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XVTR IF BAND CAN NOW BE 10 OR 18 MHZ

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todd ruby-2

XVTR IF BAND CAN NOW BE 10 OR 18 MHZ

Not being as technically savvy as many here on the reflector, can someone tell me the benefits and theory behind the differences in using these two IF freqs. in the XVTR?

thanks in advance

todd
WB2ZAB
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wayne burdick

Re: XVTR IF BAND CAN NOW BE 10 OR 18 MHZ

Administrator

There's no particular benefit to an 18-MHz I.F. But 10 MHz can be useful for VLF/LF transverters (e.g., 500 kHz) because very high-stability 10-MHz oscillators (OCO's, or oven-controlled oscillators, etc.) are available at low cost for use as the mixer injection oscillator. This combined with the K3's excellent stability can allow the use of extremely narrowband modes that require very low drift.

73,
Wayne
N6KR

On Feb 5, 2014, at 12:20 PM, todd ruby <[hidden email]> wrote:

> Not being as technically savvy as many here on the reflector, can someone tell me the benefits and theory behind the differences in using these two IF freqs. in the XVTR?
>
> thanks in advance
>
> todd
> WB2ZAB
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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Edward R Cole

Re: XVTR IF BAND CAN NOW BE 10 OR 18 MHZ

In reply to this post by todd ruby-2

Just to expand a big on what Wayne states:

Operation on the upcoming (but not yet established by the FCC) new
600 meter ham band on 472-479 KHz, K3 use is enhanced by this upgrade
in the firmware. It allows operating the K3 on 10.472-10.479 MHz as
the IF input to a transverter which can use a super-stable OCXO or
GPS disciplined oscillator as the 10 MHz LO. Since there will only
be 7-Hz spectrum in the whole ham band only narrow band modes will be
allowed. Stations will need to hold +/- 1-Hz in frequency stability
and accuracy to avoid interfering with each other.

I use a surplus OCXO (Oven Controlled Xtal Oscillator) that I bought
on e-bay for $45. This holds my K3 to 0.01ppm by use of the EXREF
and TCXO-3 options. On 10-MHz band this results in under 1-Hz
drift. Using a transverter that has drift considerably below 1-Hz
permits me to use my K3/10 (w/ KVX3) on this new band.

I am in early design process to make such a transverter with 25w
output and utilizing a 10-MHz OCXO for LO. At this time I'm
considering offering it as a kit. Only 1mw RF level is needed by the
transverter for IF drive. I expect this is six months off in
realizing. It would also be nice if the KX3 was able to work at
10.472-10.500 MHz.

73, Ed - KL7UW
http://www.kl7uw.com/kits.htm

From: Wayne Burdick <[hidden email]>
To: todd ruby <[hidden email]>
Cc: Elecraft Reflector Reflector <[hidden email]>
Subject: Re: [Elecraft] XVTR IF BAND CAN NOW BE 10 OR 18 MHZ
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

There's no particular benefit to an 18-MHz I.F. But 10 MHz can be
useful for VLF/LF transverters (e.g., 500 kHz) because very
high-stability 10-MHz oscillators (OCO's, or oven-controlled
oscillators, etc.) are available at low cost for use as the mixer
injection oscillator. This combined with the K3's excellent stability
can allow the use of extremely narrowband modes that require very low drift.

73,
Wayne
N6KR

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

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wayne burdick

Re: XVTR IF BAND CAN NOW BE 10 OR 18 MHZ

Administrator

Ed,

Your transverter idea sounds like a nice addition to the K3. (Such a transverter could be also used with the KX3. But due to size constraints, of course, the KX3 uses a different synthesizer technology that can't provide 1-Hz stability.)

Wayne
N6KR

On Feb 5, 2014, at 3:59 PM, Edward R Cole <[hidden email]> wrote:

> Just to expand a big on what Wayne states:
>
> Operation on the upcoming (but not yet established by the FCC) new 600 meter ham band on 472-479 KHz, K3 use is enhanced by this upgrade in the firmware. It allows operating the K3 on 10.472-10.479 MHz as the IF input to a transverter which can use a super-stable OCXO or GPS disciplined oscillator as the 10 MHz LO. Since there will only be 7-Hz spectrum in the whole ham band only narrow band modes will be allowed. Stations will need to hold +/- 1-Hz in frequency stability and accuracy to avoid interfering with each other.
>
> I use a surplus OCXO (Oven Controlled Xtal Oscillator) that I bought on e-bay for $45. This holds my K3 to 0.01ppm by use of the EXREF and TCXO-3 options. On 10-MHz band this results in under 1-Hz drift. Using a transverter that has drift considerably below 1-Hz permits me to use my K3/10 (w/ KVX3) on this new band.
>
> I am in early design process to make such a transverter with 25w output and utilizing a 10-MHz OCXO for LO. At this time I'm considering offering it as a kit. Only 1mw RF level is needed by the transverter for IF drive. I expect this is six months off in realizing. It would also be nice if the KX3 was able to work at 10.472-10.500 MHz.
>
> 73, Ed - KL7UW
> http://www.kl7uw.com/kits.htm
>
> From: Wayne Burdick <[hidden email]>
> To: todd ruby <[hidden email]>
> Cc: Elecraft Reflector Reflector <[hidden email]>
> Subject: Re: [Elecraft] XVTR IF BAND CAN NOW BE 10 OR 18 MHZ
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=us-ascii
>
> There's no particular benefit to an 18-MHz I.F. But 10 MHz can be useful for VLF/LF transverters (e.g., 500 kHz) because very high-stability 10-MHz oscillators (OCO's, or oven-controlled oscillators, etc.) are available at low cost for use as the mixer injection oscillator. This combined with the K3's excellent stability can allow the use of extremely narrowband modes that require very low drift.
>
> 73,
> Wayne
> N6KR
>
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> "Kits made by KL7UW"
> Dubus Mag business:
> [hidden email]
>
> ______________________________________________________________
> 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

Jim AB3CV

Re: XVTR IF BAND CAN NOW BE 10 OR 18 MHZ

In reply to this post by Edward R Cole

I don't remember if I ordered the TXCO-1 option for my SN 1210 K3. Is it
obvious if I open the unit? What would I look for?

Is the TXCO option necessary if the External reference is used?

Thanks

jim ab3cv
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