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orionreviewcomment [2007/05/20 20:45] (current)
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 +====== Comment on RSGB & ARRL Orion Reviews ======
 +**From the Ten-Tec Reflector July 28, 2006**
 +FYI, ARRL used the optional Ten-Tec #2001 600 Hz filter for their tests per their normal policy of ordering any optional filters closest to their 500 Hz measurement bandwidth. ​ Recall that ARRL did not use the TT #217 500 Hz for the original Orion tests due to IMD problems. ​ Eventually this discovery led to the development of the Inrad #762  600 Hz, which in turn led to the 4-pole filters / front end scheme used in Orion II.  Orion with an Inrad #762 is electrically quite similar to Orion II with the TT #2001.
 +RSGB never orders optional filters for their tests, so the stock 1000 Hz roofing filter was used in both Orion and Orion II tests. ​ However they apparently had a bad 1000 Hz filter in their original Orion test since close-in IMD results using the 2400 Hz filter were better. The 2400 Hz results were the ones RSGB used in the review summary. ​ This time around the 1000 Hz filter had better results for 1 kHz IMD spacing as expected.
 +Bottom line points to remember when comparing these product reviews:
 +  -ARRL used the stock 1000 Hz for Orion.
 +  -ARRL used the optional 600 Hz filter for Orion II.
 +  -RSGB used the stock 2400 Hz filter for Orion.
 +  -RSGB used the stock 1000 Hz for Orion II.
 +  -Orion/762 should have equivalent IMD/BDR to #2.
 +  -Sherwood used the stock 1000 Hz for Orion.
 +  -Sherwood used the optional 600 Hz (for 2 kHz spacing) and 300 Hz (for 1 kHz spacing) for Orion II.
 +  -Sherwood made some anecdotal comments about Orion/762 but never published actual measurements.
 +  -The above are not completely consistent but track well within a few dB of measurement/​sample variation.
 +  -Think mid-90'​s IMD for Orion/762 and Orion II/2001 at 2 kHz spacings.
 +73,  Bill  W4ZV

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