[Elecraft] (no subject)

[Georges Ringotte F6DFZ]

Hi to Geoff and to the Group,

Geoff said :
Although the Hilberling PT-8000 series of transceivers are very expensive, 
this could be because they have been designed for Military and 'commercial' 
use and not only for amateurs.  I believe that it should be possible to 
design and market a high performance transceiver using an up-conversion 
architecture, whose selling price is reasonable for most amateurs.Yes, it's built like a RS instrument and a lot of money went also with its 200W, 2 receivers, 144MHz coverage, high end power supply, all filters included...  The results I have of tests 
performed by other people and myself, show that the level of odd order IMD 
generated by a crystal ladder filter using a given quality of quartz 
increases as the filter's bandwidth is decreased. This is surely one of the reason why the Hilberling uses a 50 kHz wide VHF roofing filter.This remind me of the 50 years old debate about SSB generation and the choice between filter or phasing generation.Filter generation was considered like a brute force method, and phasing a soft one.Down conversion with ultra narrow filters is somewhat brute force, up conversion with large bandwidth filters is a softer method.Just my opinion ! Regards Georges F6DFZ