is this the case?
> If so do they provide extra LP filtering on RX?
>
> Just sitting here with my finger poised over "add to cart" on the KPA100 kit
> and was just wondering about that.
>
> Thanks es 73,
> LS
>
>

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lstavenhagen

Re: K2 KPA100 LP filter question

Ok thanks Don.

BTW, am I correct in observing that only the RF cable to J1, the power cable to J4, the audio cable and the ribbon cable to the control panel are the only connections of the KPA100 to the K2? I.e. does the RS-232 interface go in through the ribbon cable?

Looks like it's an easy affair to swap lids and turn it back into a normal 10W K2 with just these connectors?

Tnx es 73,
LS

Don Wilhelm-4

Re: K2 KPA100 LP filter question

LS,
There are no RS-232 signals on the ribbon cable. TXD and RXD are at
CMOS levels through the ribbon cable and the conversion to RS-232 levels
is done on the KPA100 board.
BTW - the AUX I/O connector on the KPA100 (and the KIO2) is just what it
says - it is NOT an RS-232 connector although it does contain 3 RS-232
level signals - TXD, RXD and Signal Ground. The remaining lines are K2
dedicated and are used for communicating with external Elecraft
equipment such as the KPA100, XV transverters, and the KRC2.
Plugging a standard PC computer serial cable into this AUX I/O connector
can damage the K2 - build and use only the cable specified in the KPA100
(or KIO2) manual.

73,
Don W3FPR

lstavenhagen wrote:

> Ok thanks Don.
>
> BTW, am I correct in observing that only the RF cable to J1, the power cable
> to J4, the audio cable and the ribbon cable to the control panel are the
> only connections of the KPA100 to the K2? I.e. does the RS-232 interface go
> in through the ribbon cable?
>
> Looks like it's an easy affair to swap lids and turn it back into a normal
> 10W K2 with just these connectors?
>
> Tnx es 73,
> LS
>
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