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KXR3 3db Splitter

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nl7g

KXR3 3db Splitter

I am on the waiting list for a K3 and have ordered the KXR3.
In reading the manual for both the Sub Receiver and the K3
an alarm bell starting ringing in my ears when I read.
Not Quoted: Basically saying
1. A 3db splitter is used when the KXR3 is installed. Turn off
the Sub Receiver and the Main RX sensitivity is restored
to normal.
2. Also stating this 3db splitter (effectively a pad??) is in use
for both antenna ports, but is not used when the RX only
antenna port is used.
In audio terms isnt 3db half of the power?? How much
sensitivity is compromised by installing the 2nd receiver to
the main receiver?
I am trying to work some of you guys in the noise floor.
Do I need to turn off the sub receiver every time I am
trying to work a barely audible station??
IF this is a real problem, I have time to cancel my KXR3.
Any practical experience by those who have received
there sub receiver would be greatly appreciated.
Thanks Mike NL7G

Bill W4ZV

Re: KXR3 3db Splitter

nl7g wrote

I am on the waiting list for a K3 and have ordered the KXR3.
In reading the manual for both the Sub Receiver and the K3
an alarm bell starting ringing in my ears when I read.
Not Quoted: Basically saying
1. A 3db splitter is used when the KXR3 is installed. Turn off
the Sub Receiver and the Main RX sensitivity is restored
to normal.
2. Also stating this 3db splitter (effectively a pad??) is in use
for both antenna ports, but is not used when the RX only
antenna port is used.

In audio terms isnt 3db half of the power?? How much
sensitivity is compromised by installing the 2nd receiver to
the main receiver?

I am trying to work some of you guys in the noise floor.
Do I need to turn off the sub receiver every time I am
trying to work a barely audible station??
IF this is a real problem, I have time to cancel my KXR3.
Any practical experience by those who have received
their sub receiver would be greatly appreciated.

Thanks Mike NL7G

3 dB should not be a major a problem except possibly on 10/6m, where you might need a preamp. The atmospheric noise floor on the lower bands is well above the noise floor of the K3 and you'll probably not miss 3 dB. For example on 160m I normally operate with the 10 dB ATTenuator on. On 10m my "preamp" is a 22 dBi gain antenna so I doubt 3 dB is an issue for me (no sunspots is an issue however!)

73, Bill

Eric Swartz - WA6HHQ

Re: KXR3 3db Splitter

Administrator

All radios that have an independent sub receiver have an identical
splitter to allow two receivers to use the same receive antenna path. It
is rare that you will ever notice the very small difference in signal
level, as Bill mentions.

Also, when the sub RX is not turned on, (or when it is receiving on an
independent antenna) the signal is -not- being split and hence their is
no loss.

73, Eric

Bill W4ZV wrote:

>
> 3 dB should not be a major a problem except possibly on 10/6m, where you
> might need a preamp. The atmospheric noise floor on the lower bands is well
> above the noise floor of the K3 and you'll probably not miss 3 dB. For
> example on 160m I normally operate with the 10 dB ATTenuator on. On 10m my
> "preamp" is a 22 dBi gain antenna so I doubt 3 dB is an issue for me (no
> sunspots is an issue however!)
>
> 73, Bill
>

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nl7g

Re: KXR3 3db Splitter

Thank you for the response. Let me push this one step further.

It was my impression in other receivers that only affects the 2nd receiver,
but that is not my worry or concern. Are you saying the splitter is
only used if I am using a single antenna?? That if I use a second
antenna on antenna port 2 or the aux port this is not a issue??
I did not think the manual said that, but if that is true, I can live
with that. I think it would be a much better if the main receriver's
sensitifity was left alone however. I could fully understand 2nd
receiver impairment much like the standard radio's VFO A/B setup.

Thank you for the quick response.

Mike NL7G

All radios that have an independent sub receiver have an identical
splitter to allow two receivers to use the same receive antenna path. It
is rare that you will ever notice the very small difference in signal
level, as Bill mentions.

Also, when the sub RX is not turned on, (or when it is receiving on an
independent antenna) the signal is -not- being split and hence their is
no loss.

73, Eric

Bill W4ZV wrote:
>
> 3 dB should not be a major a problem except possibly on 10/6m, where you
> might need a preamp. The atmospheric noise floor on the lower bands is well
> above the noise floor of the K3 and you'll probably not miss 3 dB. For
> example on 160m I normally operate with the 10 dB ATTenuator on. On 10m my
> "preamp" is a 22 dBi gain antenna so I doubt 3 dB is an issue for me (no
> sunspots is an issue however!)
>
> 73, Bill
>
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Bill W4ZV

Re: KXR3 3db Splitter

nl7g wrote

Are you saying the splitter is
only used if I am using a single antenna?? That if I use a second
antenna on antenna port 2 or the aux port this is not a issue??

Correct. You have 3 dB splitting loss **ONLY** when the same antenna is shared (i.e. split). Normally in Diversity you have one antenna on Main and another on Sub, so there is no splitting loss in that case.

73, Bill

nl7g

RE: KXR3 3db Splitter

Thank you Bill. The advantages of the 2nd receiver outweigh the drawbacks
in this case. The manual said only with the aux port this was not an
issue. Or perhaps in my panic attack my brain only saw SPLITTER.

Thanks Mike NL7G

Date: Fri, 12 Dec 2008 14:06:57 -0800
From: [hidden email]
To: [hidden email]
Subject: Re: KXR3 3db Splitter

nl7g wrote:

Are you saying the splitter is
only used if I am using a single antenna?? That if I use a second
antenna on antenna port 2 or the aux port this is not a issue??

This email is a reply to your post @ http://n2.nabble.com/KXR3-3db-Splitter-tp1647375p1649842.html
You can reply by email or by visting the link above.

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N5GE

Re: KXR3 3db Splitter

In reply to this post by Eric Swartz - WA6HHQ

On Fri, 12 Dec 2008 12:43:43 -0800, you wrote:

>All radios that have an independent sub receiver have an identical
>splitter to allow two receivers to use the same receive antenna path. It
>is rare that you will ever notice the very small difference in signal
>level, as Bill mentions.
>
>Also, when the sub RX is not turned on, (or when it is receiving on an
>independent antenna) the signal is -not- being split and hence their is
>no loss.
>
>73, Eric

[snip]

Thanks, Eric, for introducing me to true diversity RX. Don't know how I did
without it!

Tom Hinson Childers, N5GE

K3 #806, XV144, XV432
Mini-Modules

http://www.eQSL.cc/Member.cfm?N5GE
http://www.n5ge.com
http://www.swotrc.net

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Amateur Radio Operator N5GE