Re: [softrock40] Re: 6m Ensemble RXTX
- Like people said, the CMOS switches in the Softrock radios don't work well above 10m. The VHF Softrock receiver uses a preamplifier and mixer in front of the QSD; a VHF transmitter could be designed using a similar approach but the Softrock series does not yet include such a design. Other SDR designs that cover VHF or UHF bands use different front ends: either a mixer for downconversion or a high speed DAC for direct sampling at the receive frequency. (Or they just have poor sensitivity like those DVB sticks.)The C version of the Si570 has enough range (barely) to cover 6M; for normal sampling you need an oscillator frequency of 4x the operating frequency. (Subharmonic sampling is another possibility; the fixed-frequency Softrock Lite radios use that on the higher bands.) The more expensive A or B versions would cover 6M easily.On Sun, May 12, 2013 at 2:51 PM, Adam Jacobs <jacobs.adam@...> wrote:This is something like the road that I am planning to go down when I get some time. I have the 6m transverter that mates to the FT-101. The transverter (supposedly) works, but I don't have an FT-101 to supply all of the various tube plate voltages and such. I scored a broken FT-101 and grabbed the powersupply components, the idea is to build a separate supply for this unit and make a standalone 6m transverter for use with my FT-840. However, I'm not convinced of the receive potential of a tube transverter. Maybe I'm wrong, we'll see. :) So I was planning to build out a 6m Ensemble VHF RX for the receive path.-73 Adam W7QIOn Sun, May 12, 2013 at 8:27 AM, Zack Widup <w9sz.zack@...> wrote:
The VHF Ensemble II works quite well on 144 MHz as a receiver. I think
I mentioned here before that it compares with my Yaesu FT290RII which
needs a little assistance for weak-signal work. An LNA preamp does
great. I use mine mainly as a microwave IF on receive so I only have
to watch the display while peaking a signal with the dish, not have to
try to move the dish with one hand and tune a receiver knob with the
I suppose for a transceiver you could use the RXTX with an additional
73, Zack W9SZ
On 5/12/13, Alan <alan4alan@...> wrote:
> ----- Original Message -----
> Subject: [softrock40] Re: 6m Ensemble RXTX
>> Well I got an email that the si570 and multiplexers in the kits won't do
>> much above 10meter. So it looks like I'll need to do
>> some research and see if there are pin compatible replacements that will
>> handle the frequency range.
> No, the Softrock Ensemble does not seem a good choice for 6m. You can use
> subharmonic mixing but sensitivity is poor. A preamp would
> But there is a VHF Ensemble with a mixer. That may be built for 6m and
> performs well.
> As Alan says, the UHFSDR can be built to go much higher. I'm not sure that
> is quite as straightforward as a Softrock? I'll have to
> try one some day.
> 73 Alan G4ZFQ
>> --- In email@example.com, "kb9gpm" <goofy_36@...> wrote:
>>> I'm curious about something. Has anyone tried to build an Ensemble RXTX
>>> to work on 6 meters. It seems like it would be a matter
>>> of changing the receive and transmit filters. I'm also assuming the
>>> si570 in the kit will run up that high.