[Elecraft] K? for remote rx only

[David Cutter]

Thanks for those notes, Geoff.  It did cross my mind that I would probably 
need some home to site link to avoid continuous transmission and switch 
between the amplifier front end filters or complete amplifier/TRF.  For a 
start this would be an additional challenge for the battery supply and 
reliability of the system and I would avoid unattended transmissions.  I 
would use high gain, directional antennas at each end of the microwave link 
to keep tx power down and avoid QRM in that band.  I would provide good 
filters to avoid bc QRM and I note your comment about core-generated IMD. 
Initially I was considering only pointing at North America with one aerial 
to get the hang of it and that should avoid most night time Eu bc QRM.

As to modulating a microwave signal with as much as 7.2MHz, I don't know 
either, but I'm hoping I can purchase the microwave bits as off the shelf 
products, so, that will be part of my search.

I wondered if there might be front end parts of Elecraft products that would 
do some of the work and I would look at amplifiers off the shelf to 
interface to the Beverage.

Thanks, again, Geoff and seasons greetings to you and all on reflector.

David
G3UNA



> David,
>
> My XYL and I have been away, so my apology for being slow to make a 
> comment.
>
> If your remote Beverages are to be used on 160m, 80m and 40m, and a remote 
> TRF is used on each band to provide selectivity and gain, then unless 
> their outputs are combined before up-conversion then obviously you would 
> require a home-to-remote site link to band-switch the TRFs.
>
> Of course I have no idea as to the level of BC signal(s) etc your 
> Beverages would present to the TRFs, but as you know the size and mix of 
> all Iron/ Ferrite cores used in the system (including the combiner's) must 
> be chosen with care to prevent "Core Generated IMD" becoming a "problem".
>
> Another difficulty which might arise in an up-conversion scheme is the 
> generation of intermodulation products, either by the up-converting mixer 
> or by any subsequent stage.  This makes me wonder whether it would be 
> better to run the 160m, 80m and 40m TRFs continuously, and view their 
> combined outputs as "Baseband".  Then use this "Baseband" signal to Angle 
> Modulate (FM or PM) the microwave transmitter at the remote site.  At the 
> home site the recovered baseband from a FM/PM receiver would be the 160m, 
> 80m and 40m bands.  Of course a home-to-remote link would not be required.
>
> Here I must put my hand up, because it has been a -long- time since I 
> designed any microwave kit, and I cannot recall if a "Baseband" extending 
> to 7.2 MHz is feasible.
>
> Best wishes to you, David, to all on the "List", and to everbody at 
> Elecraft for the New Year when it comes!!
>
> 73,
>
> Geoff
> LX2AO
>
>
> On December 22, 2012 at 2:40 PM, David Cutter wrote:
>
>>I want to place Beverages at remote sites (for rx only), for 160m (useable 
>>on 80 and 40m), but it's not viable to use a K0 at each site.  Is there a 
>>way to use a simpler system: perhaps a TRF on each band, up-converted to, 
>>say, 2.3/2.4GHz then down-converted to each band for my K3 at home.  The 
>>transmit antenna will be at home and listen in diversity mode.
>>
>> I can see various issues like image and sensitivity cropping up, but I 
>> just wonder if this has been done.  It would be nice if there was a lower 
>> cost K series simple remote receiver available.
>