INTRODUCTION
The CCRadioSW (aka Redsun RP-2100) is often mentioned among DXers as a powerful DX radio and in fact it is very sensitive, but it's a little bit behind famous radios like Panasonic RF-2200, CCradio Plus, Superadio 1 or 2 and some others... inspecting this radio I've found that it has a 6 inches ferrite antenna and a poor tracking varactor system (in other words, you can have maximum sensitivity from the AM band low section but the upper frecuencies from 750 Khz and up mistrack (become less sensitive), and viceversa, you need to compromise the end frecuencies to get a so so alignment.
In my quest to get my own grial (To Receive KVNS from Harligen, Tx. USA at NOON INSIDE my house of Veracruz, Mexico (distant about 600 miles) I've been doing some experimentation with varios brands of radios like, Superadio 1,2,3 Panasonic's RF-2200, RF-1150, RF-1170, RF-1180, RF-2600, RF-2800, CCradio, Sony's ICF-5900, ICF-7201 andNONE of them has achieved this goal, some of them receive this station but OUTSIDE the house, so now is the turn for Redsun RP-2100 for a little experimentation.
TRANSPLANTING A 10 INCHES ANTENNA
This was very easy to acomplish, I just took the old 6" one and change it for the 8" (See pict 2) but....The mistrack problem I've mentioned before now got worse !... I had much more signal than before but if I adjust the coil for the traditional 600 Khz the radio becomes deaf past 1100 Khz and if adjust for 1700 Khz (KVNS from Harlingen,Tx) the sensibility in the low channels is severly diminished.
After thinking some days I understood that I need more capacitance in the low channels to track with more precision and minimal in the upper band, normally this is the job of the Varactor Diode VD1 (the black one that is close to the blue preset see pict 4) but apparently this capacitance isn't enough to track so I put a second one in parallel to duplicate the capacitance (I installed underside of the board (see Pict 3) and now the radio track with more precision from 540 to 1700 Khz with some minor variations, in fact the radio now tracks better than before with the old ferrite (Are you listening Redsun Engineers ?...)
Anyway after aligning the radio (570 Khz antenna coils and 1600 Khz the Blue trimmer capacitor pict 4) I was ready to make some tests.... and the result was.... It is now the first radio to receive KVNS INSIDE my house at NOON !!! NO one radio as ever done this, it receive it with 2 bars (Pict 5 shows this). The radio is in general more sensitive across all the band at about 15-20 %
SOME THOUGHTS
I think that I hit the noise floor with this project as the KVNS signal is a very faint one, further I'm going to take this radio to the beach far from the citiy's noises to prove this, and after that NO MORE RADIOS FOR ME !.
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