SOTABEAMS 2m BANDPASS FILTER

OK, I live within a mile of Olivers Mount a 7KW FM and Freeview TV mast on the outskirts of Scarborough. I bought this filter to test a theory that the mast was dragging down 2m reception at my home QTH. I had previously tried activating the transmitter site as a HEMA summit but failed due to RX swamping causing me to hear nothing. I took delivery of the filter on Saturday. On Sunday I hooked up a Baofeng UV9R and tuned into the mast FM broadcast frequency 95.5. On WFM the signal could be received with a wet finger on the antenna socket it was so strong. I put the 9R onto a loft mounted slim Jim and the signal was so strong as to be breaking through several hundred KHZ adjacent. I then put the filter inline and tried again. There was nothing! Not even when tuned to 95.5 could I hear a single thing. I determine by experimentation that the rejection of broadcast FM is very very good. I think dialled up GB7RW a local repeater about 15 miles away. This repeater is usually scratchy at my QTH despite being able to open it. With the filter inline the RX from the repeater was a full 2 S points up and now breaks my squelch! Although I got the filter for SOTA I can see it becoming a permanent addition to the shack setup to. Wonderful, well made and works!

3 Replies to “SOTABEAMS 2m BANDPASS FILTER”

  1. I agree that a good filter can block out over running interference from strong FM stations. I am looking at getting something to use while on mobile. Here near Houston, Texas USA we have a multitude of very strong FM signals that tend to become annoying at the least. Luckily at my QTH I am in a quiet country setting with little interference, but this summer I do plan on traveling a bit so I want to be prepared with the right equipment beforehand. Thank you for the good idea!

    1. Hey Bud, good to see you and thanks for the comments. I am sure we worked each other on 2E0WWV-L the other week? I have since made the filter a permanent feature of my radio backpack with great results. Another up side of having one is its ability to basically bolt on a bit of filtering to budget radios! My BF UV9R loves this filter 😀 73 Scot

      1. Yes that was me! I have enjoyed reading and studying your blog so far. Unfortunately we don’t have any peaks nearby here for any SOTA work, but I am very interested in QRP in general. Keep up the good work!
        73 – Bud KI5OMM

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