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Reviews Categories | Filters, RF: bandpass, duplexer, lowpass, highpass, RFI/EMI | 4O3A High Power Band Pass Filter Series S Help

Reviews Summary for 4O3A High Power Band Pass Filter Series S
4O3A High Power Band Pass Filter Series S Reviews: 1 Average rating: 5.0/5 MSRP: $470
Description: 4O3A high power band pass filters are build in two different power levels HP 2500W and VHP 4500 W. The decision for having band pass filters after the linear amplifier is simple on that point filters will reduce wide range noise, as good as all harmonics. Also, with filter in antenna line you simplify filter switching system. Filters are very narrow and will prevent interferences, even antennas are very close each other on the same tower.
Once, you have band pass filter after linear amplifier, well designed and reliable, you will forget about all the problems with interferences between the bands and strong harmonics. Six filters and you will not have to care about switching low power filters between the AMP and radio (two sets, at least) and coaxial stubs. Anyhow, in any contest station layout (SO2R, MS, M2) you have to distribute proper antenna on each radio. If filters are in antenna lines, for High Power, then using proper antenna means that proper filter is coming, too. Indicated price is for a single mono-band filter.
Product is in production.
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5B4ADA Rating: 5/5 Aug 25, 2012 00:35 Send this review to a friend
Professionally engineered and desiigned product.  Time owned: 6 to 12 months
During my first T70A operation (CQ WW CW 2010) I could hardly use SO2R due to bad interference from R1. Although larger than the low power multi-band BPFs, one of which I own and had in use at the time, I've decided to purchase 4O3A S series 80-10m filters because 55-75 dB claimed attenuation will not "age" and can easily be inserted into any station antenna line, therefore I considered it as an technological investment for my future operations. The last moment decision followed by a prompt DHL dispatch from Sky Sat Comm and for the T70A 2011 CQ WW CW operation I had a new SO2R addition to my huge, but mobile shack. After assembling all other gadgets at the T70A it took a few minutes to connect 5 filters after the Six Pak 2R antenna switch and vertical antennas mounted around the shack. Except some interference from 160m to 80m (I have not purchased 160m BPF and 80/160m radials are inter-crossing each other), no interference on other bands, which is, despite the low gain antennas used at T70A, visible on increased multiplier score.

I now have 80-10m filters on loan to 4U1GSC station in Brindisi, where all verticals are in very close proximity to each other. Again, no interference at all during the CQ WPX CW contest SO2R operation as 4U1GSC.

It is indeed a good feeling when you transmit on one band and can listen even to the weakest signals on the other band, without getting annoyed by interference. Just ensure all connectors and cables are done properly and you can increase your operating time by full time listening on R2 every time you TX on R 1.

Low budget, smaller size high power filters with bit less attenuation also available for those who may not have antennas in close proximity or for serious DX-peditions, to allow simultaneous operation on multiple bands.

Well engineered and professionally designed product with commercial rather than amateur appearance - my sincere congratulations to the 4O3A team.


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