K3 KFL3B-FM Change?

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K3 KFL3B-FM Change?

Joe Subich, W4TV

In the past day or two I have noticed a change on the K3 order page.
The KFL3B-FM was previously listed as a 7-pole filter at $99.00.  
It is now listed as an 8-pole filter at $120.00.

Is this an "error correction" or a change in the specifications?  If
this is a change in the specifications, does this indicate data is  
available for the "new" version and does this represent an improvement
in skirt selectivity and ultimate rejection such that the KFL3B-FM
can be used successfully for both AM/ESSB transmit and receive?  

How does this change effect those who have previously placed orders
that included the KFL3B-FM?

73,

   ... Joe, W4TV
 

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Re: K3 KFL3B-FM Change?

Eric Swartz - WA6HHQ
Administrator
Hi Joe,

We've decided to go with a 8-Pole FM filter manufactured for us by
Inrad, instead of the lower performance discrete 7 pole xtal filter we
were planning on designing and using. The 8 pole filter has an excellent
shape factor and better ultimate rejection than the 7 pole discrete xtal
filter. I'll post more data on it next week when I have time.

All orders received before the change will be honored at their $79 price
and will get the 8 pole filter. All new orders will be at the new price.
So if your order confirmation says $79, that's what you will pay. (at
our loss) :-)

73, Eric   WA6HHQ

Joe Subich, W4TV wrote:
> In the past day or two I have noticed a change on the K3 order page.
> The KFL3B-FM was previously listed as a 7-pole filter at $99.00.  
> It is now listed as an 8-pole filter at $120.00.
> ...
>
> How does this change effect those who have previously placed orders
> that included the KFL3B-FM?
>
>  
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RE: K3 KFL3B-FM Change?

Joe Subich, W4TV

Eric,

> We've decided to go with a 8-Pole FM filter manufactured for us
> by Inrad, instead of the lower performance discrete 7 pole xtal
> filter we were planning on designing and using. The 8 pole filter
> has an excellent shape factor and better ultimate rejection than
> the 7 pole discrete xtal filter.

Thank you.  I look forward to the data - particularly information
on suitability for use with AM/ESSB in both transmit and receive.

I can't see where either AM or ESSB are exactly suitable for weak
signal operation which would imply some degree of AGC and make
90 to 100 dB of image rejection sufficient for most AM/ESSB use.

> All orders received before the change will be honored at
> their $79 price and will get the 8 pole filter.

I think the most recent price was $99 ... but it's appreciated.  

73,

   ... Joe, W4TV
 



> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Eric
> Swartz - WA6HHQ, Elecraft
> Sent: Friday, October 26, 2007 4:02 PM
> To: Joe Subich, W4TV
> Cc: [hidden email]
> Subject: Re: [Elecraft] K3 KFL3B-FM Change?
>
>
> Hi Joe,
>
> We've decided to go with a 8-Pole FM filter manufactured for us by
> Inrad, instead of the lower performance discrete 7 pole xtal
> filter we
> were planning on designing and using. The 8 pole filter has
> an excellent
> shape factor and better ultimate rejection than the 7 pole
> discrete xtal
> filter. I'll post more data on it next week when I have time.
>
> All orders received before the change will be honored at
> their $79 price
> and will get the 8 pole filter. All new orders will be at the
> new price.
> So if your order confirmation says $79, that's what you will pay. (at
> our loss) :-)
>
> 73, Eric   WA6HHQ
>
> Joe Subich, W4TV wrote:
> > In the past day or two I have noticed a change on the K3
> order page.
> > The KFL3B-FM was previously listed as a 7-pole filter at $99.00.  
> > It is now listed as an 8-pole filter at $120.00.
> > ...
> >
> > How does this change effect those who have previously placed orders
> > that included the KFL3B-FM?

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Re: K3 KFL3B-FM Change?

Eric Swartz - WA6HHQ
Administrator
I stand corrected! :-)  Thanks for the info.

Those that paid the old price of "$99.00" for the 7 pole FM filter will
still get the 8 pole FM filter for that price. (not $79) New orders will
be at $120.

73, Eric


Joe Subich, W4TV wrote:
> I think the most recent price was $99 ... but it's appreciated.  
>
>  
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RE: K3 KFL3B-FM Change?

Brett gazdzinski-2
In reply to this post by Joe Subich, W4TV
 
Personally, I cant hear anything above about 4000 Hz, that
would be 8Kc bandwidth on AM.

The R390a had 4Kc (slightly too narrow) to 8Kc then 16Kc.
4, 6 and 8 Kc are the most useful for me, as that gives 2, 3, and 4Kc
audio output if tuned dead on carrier.
In the telephone world, equipment allows out to 4Kc.
That was considered optimal for intelligibility vs bandwidth.

For swl use, 16Kc is not unreasonable for people with good ears, that gives
8Kc
audio out..

I hope the K3 can be got to 4Kc in the AM mode tuned dead on the carrier.
others might like it even higher, but I can hear it.

Brett
N2DTS


 


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Re: K3 KFL3B-FM Change?

David Woolley (E.L)

> In the telephone world, equipment allows out to 4Kc.
> That was considered optimal for intelligibility vs bandwidth.
>
The telephone network bandwidth is 3.1kHz (300 to 3400Hz).  4kHz was the
analogue bearer channel separation, and allows for realistic shape
factors on the channel filters.  On digital signals, the 8kHz sampling
rate allows the use of realistic anti-aliasing filters when the audio
bandwidth is 3.1kHz.


> For swl use, 16Kc is not unreasonable for people with good ears, that gives
> 8Kc

The channel spacing for SW broadcast stations is 5kHz,  although I
suspect they are are allowed to overlap each other.  I'm sure there are
standards for this, but I suspect a well maintained transmitter is
limited to a similar audio bandwidth as the telephone system, or less. I
would think that one would normally expect to be received with a filter
that was well down the skirt at 10kHz, so as to suppress the adjacent
carriers.  Propaganda stations and commercial ones in a poorly regulated
environment might well transmit more bandwidth.  (Medium and long wave
transmissions use 9kHz channel spacing.)

--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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