Hi Laurence,
Yes, there is a jump in sensitivity when the internal preamp
is switched out (IPO on). This is again probably because of the
inappropriate reactances (for LF) in the preamp.
I was listening to 80m on the miniwhip this evening and was impressed
with what I heard, considering the whip was just hanging from the
ceiling in the shack.
Can you tell me about the L400b?
73
Joe
On Sun, 2 Apr 2006, Laurence KL1X wrote:
> Joe - on 137Khz does your sensitivity improve with the IPO enabled on the
> 817...? its very deaf without a lot of drive but with the L400b eprobe it
> shoves enough signal - without it and on my loop arrays I needed something
> like 20dB gain to get things "hot". I agree on the modification!
>
> Laurence KL1X in 5
> okie em26br
>
>
>
> from the manual -
> "IPO (Intercept Point Optimization) - Bypasses RX Preamp on HF/50 MHz for
> improved performance during strong-signal conditions."
>
>
> >From: Joe Craig <[email protected]>
> >Reply-To: [email protected]
> >To: [email protected]
> >Subject: Re: LF: T/A April 2
> >Date: Sun, 2 Apr 2006 21:49:00 -0230 (NDT)
> >
> >Roelof and group,
> >
> >I was using an ft-817 with the miniwhip and was quite amazed that
> >the LF TX could be heard at 20km. I will try the attenuator between the
> >rig and the miniwhip next time to see if the intermod is from the RX.
> >Thanks fort the suggestion.
> >
> >The ft817 is very deaf below 0.5 MHz because of the small inductive
> >reactances in the front end and mixer xfmr I believe, but modifying
> >it would be awkward because of its size.
> >
> >Joe
> >
> >
> >
>
>
>
>
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