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DELL OPTIPLEX as radio PC and Eminent w-lan router

Purchased an Dell Optiplex GX620  P4 3.2GHz HT  75GB HD  small quiet PC  occasion for 99€. Has the trusty XP  OS  so i hope to got rid of the communication hangers with the USB-serial i have with W7pro 64b  and N1MM  Also i wanted to have a WSPR N1MM dedicated PC in the shack.
This one is RF(almost) and audio-wise quiet and has low power consumption for 24x7x365 purpose.

I gave up W7pro-64 with N1MM and USB-serial converter it is not stable i have to reset the interface too often it is meshing up my logging and it is a nerving me.. Until now no hangups it is quiet almost forgot it is running on the desktop.

In the same shop i purchased an Eminent Em4570 router  to replace the  RF  noisy Linksys WRT54G with its build in 2 step-down very noisy switchers i could not silence the RFI in 14-30 MHz band.
This Eminent seems to be of higher quality  it has a metal case  whereas the Linksys is in a plastic box.
The WRT54G has 2 external antenna connections of type reverse-TNC  i use an outdoor Antenna over a short RG213 2x N cable to a double loop reflector antenna  and have a RP-TNC to N-Female adapter for that.
But  EMINENT uses 3  SMA smaller types for 3 whip antenna's
This is the SMA connector at the EM4570   it is confusing but this seems to be a RP-SMA-Female with pin!
And the counter part is the RP-SMA-M male with jack...  Confusing a reverse polarity male is a female...
A sort of lesbian SMA connector.

above is the connection at the EM4570 whatever it is called...

 For the outside antenna  I need an other N-SMA adaptor. The WIFI range supposed  to be improved against the WRT54  
But i still need an outdoor antenne with snow at the roof the signal is to weak over 50m

The Dell Optiplex GX620  mini desktop still has all the connectors needed for Hamradio

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Good RF gasket shielded cover plate.
external power adapter 12V 18A the black box behind  QTX 500kHz tx..
Some carriers heard on 28Mhz from the PC / Power not very bad  smal band signals not localized where from. Uncovering the PC did not raise the strenght of the cariers.  


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SPF5189z Low noise preamp 23cm

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Above the low noise  preamp 50 - 4GHz    ebay  6€

Tested  2 small porto antennas
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Unit under test at workbench.
It was stable  50mA  at 5V   few days,  but sudden the current went up to 100mA
And i could  no longer adjust it with the negative bias Voltage.
The - Voltage went to zero and the SPF input port became low Z.
This SPF5189z was broken  no oscillations, no input overload just it broke while i was receiving the PI2NOS 430.125 using a small antenna at the workbench.

The specs of  SPF5189z  say it has an internal circuit  regulating the bias current.
Replaced . again   with an other of the 5 spare SPF i have.
The new one again could be adjusted at 50mA  5V 
The current raises to 150mA  when removing the  negative gate voltage.
Where is that internal bias circuit ?
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2011-01-22 DIAMOND X30 2m 70cm 1m30 Colinear inside

Having relative poor signals on the local 70cm / 2m channels using this Diamond collinear 70/2 combi antenna at a height of 25m. I needed to investigate what could be wrong.
Measuring the cable only 3W is left for the antenna of the 10W 435MHz output from a IC451E
The cable is 30m type H100 Z50 10mm outside diameter it is semi air-spaced but has an impossible 4mm² solid CU inner conductor not much air left. I preferred the H43 Z75 cable having lower loss and mechanical better ratio in conductor size but it is no longer selling i think. This H43
3W should be enough for a comfortable noise free FM signal. But only 27km away at PA0A the signal is weak too weak something must be wrong? I made a simple reference dipole of 2x17cm CU wire.
With this dipole the signals where totally worse. So the Diamond does work?
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This  antenna is rainwater close in its normal vertical mounting position. But take care if your mast can b…

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