[hpsdr] [!! SPAM] Penelope / Hermes use as VNA: Driver problems?

[Phil Harman]

Hi Sid,

That's a very nice bridge for sure. There's some alternative designs on
this site:

http://www.wetterlin.org/sam/

Sam has a wealth of very useful information regarding VNAs here.

73 Phil...VK6APH


> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi Helmut,
> DB1CC has a RF Return Loss Bridge on hiqsdr.org that's used with the
> HiQSDR in VNA mode.
> I've just got to make the PCB's and put it together, the toroids are
> already on the pieces of coax.
> 73 ... Sid.
>
> On 15/08/12 15:07, Helmut, DC6NY wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Hi Raj,
>>
>> good question. I suppose you have to add a 10dB or better 20 dB pad into
>> the
>> path. There is plenty enough dynamic in the system.
>>
>> 73 Helmut, DC6NY
>>
>> -----Ursprüngliche Nachricht-----
>> Von: hpsdr-bounces at lists.openhpsdr.org
>> [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Raj Dewan,
>> N2RD
>> Gesendet: Mittwoch, 15. August 2012 15:42
>> An: hpsdr at lists.openhpsdr.org
>> Betreff: [!! SPAM] [hpsdr] Penelope / Hermes use as VNA: Driver
>> problems?
>>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> I have a question regarding use of Hermes or Penelope/Mercury as a VNA.
>> I had heard that the driver in both of these was sensitive to low
>> impedance and would possibly be damaged if shorted.  How would that
>> affect the use as a VNA as a shorted load is a standard calibration.
>> Does one need a pad or is one built in to deal with this issue?
>>
>> Raj, N2RD
>> Owner of Penelope/Mercury, Hermes ordered. .
>>
>
>
> --
> Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
> Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
> Senior Staff Specialist, Cricket Coach
> Microsoft Windows Free Zone - Linux used for all Computing Tasks
>
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