[CQ-Contest] RE:What RF voltage OK at Rx in SO2R?

PETER BARRON ve3pn at igs.net
Tue Sep 25 07:41:37 EDT 2001

Some numbers to consider on this topic
The Delta Loop 80 M apex 72ft is 140ft  from the 20M 5 ele Tower.
The 40M dipole hangs off the Tower  at  66ft  flat to a tree

S9=-70 dBm on HP606 at 3.5 MHz (generator harmonics are probably <<-40 dBc)

20 dBm=100mW

					3.5 MHz		7 MHz		14 MHz
TX ANT	Rx Ant	FUND	2ND	4th
40 M DIPOLE power	20M 5ele	S9	S4	Noise floor
0 dBm		-70dBm	-85dBm	-120dBm
		- 70dBc	-85 dBc	120dBc
20 dBm		S9+18	S8=-76dbm	S5 -82dbm
		-72 dBc	-96dbc	-102dBc
40 M DIPOLE power	80 M Delta[PARA][PARA][PARA]
20 dBm		S9+40	S9	S1 just
		-30 dBm	-70dBm	-120 dBm
		-50dBc	-90dBc	-140dBc

20 M 5 ele	80 M Delta[PARA][PARA][PARA]
20 dBm		S9+18	S5	<S1
		-52dBm	-85 dBm
		-72 dBc	-105 dBc	140dBc

80M Delta	40 M dipole	S6	S3 [PARA]-90 dBm	S2 [PARA]At least
20 dBm		-52 dBm	-110 dBc	-110 dBc

Here clearly  operating on 80 and 20 is not too bad at low power but at 1KW
+60 dBm I would have  well
over S9 on 20 and on 40 1KW would be a real pain S9+36.
(Will measure with the stubs and filters back in and advise)

Peter A Barron
ve3pn at igs.net

I hope typo errors are excused at this time of day , there may be some +/-3
dB error in deltas due
to reading the S meter needle

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