[hpsdr] Follow-up on Hermes-Lite

[Steve Haynal]

Hello Roderick,

Please remember that the 2 RX in the Hermes-Lite and  5 RX in the Hermes
use the same input and ADC. So 1 detector lets you listen to multiple bands
on the same antenna. If you are interested in an inexpensive VNA, checkout
another project of mine: https://code.google.com/p/pysdrvna/

73,

Steve
KF7O



On Wed, Apr 16, 2014 at 2:52 AM, <rodwall1234 at gmail.com> wrote:

>  Hi Steve,
>
> Thanks for your reply. As I’ve indicated,  a VNA for $150.00 would be
> great. And if it can have two Rx detectors it would be even better to do
> Reflection and Transmission measurements with out having to change the
> connections to the DUT.
>
> Good luck with the development, I’ll like to build one and help test it
> when ready.
>
> Regards,
>
> Roderick Wall, vk3yc.
>
> *From:* Steve Haynal <steve at softerhardware.com>
> *Sent:* ‎Wednesday‎, ‎16‎ ‎April‎, ‎2014 ‎1‎:‎48‎ ‎PM
> *To:* hpsdr at openhpsdr.org
>
> Yes, the Hermes-Lite should be usable as a VNA, although I have not tested
> this. Currently, it runs in half-duplex mode. I tried full-duplex but had
> some issues with noise at various front-end gain levels. I have asked ADI
> for help with this. You will have to use full-duplex for the VNA and the
> levels of noise I saw probably won't matter much for a VNA. Ideally, I'd
> like to see half-duplex for regular operation to keep the power consumption
> low, and then switch to full-duplex when needed for a VNA.
>
> The design is now only 1 RX and 1 TX to keep the compile time down. The
> limitation yo will run into when compiling with 2 RX and 1 TX is not enough
> RAM resources. The Hermes had some large buffers because I believe it
> could. These will have to be reduced to fit 2 RX and 1 TX.
>
> 73,
>
> Steve
> KF7O
>
>
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