[hpsdr] Hermes/ANAN-10 RX spurious signals?

[Dick]

It's just a matter of availability, the brass I can just run down the 
street and get, the PCB material I'd have to order.

Dick KD4JP

On 11/12/2012 10:03 PM, Berndt Josef Wulf wrote:
> G'day Dick,
>
> you also could use a single layer copper cladded PCB cut to size with
> the copper turned to the "safe" side.
>
> 73, Berndt
> VK5ABN
>
> On Mon, 2012-11-12 at 20:56 -0500, Dick Lichtel wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> I looks like the 10MHz noise can be reduced from an S7 to an S2 by
>> placing shielding over the 10MHz osc area. I tied the shielding to
>> ground via copper foil tape to the 10MHz Clock  SMA connector.
>>
>> The 10MHz osc is directly below the ANT1 input on the amp causing the
>> clock to couple with the RX input... which is why moving the Hermes
>> board in and out of the cabinet changes the noise strength.
>>
>> It might be possible to place a shield in a slot  above the Hermes board
>> in the cabinet. I only needs to be about 2" in depth. I'm thinking that
>> a piece of brass or copper  from ACE hardware could be cut down to size
>> to fit. It is probably a good idea to coat the metal with something not
>> conductive to be safe. I'll try this tomorrow to see if the results are
>> similar to placing a small shield over to the osc. area.
>>
>> I suspect a similar approach can be taken for the 25Mhz clock, but I
>> have to look at the schematic and board layout in be sure.
>>
>> I think it was a bad idea to have the Hermes board face up in the
>> cabinet. The spurs probably wouldn't be there and we won't have to
>> solder those tiny rf connectors. We would need to new face plates to
>> mount the Hermes board backside up.
>>
>> Dick KD4JP
>>
>> On 11/12/2012 6:17 AM, Bruce Beford wrote:
>>> Thanks, Dick.
>>> I am glad you have had a chance to experiment with this a bit. I won't be
>>> able to work with mine for a week. Please keep us posted on your
>>> progress/observations.
>>> 73,
>>> Bruce, N1RX
>>>
>>> ________________________________________
>>> From: Dick [mailto:dick221z at gmail.com]
>>> Sent: Sunday, November 11, 2012 10:11 PM
>>> To: Bruce Beford
>>> Cc: hpsdr at lists.openhpsdr.org
>>> Subject: Re: [hpsdr] Hermes/ANAN-10 RX spurious signals?
>>>
>>> Since the position of the Hermes board in the case seems to affect the 10MHz
>>> spur, I tried putting the Hermes back in position and sliding bit of
>>> shielding over the A/D  area, about 1/2 spacing above, not grounded. This
>>> reduced the 10MHz spurs by about 2 S units. So it looks  like some shielding
>>> is needed over the analog section.
>>>
>>> I'll look into making something more practical that can be grounded later on
>>> in the week.
>>>
>>>
>>>
>>>
>>>
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