Re: RXTX modifications
- Hello Sandro
I think modification for 20/17/15m is not so difficult.
Local oscillator Si-570 will cover all bands of HF.
Frequency is set by the software such as PowerSDR V.19.3.15(*),
other SDR software and you are able to set any band,frequency.
I have been using this PowerSDR software.
The band:160/80/60/40/30/20/17/15/12/10/6 m will be set by
Even if you modify to 20/17/15m bands, you can receive other
bands,but the sensitivity goes down for other bands.
Transmitting for other bands is another story.TX output LPF
(Fc=24MHz) limits maximum frequency.
Please note that tune circuits are designed forgcenter band",
20/17/15m (for your modification) : 17m
and as the result, a peak sensitivity will be set atgcenter bandh.
> Hi Taka,
> The modification of the LPF appears to be well-suited for new bands. Thank you for facilitating the calculations.
> I do not know how the fimware for the selection of frequencies. 10m to 160m operating range, limited only by the LPF?
> Just follow your suggestion and is ready to change, right?
> PY1PE Sandro
> ps: Sorry English, but is the translation of google.
> --- In email@example.com, "taka_sugi1206" <taka_sugi1206@> wrote:
> > Hi, Sandro
> > I didn't understand the word "motagem", Portuguese?
> > but I guess this means "ensemble".
> > Anyway,I simply calculated each parameters for 20/17/15m set.
> > Basic idea@: center frequency of the set=18MHz(17m)
> > 1. Tune circuit : f=1/2Îã(LC) at 18MHz
> > 2. TX Output LPF: cut off frequency fc=24(MHz)
> > fc=21MHz x 1.2
> > This is defined by max. frequency of the set:15m(21MHz)
> > Estimated parameters@for 20/17/15m set modification.
> > T2: T30-6@Primary: 10t/Bifilar 0.36uH
> > Secondary: 20t/1.44uH
> > C20: 56pF
> > T3: same as 30/20/17m
> > T4: same as 30/20/17m
> > L1: T30-6/18t 1.17uH , C21: 68pF
> > L2,L3 : T37-6 12t/ 0.43uH , C24,C26: 100pF , C25:220pF
> > C27: 100pF , L4: same as 30/20/17m@
> > C39: 120 or 150pF , T5: same as 30/20/17m
> > T6, R55/R58 : same as 30/20/17m
> > Please comment on this idea.
> > 73 DE JA1TLH/Taka