[R-390] Receiver sensitivity

[ANTHONY CASORSO]

I believe its the first mixer grid. I have mine set up to do this and it works OK. The problem is that the sensitivity is not that good. I made a 7 pole low pass filter that rolls off at 500KHz to kill the BCB junk. I have a 10db amp on it (from KIWA). I  have a switch to disconnect it from the mixer for normal operation. I logged a couple hundred beacons but I can't quite pull in the European megawatters. I get carrier and little else. WWVB comes in loud and clear (I live 50 miles from the transmitter though). Last month I got a selective voltmeter at a swap meet and I have been using that instead.
 
I tried a loop antenna for a while but got tired of having to tune it every time I moved the dial a couple of KHz.
 
Tony> Date: Mon, 2 Feb 2009 15:00:25 -0800> From: drewrailleur807 at yahoo.com> To: r-390 at mailman.qth.net> Subject: Re: [R-390] Receiver sensitivity> > Roger L. Ruszkowski wrote:> > "The R390/A only tunes down to 500 Khz. So while you can dial it down under > 500Khz it is deaf. always has been likely always will be unless you do some very > serious receiver changes. Don't ask me here. Those things are not allowed > under the current administration and were even off limits under past > administrations. Good Fellows do not do those kinds of things to boat anchors. But I > digress."> > Well, it is actually possible to get the R-390A to receive below 500 KC/s without > tearing the radio up. Stick an antenna lead in the RF Deck test point socket for the> third mixer grid. Signals will roll in, though with much trash because of no selectivity> between antenna and mixer. For appropriately enterprising souls, it should be reasonably> easy to cobble together a tuned circuit for use here. Howzabout plugging a tuned loop > antenna into the test point socket?> > Anyone here on the list made it work reasonably well?> > Roger, thank you for the specific and succinct information on measurement of sensitivity.> You are a wealth of information on these radios.> > Drew> > > > ______________________________________________________________> R-390 mailing list> Home: http://mailman.qth.net/mailman/listinfo/r-390> Help: http://mailman.qth.net/mmfaq.htm> Post: mailto:R-390 at mailman.qth.net> > This list hosted by: http://www.qsl.net> Please help support this email list: http://www.qsl.net/donate.html
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