Mike
Very interesting signal. I tuned on 3260 and the radar signal was very
strong and let's say unique, two bursts, one narrow band another wide band.
It turns out that I am testing several preamplifiers and the signal on 3260
was Intermodulation coming from the preamplifier. I removed the preamplifier
and listening on the iC7800 the signal is not there.
This is a very serious problem all of us is facing nowadays and it is hard
to even figure I out what is happening.
Two week ago I noticed an intermodulation signal on 1890, I recognized the
AM broadcast program and I was able to identify the two station generating
the intermodulation, I was expecting two local AM BC below 1.8 MHz. for my
surprise both signal was SW, 11,930 MHz and 13,820 MHz , same station Radio
Martã 1890 KHz apart.
With the solar activity peaking the propagation is exceptional good on
6MHz to 9 MHz or 12 MHz and others SW bands. The two station from Radio
Martã was arriving here in Ft Lauderdale with -20 dBm with peaks -10 dBm,
any preamp with 10 db gain will delivery to the radio 0dBm, this is 1 mW
!!!! most radios with IP3 bellow 40 dB cannot handle that level of energy
without distortion and intermodulation.
Most RX antennas have low gain on 160m and requires a preamplifier, however
the same antennas can have some good gain on 12 MHz. With the propagation so
good on SW the broadcasting are causing a lot of problems.
Most of us are not using tunable pre-selector ahead of the preamplifier as
we are used to have on old tubes receivers.
The Radio Martã is not near my house, it is in South Carolina and I'm in
South Florida. Last Sunday I measured s9+60 dB from a BC signal without
preamplifier on 7 315 . this is - 13dBm, with any preamplifier with more
than 10 dB we can send almos 1 mw to the receiver front end.
I try to check 7315 and there are several BC on that frequency form 5 to 250
KW...
This situation with the propagation can last another year or two. Check if
your preamp is not overloading from SW boradcat signals. We need
preselectors or a low pass filter.
See what I found on 7.315 MHz
7315 ADVENTIST WORLD R. 03:00 03:30 1234567 Tigrinya 250
125 KW FIssoudun 46N57 001E59 OFF_AIRMBR
7315 Radio Tamazuj 04:00 04:29 1234567 Sudanese Arabic 250 KW 146
CVASanta Maria di Galeria 42N02 012E18 OFF_AIRPNW/FPU
7315 Radio Dabanga 04:29 05:57 1234567 Sudanese Arabic 250 KW 146
CVASanta Maria di Galeria 42N02 012E18 SIGNAL_STRENGTH_2PNW/FPU
7315 AIR Shillong 06:56 09:31 1234567 Hindi 50 76
INDShillong 25N33 091E56 OFF_AIR
7315 CHINA RADIO INTERNATIONAL 16:00 16:57 1234567 Vietnamese
100 184 CHNKunming 25N10 102E49 OFF_AIR
7315 CHINA RADIO INTERNATIONAL 17:30 18:27 1234567 Chinese 500
300 CHNKunming 25N10 102E49 OFF_AIR
7315 CHINA RADIO INTERNATIONAL 22:00 22:57 1234567 Esperanto
500 294 Kashi-Saibagh 2022 39N21 075E45 OFF_AIR
7315 CNR 2 09:00 16:04 1234567 Chinese 150 ND CHNXian 594
34N23 108E40 OFF_AIR2
7315 CNR 2 20:55 01:00 1234567 Chinese 150 ND CHNXian 594
34N23 108E40 OFF_AIR2=11660
7315 TWR Africa 14:25 14:55 1234567 Portuguese 50 5
SWZManzini 26S19 031E36 OFF_AIR
7315 TWR Africa 14:55 15:10 1234567 Makhuwa 50 5
SWZManzini 26S19 031E36 OFF_AIR
7315 TWR Africa 15:10 15:55 1234567 Lomwe 50 5
SWZManzini 26S19 031E36 OFF_AIR
7315 VOICE OF AMERICA 19:00 20:00 1234567 Kurdish 100 105
DBiblis 49N40 008E30 OFF_AIRIBB/
7315 WHRI CYPRESS 00:00 00:30 12..... English 250 173
USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI CYPRESS 00:30 01:00 .234567 English 250 173
USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI Water of Life Ministries 00:30 01:00 1...... English 250
173 USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI Water of Life Ministries 01:00 01:30 .2..... English 250
173 USACypress Creek 32N40 081W08 OFF_AIR2 a14
7315 WHRI CYPRESS 01:00 02:00 12..... English 250 173
USACypress Creek 32N40 081W08 OFF_AIR2 a14
7315 WHRI CYPRESS 02:00 03:00 1234567 Spanish, English 250
152 USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI CYPRESS 05:30 09:00 1234567 Spanish, English 250
152 USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI CYPRESS 10:00 12:00 .23456. Spanish, English 250
173 USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI Christian Worship Hour 11:00 12:00 1...... English 250
173 USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI Water of Life Ministries 12:00 12:30 1...... English 250
173 USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI CYPRESS 12:00 13:00 1234567 Spanish, English 250
173 USACypress Creek 32N40 081W08 OFF_AIR2 a14
7315 WHRI CYPRESS 20:00 21:00 1234567 English 100 25
USACypress Creek 32N40 081W08 OFF_AIR2 a14
7315 WHRI CYPRESS 21:00 22:00 1.34567 English 100 25
USACypress Creek 32N40 081W08 OFF_AIR2 a14
7315 WHRI CYPRESS 22:00 00:00 1234567 English 250 173
USACypress Creek 32N40 081W08 OFF_AIR1 a14
7315 WHRI Eternal Good News 23:45 00:00 1...... English 250 173
USACypress Creek 32N40 081W08 OFF_AIR
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of
mstangelo@comcast.net
Sent: Thursday, January 15, 2015 9:41 PM
To: Doug Grant
Cc: topband@contesting.com
Subject: Re: Topband: That radar on 1915...
Hearing it on 3260 0240UTC here in New Jersey.
Mike N2MS
----- Original Message -----
From: Doug Grant <dougk1dg@gmail.com>
To: topband@contesting.com
Sent: Thu, 15 Jan 2015 22:24:02 -0000 (UTC)
Subject: Topband: That radar on 1915...
Has anyone heard it recently? I have not been on 160 much since the first of
the year.
I heard it this afternoon on 3250 (it also has been heard on 4400 and 5300
kHz).
Thanks & 73,
Doug
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