[600MRG] Fwd: K3 transverter operation

[Pat Bunn]

Sent from my iPhone

Begin forwarded message:

> From: Pat Bunn <pbunn at matrixei.com>
> Date: May 4, 2014, 7:13:52 PM EDT
> To: Eric NO3M <no3m at no3m.net>
> Subject: Re: [600MRG] K3 transverter operation
> 
> I loaded the latest firmware into my K3( been a long time since it was updated) and have been struggling to get the transverter interface to work.
> 
> I have set the configuration as the manual says and turned the interface to normal. The if is set to 10 MHz and the power to 1.5 mW but when I key it I get a 10 watt  10 MHz signal at the main antenna and nothing at the transverter out jack. 
> 
> Anyone out there with a K 3 have any idea what I am doing wrong?
> 
> Pat
> Xct 
> 
> 
> 
> 
> Sent from my iPhone
> 
> On Apr 29, 2014, at 5:28 PM, Eric NO3M <no3m at no3m.net> wrote:
> 
>> Pat
>> 
>> Yes, you can now use 10 MHz for a transverter IF in the K3.  Grab the latest firmware; you may need to get the BETA release, not sure if the changes were merged into the production release yet.  You may have to tweak your 30M BPF, see Wayne's comments below:
>> 
>> ===
>> 
>> The attached K3 field-test firmware adds 10 and 18 MHz as transverter I.F. selections in the CONFIG:XVn IF menu entry. Please let me know if you get a chance to try either band.
>> 
>> (For various technical reasons, it would be harder to add the 1.8- and 3.5-MHz bands as I.F. selections, though this is still on the list for future consideration.)
>> 
>> Note that the K3 uses narrow band-pass filtering, optimized for the ham bands. In the case of 10 MHz, we align the BPF at 10.1 MHz. If you plan to use the K3 with a 600-meter transverter and a 10-MHz IF, this puts the IF at about 10.5 MHz. You may find that the receive gain could be somewhat lower at this frequency. If this is an issue, you can easily adjust the 30-meter BPF to handle both the 10.1-MHz end and the 10.5-MHz end of the passband.
>> 
>> To do this, inject a strong signal at 10.5 MHz, tune it in, and while watching the S-meter, peak trimmer capacitor C179. Then inject 10.1 MHz, tune that in, and peak C183.
>> 
>> This may result in some ripple in the filter's passband. But the peaks will be where you need them -- in both the ham band (10.1) and at the required I.F. for 600 meters (10.5).
>> 
>> You should also verify that the K3's synthesizer is working well at 10.5 MHz. Tap DISP, then use VFO B to locate the "PLL1" voltage display. Tune the VFO from 10.1 to 10.5 MHz while watching this voltage. It should remain between about 1.5 and 7 volts. If the voltage goes outside this range, or you seen an asterisk (*) in the PLL1 display, re-run the VCO CAL routine described in the owner's manual. Hopefully this will not be necessary, though I did find one K3 that required this step.
>> 
>> I didn't hear any inherent receiver spurs when tuning from 10.475 to 10.525 MHz.
>> 
>> 73,
>> Wayne
>> N6KR
>> 
>> ===
>> 
>> 
>> 73 Eric NO3M / WG2XJM
>> 
>> On 04/29/2014 05:22 PM, Pat Bunn wrote:
>>> Eric,
>>> 
>>> Did Elecraft ever release a firmware change to allow a 10 MHz transverter IF for the K3? I see that you are using a K3 for 600 meter transverter operation .
>>> What IFs are you using in your setup?
>>> 
>>> I am in the process of building a transmitting converter for my K3 . I have a 10 MHz input card coming from Elecraft and have a GPS disciplined source in the shack driving all my HP signal generators.
>>> 
>>> Thanks
>>> 
>>> Pat
>>> WG2XCT
>>