[TenTec] IMD Measurements - Yaesu/Inrad vs Orion

[Bill Tippett]

	From ARRL's Product Review of the Inrad Roofing
Filters for the MP family in February QST:

"The real problem shows up during contests when signals
may be every 0.5 kHz (for CW) or every 2 kHz (for SSB
contests)."

So how much improvement is gained at close spacings?
First number is absolute and parenthesis shows changes
relative to unmodified units.

Spacing	ARRL MkV	ARRL MP	RSGB MP	

2 kHz		79 (+10)	71 (+2)		71 (+3)		
1 kHz		69 (+1)		68 (+0)		66 (-1)

(All data from recent ARRL & RSGB reviews of new Inrad mod.)		


Comparable numbers for Orion (stock 1000 vs Inrad #762 filters):

		1000Hz		#762 relative	#762 absolute

2 kHz		89-93 *		+ "6 to 7" **	95-100 ***		
1 kHz		83-85 *		+ "about 10" **	93-95 ***

* ARRL, RSGB and Sherwood.  I used RSGB 2400 Hz results
since inconsistent 1000 Hz results indicate a defective filter IMHO.
** Sherwood's comments (no ARRL or RSGB results available).
***Derived by adding first two columns

Even a stock Orion is still well ahead of modified MP's and the $80
Inrad #762 puts it even farther ahead.  That's just the facts, ma'am.

	Now back to truly important things like microphones, shack
grounds, etc.  BTW what's a shack ground?  I don't use one since I
ground my antennas...not my shack.  All these years I've been very
confused thinking RF was supposed to go into the antenna instead
of the shack!  ;-)

				73 & Merry Christmas to All,

				Bill  W4ZV