モービル専門、7 & 10MHz CWがメインバンド、時々プチ移動してます


7Mhz 1 pole xtal filter

Few months ago, I have made 7Mhz DC receiver using 1 pole xtal filter.
1 pole xtal filter is effective but not like commercial made multi pole xtal filter.
At field operation with full size DP antenna, it was not able to eliminate QRM (I could hear few stations QRM).
How about spec of 1 pole filter ?
I checked it by KEM-FRA160 which can measure  filter specifications.
800Hz for -6dB range and max-40dB reduction as result.
This looks using for WARC band or high band, 6m maybe useful.

数か月前に製作したクリスタル1個使用の7Mhz DC受信機ですが実際にフィールド運用でフルサイズの逆Vダイポールで受信したら結構QRMがありました

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