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 Post subject: Re: A 1947 Magnavox
PostPosted: Feb Mon 08, 2016 10:39 pm 
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Location: Warner Robins, GA
You're welcome.


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 Post subject: Re: A 1947 Magnavox
PostPosted: Mar Thu 17, 2016 6:26 pm 
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I took the receiver back out of the cabinet to do some tweaking on the shortwave end and have managed to get some more sensitivity out of it. It can get a number of European and Asian stations as well as Australia in the early morning. I felt I may have shorted myself getting an older unit as opposed to waiting a long time for a later model. I'm now glad I have this extra feature in addition to a decent amp for my music.

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 Post subject: Re: A 1947 Magnavox
PostPosted: Mar Sun 27, 2016 10:04 pm 
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I ordered a RFI line filter to see if I could bring down some of the noise on AM and shortwave. It has cut about a third of the noise and the shortwave reception is quite good. I had the impression that SW traffic was at a very low ebb. There are several stations that have interesting English services. I was surprised at how well Radio Slovakia and Radio Australia comes in. That old unit has been a real pleasure to listen to.

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 Post subject: Re: A 1947 Magnavox
PostPosted: Mar Mon 28, 2016 1:48 am 
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Very cool. What filter did you use? I may be tempted to install one in my Magnavox CR-198C.

What I have done with all antique radios I have with line to chassis caps or in the case of communications receivers a filter module is to either attach a permanent ground to the center screw of the power outlet or install a three prong grounded power cord. That way the chassis is not at 1/2 line voltage and the radio is grounded. So far I haven't noticed any increased noise or interference doing it like that, but I also am very mindful to check devices for RFI and either buy devices with little to no RFI, take steps to reduce or eliminate the RFI or unplug the device if turning it off isn't enough whenever using my radios.


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 Post subject: Re: A 1947 Magnavox
PostPosted: Apr Sun 24, 2016 8:57 pm 
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I'm sorry, somehow I lost the reply notification. I got a Corcom 10 amp RFI line filter and set it up with a input cord and double outlet. You can find them on Ebay under business and industrial/electrical. The pic shows a 5 amp.


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RFI line filter.jpg
RFI line filter.jpg [ 13.16 KiB | Viewed 2592 times ]

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 Post subject: Re: A 1947 Magnavox
PostPosted: Apr Mon 25, 2016 2:58 am 
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Cool thanks. Might be something worth adding to all my antique radios. Would also provide a way to fuse them as I could install a fuse in the box with the outlet, although I would use a switched outlet which would save the radio's power switch and allow the volume control to always stay at the last used position versus having to remember where it was set when I turn the power on.


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 Post subject: Re: A 1947 Magnavox
PostPosted: Aug Mon 29, 2016 10:16 pm 
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The unit must have gotten some urine on the 15Mhz oscillator trimmer as it couldn't reach a stable adjustment and was severely microphonic. I ordered a trimmer from Surplus Sales to replace it and it improved the reception and it doesn't convey the chassis acoustic noise. I finally added an earth ground to the antenna. I used RG-6 as lead in wire and cut and installed type F terminations and connected a lightning arrestor with the ground to that and the antenna ground on the receiver. Before there was a lot of noise across the shortwave dial. This has cut it quite a bit while retaining it's sensitivity and has brought down a lot of the noise in the broadcast range as well. This old receiver is a lot of fun and really pulls in stations as well. I wouldn't have imagined such a receiver would have such performance. This old thing is as much fun as I had as a kid with a good shortwave radio.

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 Post subject: Re: A 1947 Magnavox
PostPosted: Aug Tue 30, 2016 3:52 pm 
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Very nice.

I love the Magnavox CR-198C I have.

Really pulls in the stations and has excellent audio quality.


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 Post subject: Re: A 1947 Magnavox
PostPosted: Aug Wed 31, 2016 2:26 am 
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Hi TR I have an old pilot chassis that covers am and shortwave has narrow or wide band and a tuned rf as well as 2 stages of if and pulls in stations very well. I also have a zenith console tuner chassis with the same but also has fm stereo. It was not usual to have all that back then. Oh the zenith doesnt have shortwave.


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 Post subject: Re: A 1947 Magnavox
PostPosted: Aug Wed 31, 2016 4:35 am 
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Yes it indeed was odd.

I have a Zenith console made in 1953 that has AM two SW and one SW that is a bandspread of two segments of one of the SW band.

Have yet to see another like it anywhere as the most commonly seen with that style of dial are AM/FM with no SW.


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 Post subject: Re: A 1947 Magnavox
PostPosted: Jan Thu 19, 2017 8:03 pm 
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It appears that, for some reason the RFI filter has failed. While it still passes the working voltage, it is no longer filtering out the heavy amount of RFI my house wiring has.The broadcast bandspread, except for 640 AM, is covered with noise. The filter that failed is rated for 10 amps. I have ordered a 20 amp filter to replace it.

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 Post subject: Re: A 1947 Magnavox
PostPosted: May Thu 02, 2019 6:56 pm 
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The failure was actually the wall power supply that fed my digital cable converter box. I found a better quality supply and that corrected the problem. It was one of a few that I had to replace because of excess RFI.

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