Radiofilters.com

[Spleen]

For you Baltimore City scannists:

I was doing some early Xmas shopping and noticed that the FM 88-108 filters for sale at radiofilters.com are on sale for USD25 until the end of the year. I have used one for quite a while with great results on a Winradio (I think I wrote a mini-review months ago here--hafta search for it later)...

Of special note is that the center frequency is 98.0MHz; does a good job of knocking out WIYY-FM at 97.9MHz...

And no, I don't work for radiofilters.com, I picked one of them up months ago because it was cheaper than the PAR Electronics equivalent, and did the job perfectly well considering the radio I was using it with is plagued with intermod anyway because of the wide band reception capability. When used in conjunction with an old Grove tunable filter set at around 153MHz, makes City scanning a whole lot more productive.

 

[TinEar]

I just took a look at that site you posted Spleen and at the specs for their FM filter. I guess if it works in the city, it would work well out here in Glen Burnie also. I was about to buy the Stridsberg notch filter for the FM radio band just because I know they produce quality products. But there sure is a price difference. Stridsberg wants 85 bucks for theirs versus 25 for this one from radiofilters.com. There is a big difference in the advertised attenuation though - 25db for radiofilters and 60db for Stridsberg. The only thing that worries me is that radiofilters doesn't show their insertion loss. It's less than 1db for the Stridsberg and I can't find the figure anywhere on the radiofilters site. But I guess for 25 bucks it's worth a try. If it doesn't work well it wouldn't be a terrible loss to toss it and then get the Stridsberg. I get a lot of FM generated intermod in the 225-280 portion of the MilAir band.

 

[Spleen]

I can tell you my loss was not detectable in simple tests, but on a wideband radio with a long antenna run that prolly doesn't mean much...I don't have equipment to measure a loss that accurately...if it doesn't move the S-meter, to me that's undetectable...

Even though the notch isn't that deep at the low end, it knocks it down enough to keep those damned college stations and the NPR affiliates out of my way--they actually used to show up in more places than the mid-broadcast band powerhouses, for some reason.

If you pick one up and it has absolutely no effect whatsoever, I'll buy it...I can always use another one for the handheld (helps when using a mag mount antenna), or the old PRO-2030 I take with me to places I don't need trunking capability...

I'm still on the lookout for a comparably priced 152MHz notch filter for pagers...the old tunable Grove filter is ok, but the notch is kinda wide...wipes out all the police action on adjacent frequencies...

Edit: I have an email into him inquiring about tunability to other ranges...I'll find out the insertion loss, too...I'll need to know anyway if I'm going to attempt to use them in a cascade manner...

 

[Audiodave1]

Hey Group,
Shameless plug here on the wrong board but I have a PAR 88-108 filter for sale on Ebay.
See for sale section for links.

Dave Howden

 

[n3bxv]

For those interested in this type of Filter, I purchased the one Dave was selling and it really seems to be doing a great job. I'm getting or at least perceiving much better reception on the CIV and Mil air bands with a lot less backround noise and interference and have been able to adjust the squelch settings on my 780xlts to a lower level... I am however now noticing interference from some EXTREMELY strong pager signals in the 152 mhz range...

Thanks Dave!

 

[Audiodave1]

Hello, Glad you like it.
I had exactly the same problems (50 kw in my backyard) ...too bad I parted with the PAR152 Mhz filter last month.
It works equally well but only goes about 35dB deep but it was more than enough considering I was battling 1Kw @ 152.48 which is about 15db less then the FM station so it worked out the same.

The PAR filters are worth the money.

Dave

 

[Spleen]

Ken is going to ship me one that was widened to cover 75-153MHz with 20 db attenuation...for the sale price, it's at least worth a try at that range, though adjacent pager intermod will still be a factor, I'm guessing; as long as it keeps it down on the other ranges, I'll be happy.