[Elecraft] KX3: How much space inside?

Wed May 25 14:05:12 EDT 2011

Here's another member of the group offering unsolicited product design ideas to Elecraft...which they surely don't need, but I know they welcome. 

My "big wish" product for Elecraft would be an adaptation of the K3 with multiple slots for small-ish transverters to make a pure VHF/UHF rig.

I'm thinking of an up-to-date version of the Yaesu FT-936R, which was and still is very popular with the weak signal VHF/UHF crowd. It has four slots for band-specific modules. The rig came standard with modules for 6 meters and 2 meters installed, and two open slots that you could fill with 220, 440, and/or 1296 mHz modules. One could also remove the 6 meter module and use all four slots for vhf/uhf bands.  Hams could buy the bare rig and as many or as few of the band modules as they wished (sort of a precursor of the K3 modularity, but more limited than Elecraft's offerings). Even today, with all the whiskers the 736 has grown over the years (and its mediocre sensitivity), the "scarce" 222 mHz and 1296 mHz modules fetch $400 to $800 on eBay.   

That, I think, indicates how much demand there is for a rig tailored specifically for the VHF/UHF contesting crowd, EME and satellite work.  

The 736 modules put out 25 watts except for 6 meters. Each band had its own antenna jack, facilitating attachment of amplifiers as desired with less band-switching complexity. 

I can envision a "K-4" line based on the K3, but with the inside reconfigured to accept transverter boards plugged into a mother board. If they could be engineered to output 16 watts, you could get 500 watts out from a dedicated one-band amp with 15 dB gain. With 25 watts out, you could reach 800 with an amp.  The band-specific amps could go into a separate box or boxes, "plug and play" with the K-4.  That would create a great weak signal VHF/UHF setup! The K3 is a marvelous IF strip as it stands. This would make a more compact and purpose-specific rig than the K3 plus separate transverters, since you need a K3 plus a transverter plus a separate amp for each band to output 500 watts on any UHF band. 

To achieve this, you'd have to take over the space inside the existing K3 that's used by the internal HF amp and ATU, and maybe the space allocated for a second receiver (although a second receiver would be quite valuable for contesting purposes).I don't know how much re-engineering it would take to reduce the current line of transverters to a form factor that would fit inside the "K4".  You could also pick up space by making the "motherboard" a single-band 28 mHz IF strip, plus capability for 6 meters and maybe 2 meters, depending on available space. 

The circuit board for the current Elecraft transverters has about 65 square inches.  One could fit a "daughter board" into the K3 that would have about 25 or 30 square inches, so I think the existing transverter circuit design could be laid out on two  "back to back" circuit boards that would comprise a one-band module that would be about 2 inches thick; you could install at least four of such modules in the K3 form factor.

That's my 2 cents worth on the "next big idea" coming out of Watsonville.

73

Lew K6LMP

On May 25, 2011, at 9:29 AM, Wayne Burdick wrote:

> We're leaving "hooks" in place for either a 2 m or 4 m transverter (or  
> possibly both) in the KX3. It would be in the ~5W range, and would  
> substitute for the optional ATU. If you needed both the transverter  
> and an ATU, you'd need to use an external ATU such as the Elecraft T1,  
> which can be band-switched and remotely tuned directly from the KX3.
> 
> 73,
> Wayne
> N6KR
> 
> On May 25, 2011, at 8:36 AM, Jens Petersen wrote:
> 
>> On Tue, 24 May 2011 14:24:00 -0700 (PDT), you wrote:
>> 
>> 
>>> The other thing that would be a huge selling point in Europe if it  
>>> could be
>>> designed in is support for the 4m band. There is no radio that  
>>> covers 4m
>>> apart from a couple of cheap Chinese FM handies.
>> 
>> Oh yes - Hilberling does:
>> http://www.hilberling.de/bo/bo_pdf/pt-8k-2010_folder_a4a3.pdf
>> 
>> -- 
>> OV1A Jens
>> 
>> Sent from my desktop PC with a nice big screen and a real keyboard.
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