[hpsdr] New Hermes 2M Board.

[Isaac Weksler]

Hi,

 

Excellent news. Best news since Apache took over and the HPSDR boards became much less affordable than those manufactured by TAPR. Understandably so since they have been sold non-profit as fits open project. I hope the new Hermes 2M will stay that way.

 

I'd like to be added to the list of interested.

 

Some thoughts I'd like to share.

Concerning the 2m band. I am with those who say that it's preferable to have a 300Msps ADC. And thinking about a new ADC it would be great to have it dual channel allowing diversity and pure signal stuff.

I looked into what's available to replace the currently used  LTC2208 priced at about $90:

1.      If decided to stay with 16 bit resolution, then this looks reasonable:

AD9652 - 16-bit, Dual, 310Msps, 87dBFS SFDR – priced at about $300

2.      However, if 14 bit resolution seems to be sufficient this A/D looks as a good candidate:

LTC2158-14 – 14-bit, Dual, 310Msps, 88dBFS SFDR – priced at about $200

 

These are of course more expensive that the LT2208 currently used (which is 1 channel 250Msps) priced at about $90.

 

Accordingly D/A should also be dual and with the with the matching update rate. Possibly one of these alternatives:

1.      AD9781 - 14-bit, Dual, 600Msps, Parallel/LVDS, 78dB SFDR, 0.44W Power – priced at about $21

2.      AD9787 – 14-bit, Dual, 800Msps, Parallel, 82dB SFDR, 1.05W Power – priced at about $27

 

Compared to $18 for currently used AD9744.

 

Kjell, hope this helps in your very welcome and blessed efforts.

 

73 Isaac 4Z1AO

 

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