Introduction OM0A Band filters in the contest

Band filters in the contest

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Department No. 1 - 80m, 20m, 10m

Posting to multiple zones from one unit puts very high demands on durability radio receiver. When using high output and an unfortunate coincidence may be up to the destruction of the receiver input circuit.

Coaxial filters are proven by stump K2TR. I výhodou per jednoduchá realizovateľnosť a efektívnosť, as determined by a measurement OK1WVK http://www.sweb.cz/ok1vwk/koaxf.htm . For contestové OM0A need not produce the filters to 80 m and 20 m:

Filtre to pripájajú that výstup transceiveru, or. Output stage most easily using the PL-T connectors. The quality of the coaxial cable used has an impact not only on loss, but also the suppression of unwanted frequencies. Suitable cable and also for higher performance is RG-213.

An example of manufacturing a filter for 80 meters band: at the end of cable mount connector. Calculate the length of the formula štvrťvlnného pahýľa 75 x / F (eg. 75 x 0.66 / 3.68MHz = 13.45m). As you leave the reserve 20 cm, that we should shorten the. Since the connector thus charged 13.65m, odrežeme end of the cable and short circuit (properly begin). Filter connect through the PSF meter installation and meter can be charged via an artificial load. In the 80 m band filter may affect the value of PSF and the meter must show the full power. If the device can transmit outside the amateur radio bands, we can at prelaďovaní to see more bands than decreasing power meter for artificial load. We reduced the measurement performance, since the PSF is very high (if we have a pad on the power, recommend use). In the 40 m band so we can find the frequency, which is printed with a maximum, which verifies the basic setup for the band. Where it differs from the desired, pahýľa adjust the length measurement and repeat. When will differ from the calculated length (13.45m, see. more), We computed after adjusting the stump and cut-off factor - to facilitate the setting up filters for more bandwidth. The end of the cable then seal duct tape or stretch the teplomzmšťujúcu bužírku.

K2TR koaxiálny filter pre pásmo 80m
K2TR coaxial filter for 80 meters band, suppresses 40 m, 20m, 15m and 10 m band
K2TR koaxiálny filter pre pásmo 20m
K2TR coaxial filter for 20 meters band, 40 m and 15 m suppresses band, suppresses the second dock 10 meters band