The best low pass filter available... says Bencher. Also suitable for high power - up to 1.5kW in FM, 5 kW peak. 1.8 to 30MHz, very steep skirts., attenuation approx. 80 dB.
Kenwood low pass filter for shortwave reduces TVI and BCI. The filter is inderted between transceiver and antenna, s close to the transceiver as possible. Impedance 50 Ω, insertion loss ca. 0.5dB, upper cut off frequency 30MHz, max. power 1kW PEP.
In some cases traditional low pass filters have a limited effect on TVI and BCI. Usually because these interferences are not caused by harmonics but by common mode currents on the outer shield of the feed line, these currents are not affected by low pass filters.
To solve these problems a new kind of filter is available - the common mode filter for 1.8 to 70MHz, which is inserted into the feedline just as a low pass, as close to the transceiver as possible. Common mode suppression up to 250MHz and up to 50dB.
Two versions are available: max. 250W or max. 5000W power load (key down!), insertion loss max. 0.1dB.
In Japan, a land with very high amateur radio density and lot's of TVI situations, already a quarter million of these filters have been sold and used successfully. Connectors 2x PL or 2x N.
For convenient connection to the transceiver, add to your order:
for the 250W version a PL angle 90° with plugs (male) on both sides Order No. 42022.01;
for the 5000W version order a PL angle adaptor (M/F, Order No. 42022) and a dual PL connector (M/M, Order No. 42024)
Common mode filter - low cost version by MFJ. Frequency range 1.8 - 30 MHz, size 13x5cm, PL jacks, max. 200W PEP.
Fight interferences with toroidal ferrites. Just wrap the cables of the affected device once or several times around the toroid, close it, ready. Suitable for all types of cables. Optimal frequency range 0.5 to 200 MHz.
For all kind of round cables (Datac ables, coax cable, rotor control etc.). Very good suited for fighting interference of computers (keyboard or USB cable)... some PCs just can't stand the HF power.
Depending on the situation to be installed at either end of the cable. A selecteion of ferrite cores is a must for every DXpedition!
Of course you can try to build a common mode filter with these cores, but you will need several cores on the cable (at least for shortwave). If you are looking for ready made common mode filters, check our article 11368, right here.
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