On Mon, 2009-06-15 at 16:08 -0600, David Feldman wrote:
> > >
> > Yes, getting rid of the harmonics of 22 and 28 at 44 and 56 MHz at the
> > transverter output. That's why TenTec didn't sell a 28 to 50 they made
> > it 14 to 50 to move the harmonics further away from 50. Or have lower
> > order harmonics to filter.
> >
> > 73, Jerry, K0CQ
> >
> >
>
> Thanks, Jerry - that is very helpful; I'll let the 1208 go and start search
> for some basic 10/VHF transverters...
>
> 73 Dave WB0GAZ
>
Those harmonics are a problem in any 28 to 50 MHz transverter, why some
use 14 to 28 to reduce the problems, especially with the 2nd harmonic of
the crystal. Down East Microwave, DB6NT, and Elecraft are the current
builders of transverters found mostly world wide. Also SSB of Sweden.
All make various models for power, IF power and controls. Fundamentally
the mixers used need a milliwatt or less of IF power so lots of power
has to be lost somewhere between the HF rig and the mixer, then
amplified back after mixing and filtering. You can win with a super high
level mixer, because it requires a higher level of injection anyway and
its just as easy to amplify the mixed signal as the LO and the
transverter runs cooler that way. The Tentec kits were by far the lowest
priced transverters on the market in the past decade or more. But I
found the receiver in mine a bit low on performance and I've gone to
other techniques for 6m. Right now my favorite is a Yaesu FT-857 needs
no transverters for 6, 2, or 432 and I made over 200 contacts over the
weekend, mostly on 6 with it.
73, Jerry, K0CQ
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