Re: [softrock40] Re: softrock lite II in 10m
- Hi Bob,
It seems that 74AC74 is able to use clock till 125MHz (@5V). It is used in Ensemble, which work in 10m too.
What if I will modify the oscillator to work at 3rd harmonic of an x-tal of around 9.x MHz (by using a tuned circuit?
On 11/28/2010 12:08 AM, g8voip wrote:
It should be possible to modify a LiteII to work on 10m, however there is a major problem to be overcome.
You will see until the LiteII kit was revised earlier this year to make the 'combined' kit version, a 15m version was included in the range.
The 15m version used 1/3rd sub-harmoinc mixing, so the QSD clocks ran at 7MHz. This creates the problem that as well as responding to the wanted 21MHz signals, the receiver will also receive 7MHz signals. Given the strong ham and commercial stations around 7MHz, these were audible on the 15m version. A decision was taken to drop that option on the grounds of poor performance.
As far as I am aware, there has never been a 10m version of the LiteII, but I would suspect using the same 1/3rd sub harmonic sampling, there would be problems caused by strong broadcast stations in the 9 - 10MHz region.
There was a special 10m SoftRock v7.0 RX kit produced that worked very well, used a different approach. Got one here in my collection.
One approach might be worth trying with a LiteII would be to replace the LO with one operating at 28MHz x 4 to overcome the sub harmoinc sampling problem.
73, Bob G8VOI
--- In email@example.com, Dan <danto@...> wrote:
> There is anybody here trying to make a Softrock Lite II work in 10m band?
> I intend to add to my websdr server the 10m band too, and I wonder if I
> can still use a slightly modified Softrock Lite II kit (which according
> with specification can be build only till 20m).
> WebSDR: http://yo3ggx.1p.ro:8765/