[1000mp] S-Meter Adjust Worked and what about the "PIN Diode Mod

[Bill Tippett]

Hi John,

N1JM wrote:
 >Will anything ever top an Orion, HI?

         Yes...an Orion with the Inrad 762 filter!  ;-)
http://users.vnet.net/btippett/inrad_.htm

         Seriously, there is probably no point in
close-spaced IMD dynamic range being much better
than 85-90 dB for most people as W8JI notes below:
http://www.w8ji.com/receiving.htm

The only cases where more DR might be helpful is:

1.  Low-bands during contests or monster pileups.
2.  High-bands if using very high gain antennas (stacks).
3.  Locals within a few miles (especially on 80 or 160).

#1 & #2 are IMD issues caused by multiple close-spaced
(500-1000 Hz) stations that are in the range of >S9+30.
#3 is a BDR issue where 110-120 dB DR may be needed to
reduce front-end overload effects from your S9+60 neighbor.

         For years I used a TS-930S from Colorado and the only
time I ever noticed IMD was during the CQ 160 CW Contest.
I also used an FT-1000MP for about 6 years from here in
NC and the only time I had problems (besides the CQ 160 CW)
was on 10 meters when the band was WIDE OPEN open to Europe.
My 10m stack peaks at ~22 dBi over ground and the band would be
full of close spaced S9+40 to 50 dB signals which created IMD
products within the MP.

         BDR has been a more common problem for me dating from
the late 50's when W4GXB (<1 mile away) was running a Collins
KW-1 to a Telrex Christmas Tree.  My 75A-4 would literally
sound like it was going to jump off the table whenever Tex
came on the same band.  In Colorado, I was 4 miles from K0RF
and 2 miles from W0YK, both of whom ran KW's.  If either of
them came on 160, my TS-930S would also levitate.  Here in
NC, I fortunately only have one neighbor about 2 miles away
who is active on 160.  Even though he only runs 100W to an
inverted-vee, I would know it instantly when using my MP.  So
far, knock on wood, I have never heard any IMD or BDR effects
using Orion (although I once did force some IMD products by
turning an external Beverage preamp up to max gain of 20 dB).

         Bottom line, unless you are in extreme cases like the
above, you will probably never experience IMD or BDR issues
with most of today's better rigs.

                                         73,  Bill  W4ZV