this is 144MHz 2.0 not 10 or 6m..

SPF5189z Low noise preamp 23cm

14-4-2018 updated

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

Tested 2 small porto antennas
1 Baofeng UV antenna left 2nd best signal on PI2NOS
2 eBay DIAMONDSRH805S wide band 144/432/1200 it works for its size as expected
3 piece of wire : best signal in the setup...

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 ?
I suspect eBay …

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?
I got curious to look inside. Maybe moisture penetration degraded the antenna.
This antenna is rainwater close in its normal vertical mounting position. But take care if your mast can b…

Nice opening10m and 12m to S.A.

SFI low 70 a 16 K3 still 10m opened up in afternoon to N-Italy EA5 F JN33
F/PD0OHW/M in JN33 decoded 150mW

VP8LP 12m 2-way with GP 7m ag swr 1:3

60m 5,362 open to ZL every? morning

PA0O ham radio

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