HF preselector

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Paul
Posts: 355
Joined: Fri Feb 17, 2017 9:52 am
Location: SW UK

HF preselector

Post by Paul » Mon Jun 04, 2018 7:46 pm

For the sake of other "newbies, I thought that this illustration of the use of an HF preselector (suggested to me by a knowledgable contributor) may be helpful.
From top-to-bottom...
Images show AM breakthrough at a frequency of interest, firstly, with HF preselector used (no MW filter), secondly without HF preselector (but with MW filter) and lastly, without either MW filter or HF preselector.
It believe that it rather illustrates how useful/effective an HF preselector may be.
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mark.
Posts: 51
Joined: Tue Oct 03, 2017 9:14 pm

Re: HF preselector

Post by mark. » Mon Jun 04, 2018 8:56 pm

What kind of signal level are you getting on the BCB signals when directly monitoring them? I have a bunch that go from -50 to -25 and I don't see their images at the 4650 khz like in your example. I have no external filters or the built-in MW filter in my RSP1. Are you by chance running an antenna with a preamp that may be overloading?

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Paul
Posts: 355
Joined: Fri Feb 17, 2017 9:52 am
Location: SW UK

Re: HF preselector

Post by Paul » Tue Jun 05, 2018 5:41 am

Hi Mark
My original post was simply inteded as an illustration of the effect of an HF preselector for other "newbies," who like me, may never have used one before and not intended as an example of the receiver's use.
I am quite happy to admit that I am still at a low-point on the learning curve and hope that others at a similar point on it may find it useful.
The antenna in use was a Wellbrook and as you may have noticed, the gain reduction slider (RSP2 default) was at minimum and of course there is scope to decrease the gain, but in answer to your enquiry, I hope that this typical in-band AM signal may provide a fair example of this set-up, again without employing gain reduction.
This particular brodcast was received at S44 to S50-ish most of the time, but varied slightly and is fairly typical of what I may usually expect with the associated settings.
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