Scott,
You have already gotten some good inputs on the Ten Tec filters and
Inrad filter for the Orion, but I'll add a little.
I think that during the design stages of the Orion, Ten Tec realized
that many Orion purchasers would already have a 'stock pile', so to
speak, of Ten Tec 6 and 8 pole filters in the 'older' rigs they
already owned. In their consideration for their customer base, they
decided to add two additional filter slots so prior Ten Tec rig
owners could make use of these filters. The 6 and 8 pole IF filters,
obviously, have more insertion loss than the 4-pole roofing filter.
So Ten Tec added an amplifier stage for each of those two optional
filter slots. Unfortunately the added amplifiers also reduced the
receiver performance under controlled bench test conditions. Inrad,
along with the assistance of Bill, W4ZV, (and maybe others) developed
a 4-pole roofing filter with a 600 hz bandwidth. Per Bill's
suggestion, if you removed (or moved) the Orion stock 1.8kc filter,
moved the Orion stock 1.0 kc filter into the 1.8 kc slot, and then
installed the Inrad 600 hz 4-pole filter in the Orion's 1.0 kc slot,
you would improve the close-in test results. The recommendation, at
the time, was to remove your older Ten Tec 6 and 8-poll filters and
just disable those two slots. I personally kept my 250 hz filter
installed and used it for normal rag chews when QRM got really bad,
but not when contesting, as the Inrad 600 hz was an excellent choice
for the bandwidth of a roofing filter for CW use.
With the Orion II, Ten Tec says they have improved the roofing filter
selection pc board design, partially by removing the offending added
amplifier stages for the original stock 6 and 8-pole filters.
Therefore with the Orion II, you should see a decent improvement in
close-in large signal performance for any filter position you select.
Some playing around on your own, using and then disabling the
6/8-pole filter positions would allow you to determine what works
best for you and the manner you operate your radio/station.
Fortunately, you have the choice of what works best for you.
Tommy - W4BQF
At Thursday 10:39 AM 7/28/2005, you wrote:
I have a question for the forum. As a relatively new owner of the
Orion, I am somewhat confused by the discussions on filters. I
bought mine with the optional 288 (1.8 MHz), 285 (500 KHz) and 288
(250 KHz) filters installed at the factory.
I have been reading quite a bit on this site about the Inrad 762
Filter and how it enhances performance ( possibly better than the
Ten-Tec filters).
Am I better off ditching one or more of the above filters and
getting the Inrad? If so, why?
Thanks,
Scott K4VWK
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