[NLRS] Do MAR-4s REALLY suck this bad?

[Zack Widup]

Hi Scott,

I have very rarely needed an inductor on a MAR device on the power lead. I
know they recommend it but usually it's not needed. Even with dead-bug style
construction I've found all but the MAR-8 to be unconditionally stable.

Try the circuit with just the resistor and see what happens.

I'd also suggest swapping the MAR-4 out with another one before going to
another device. I've had some variation in performance from piece to piece
with the MAR's sometimes.
I'm always experimenting with different gain stages. If one gives me too
much gain or too little, I'll swap out with a different device and put in
attenuator stages if needed. That's my idea of fun!
:-)

73, Zack W9SZ
On Tue, Nov 18, 2008 at 9:16 AM, Scott <acepilot at bloomer.net> wrote:

>
>
> I added a MAR-4 to my to my TX IF (144 MHz) to get the drive up for my 10
> GHz transverter.  I'm getting 5 dB gain at 144 MHz.  Should be getting 8 dB
> or so.  I'm driving it with -7 dBm at 144 MHz. The DC supply is 9V through a
> 75 Ohm resistor giving 5.25V at the output lead of the MAR-4 which is right
> on the money.  I slipped a ferrite bead on the resistor lead on the MAR-4
> side.  It's kinda big and lays on the circuit board trace over the output
> lead.  Could this be "choking" the 144 output from the MAR-4?  I could
> actually build the choke with some #20 enameled wire to keep the ferrite
> away from the trace...
>
> --
> Scott N0EDV
>
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