[hpsdr] Epi idea

[Phil Harman]

There may be a simpler way to do this.  Both Mercury and Penelope will respond to, and generate,  alias signals.  For example, if Mercury is  using a 125MHz clock and it is tuned to 19MHz then due to aliasing there will also be responses at 

125 - 19MHz = 116MHz 
125 + 19Mhz = 144MHz

Normally for HF use these signals will be rejected by the input filters. 

With the LT2280 evaluation board I'm using to prototype Mercury the sensitivity at 144MHz is only 1dB lower than that at 19MHz.  In the design of Mercury we have allowed for the switching out of the input filters. So, with a suitable pre-amp and filter Mercury will work on 2m. In fact I've just been listening to the local 2m repeater using the prototype! 

Similarly, we can tap the output of the DAC on Mercury and have a few mW on 2m which again can be amplified and filtered to give a 2m signal. 

73's Phil...VK6APH 










  Tony Langdon <vk3jed at gmail.com> wrote:
  >Another thing, it would be nice to have at least the full 4 MHz range 
  >of 2m in the transverter, possibly even more, if there is any intent 
  >to use it as an IF for higher bands. And the IF for the transverter 
  >could be anywhere. Is it better to have it in or out of a ham band?

  With software, I couldn't see why this couldn't be possible. At least have the ability of the LO in the transverter to change frequency to provide the full 4 meg range. But it would be a lot easier (I think) to go 28-32 Mhz via Penelope and Mercury.

  >Full duplex would be nice. Satellite work is normally crossband 
  >though. Full duplex on 2m in this instance is probably going to be 
  >most useful for L/V, L/S and higher microwave bands, where the 2m I/O 
  >is being used as an IF.

  That's the idea of separating the TX and RX of the transverter to provide this cross-band function. Especially since Penelope and Mercury are separate themselves. Plus the TX or RX could have the ability to be bypass.

  I think it should call it an IF Upconverter (IFU) instead of a transverter so we can reduce confusion.

  73's Chris N0TTW





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