[TenTec] #352 600 Hz Orion roofing filter kit
Bill Tippett
btippett at alum.mit.edu
Thu Apr 1 09:20:36 EST 2004
At 04:21 PM 3/31/04, you wrote:
>Bill: I am curious about the comment you made in the Ten-Tec mailing list:
>
>"P.S. For another $40, Inrad's #352 kit will probably buy you another ~8 dB
>of IMD dynamic range at 1000 Hz spacings."
>
>I can't find an Inrad #352 kit on their Website. Do you mean the Inrad 752
>IF filter (which is $115)?
>
>73,
>Bill NT1Y ex-AA6TT
The #352 is described here:
http://dayton.akorn.net/pipermail/orion/2004-January/000199.html
I just installed the first unit into Orion and it works great. The
advantage is that it overcomes the intermod problems introduced
by the extra amplifier following the 500 and 250 slots. My estimate
is that Orion's already excellent IMD for the 1000 Hz roofing filter,
Preamp Off, will increase from ~85 dB to ~93 dB at 1000 Hz spacings.
I sold my Inrad 400 which was in the 500 slot due to the IMD problems
noted by ARRL, Sherwood Engineering and YT1NT. I don't think Inrad
has their website updated to include this filter kit since it is brand new,
but they should be adding it here in the near future:
http://www.qth.com/inrad/exp_filt.htm
The #352 has basically the same performance curve as the #350,
but is centered on 9001.5 instead of 9000.75 allowing it to work
properly in the 1000 filter slot.
Here are a few construction details which I need to modify
slightly since I have now completed my unit. Bottom line is, copy
W2VJN's layout.
http://users.vnet.net/btippett/inrad_.htm
73, Bill W4ZV
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