[TenTec] Roofing Filters

[Bill Tippett]

I wrote:

 >1.  Measurements by Sherwood have shown that the 1800 is equivalent
to the 1000 for IMD at moderate spacings (down to 2-5 khz).

         Here are Sherwood's IMD measurements for anyone interested:

IMD at 20/5/2 kHz:

1.8 KHz filter  96/95/93dB
1.0 KHz filter  96/94/93dB

Sources:http://dayton.akorn.net/pipermail/orion/2004-March/000309.html
http://dayton.akorn.net/pipermail/orion/2004-March/000310.html

...and of course the following for the 600 Hz:

"At 5, 10 and 20 kHz, there is no significant (IMD) difference between the
stock 1.0 kHz Ten-Tec filter and the Inrad filter.
At 2 kHz spacing, the improvement is on the order of 6 to 7 dB.
At 1 kHz spacing the improvement is closer to 10 dB."

http://users.vnet.net/btippett/inrad_.htm (private E-mail from Sherwood)

                                         73,  Bill  W4ZV