Tony Giacometti wrote in
:


I did the measurements in the SSB mode.

This receiver is very quiet with no antenna connected.

I know it is popular to make measurements with no antenna connected
(meaning the antenna jack is left o/c). The measurements are meaningless.

Measurements with a matched load are meaningful, the noise output power
of the receiver is due to the equivalent receiver noise power + the noise
in a matched load.

You will also see discussion of whether receiver noise increases or
decreases when a matched load is disconnected... it varies from receiver
to receiver and it highlights the useless nature of the o/c measurment.

When I tune the preselector for a peak in noise the noise jumps up
noticeably.

What about the AGC setting?


To make a meaningful comparison, the receiver gain must not change
between measurements, so no change in AGC, no change in RF or AF gain,
safest if there is no S meter reading for both measurements.

Turning AGC off doesn't necessarily extend the range of the SSB receiver
where audio output is linearly related to RF input, don't depend on it
unless you have measured its performance.

Owen

Owen Duffy wrote:

Tony Giacometti wrote in
:


I did the measurements in the SSB mode.

This receiver is very quiet with no antenna connected.

I know it is popular to make measurements with no antenna connected
(meaning the antenna jack is left o/c). The measurements are meaningless.

I did put a matched load on the receiver for these tests.


Measurements with a matched load are meaningful, the noise output power
of the receiver is due to the equivalent receiver noise power + the noise
in a matched load.

You will also see discussion of whether receiver noise increases or
decreases when a matched load is disconnected... it varies from receiver
to receiver and it highlights the useless nature of the o/c measurment.

When I tune the preselector for a peak in noise the noise jumps up
noticeably.

What about the AGC setting?


To make a meaningful comparison, the receiver gain must not change
between measurements, so no change in AGC, no change in RF or AF gain,
safest if there is no S meter reading for both measurements.

Turning AGC off doesn't necessarily extend the range of the SSB receiver
where audio output is linearly related to RF input, don't depend on it
unless you have measured its performance.

Owen

I am thinking I should take another look at the receiver and make sure it
does'nt have something strange going on.

I do appreciate your input.

On Nov 17, 7:31 pm, Tony Giacometti wrote:


I am thinking I should take another look at the receiver and make sure it
does'nt have something strange going on.

I do appreciate your input.

You are getting a peak so the loop is tuned.. I doubt the
receiver is the problem, or you wouldn't hear the noise
peak. So it's down to pretty much what Roy just said at this
point. You need to check the nulls. And if the noise
is multiple sources, it can only do one at a time, unless
two are in the same exact direction, or exactly 180 apart.
So it might, or might not do what you want.
The null should be very sharp. Just a slight movement
can cause quite a change in the depth of the null
on a local noise source, so the aim has to be near
perfect for best results.
MK

wrote:

On Nov 17, 7:31 pm, Tony Giacometti wrote:


I am thinking I should take another look at the receiver and make sure it
does'nt have something strange going on.

I do appreciate your input.

You are getting a peak so the loop is tuned.. I doubt the
receiver is the problem, or you wouldn't hear the noise
peak. So it's down to pretty much what Roy just said at this
point. You need to check the nulls. And if the noise
is multiple sources, it can only do one at a time, unless
two are in the same exact direction, or exactly 180 apart.
So it might, or might not do what you want.
The null should be very sharp. Just a slight movement
can cause quite a change in the depth of the null
on a local noise source, so the aim has to be near
perfect for best results.
MK

this is the part that tells me it may be working ok, but the signals even
with the preamp are very low. Some I can't hear at all on the loop but on
the transmitting antenna the signal is there but covered by the S7-9 noise
level.

I have this feeling I don't know what I am supposed to experience from a
working loop.

Anyone have a mp3 file which can show what happens using a loop?

Right now I am hearing very few stations on the loop amd not a one more than
a S5, with an S1 noise level. I hear a couple stations in the SS contest
from the west coast S5 on the loop no noise to be heard, on the
transmitting antenna S6 noise level and the same west coast station S7

I can hear the stations he is working but not well enough to work either on
the loop or the transmitting antenna. The stations he is working are in the
noise and I know they are there.

Does this sound right?

On Nov 18, 4:00 am, Tony Giacometti wrote:


I have this feeling I don't know what I am supposed to experience from a
working loop.

Anyone have a mp3 file which can show what happens using a loop?



Here is one I did in 2002 comparing my 16 inch circle loop
vs my T vertical on the BC band.
-----------------------------------------------------------------------------------------------------

I did a few quick comparisons between a 16 inch loop, and my "T"
vertical, which is about 42 ft tall, with a 120 ft long flat top wire.
It's pretty hot on MW. The radio was my ic-706mk2g. I'll let the
recordings speak for themselves.
You can click on the URl for the sound files, and your media player
"should" bring them right up and start playing. Hopefully anyway...

I did three tests, on three different frequencies, at different times
in the evening. I'm in Houston, and used mainly San Antonio as the
"target" city. "good 200 miles away" I recorded each test. I did
compress the audio greatly to save d/l time, but the audio is still
good enough to tell which is best. The files are pretty small and will
d/l quickly. They were huge files in the original sample rate and
format...I will "narrate" each test, so you will know which antenna
was used, and the exact times I switched. You can use the counter in
the media player to keep track of the time.

Test #1 was at about 7:30 PM on 550 kc.
http://home.comcast.net/~nm5k/mwtest1.mpeg
"Time in seconds"
0-13 -----loop
13-26 -----wire
26-38 -----loop
At 38 seconds I nulled the station, so you can hear the null.
46 -----loop, back pointed to the station
57-69 -----wire
69-end -----loop

Test #2 was at about 8:00 PM on 680 kc.
http://home.comcast.net/~nm5k/mwtest2.mpeg
"Time in seconds"
0-11 -----loop
11-23 -----wire
At 37 seconds I nulled the station
46 -----back pointed to the station
55-67 -----wire
67-end -----loop

Test #3 was at about 9:00 PM on 570 kc. Multiple stations on this
freq...
http://home.comcast.net/~nm5k/mwtest3.mpeg
"Time in seconds"
0-10 ----loop
10-23 ----wire
23-37 ----loop
37-48 ----wire
At 62 seconds, I turn the loop 90 degrees to get a totally different
station.
At 74, I turned back to the first station.
85 ----turned back to 2nd station again
91 ----back to the first


Here is another one on the BC where I turn the loop to null the
station.
http://home.comcast.net/~nm5k/mwtest4.mpeg
At first the station is nulled, and you can hear
a Mexican station in the background. At about 12 seconds,
I turn to the desired station. At 20 seconds I switch to
the T vertical. At 30 seconds I go back to the loop.
At 40 seconds, I null the station again.



Right now I am hearing very few stations on the loop amd not a one more than
a S5, with an S1 noise level. I hear a couple stations in the SS contest
from the west coast S5 on the loop no noise to be heard, on the
transmitting antenna S6 noise level and the same west coast station S7

I can hear the stations he is working but not well enough to work either on
the loop or the transmitting antenna. The stations he is working are in the
noise and I know they are there.

Does this sound right?

Probably so. I haven't found the loops to be that great for pulling
out weak stations on 160m. The success will depend on the level
of noise you are able to cut, vs the strength of the desired station.
This is why I'm playing with beverages a bit out in the country.
I'm not sure how this will pan out, as in general changing the
size of the loop should keep an equal s/n ratio, but some claim
better 160m weak signal use if you use the largest loop you
can manage..

I was able to dig up one 160m file, but it's not for nulling
comparisons.
It's just comparing the general noise received comparing
the full size dipole, vs the loop.
http://home.comcast.net/~nm5k/dpvloop.mpeg
This is pretty much all close NVIS type signals..
Starts on the loop, and switches back and forth.
You can tell which is the loop.. Much quieter
background noise. It takes my AGC a second
to adapt..
It's no good for showing nulls, but it does show
the signal level I get from the small 16 inch loop
using no preamp at all.
None of those clips use a preamp. I've never used
a preamp on small loops yet.. I prefer to avoid a
preamp if possible.. :/

I was going to record a current file nulling line
noise, but I don't have any noise at the moment.. :/
I use the loops for BC band use more than
anything. But both do tune 160m, and I use
it for that band when I want to kill some noise.

MK

wrote:

On Nov 18, 4:00 am, Tony Giacometti wrote:


I have this feeling I don't know what I am supposed to experience from a
working loop.

Anyone have a mp3 file which can show what happens using a loop?



Here is one I did in 2002 comparing my 16 inch circle loop
vs my T vertical on the BC band.
-----------------------------------------------------------------------------------------------------

I did a few quick comparisons between a 16 inch loop, and my "T"
vertical, which is about 42 ft tall, with a 120 ft long flat top wire.
It's pretty hot on MW. The radio was my ic-706mk2g. I'll let the
recordings speak for themselves.
You can click on the URl for the sound files, and your media player
"should" bring them right up and start playing. Hopefully anyway...

I did three tests, on three different frequencies, at different times
in the evening. I'm in Houston, and used mainly San Antonio as the
"target" city. "good 200 miles away" I recorded each test. I did
compress the audio greatly to save d/l time, but the audio is still
good enough to tell which is best. The files are pretty small and will
d/l quickly. They were huge files in the original sample rate and
format...I will "narrate" each test, so you will know which antenna
was used, and the exact times I switched. You can use the counter in
the media player to keep track of the time.

Test #1 was at about 7:30 PM on 550 kc.
http://home.comcast.net/~nm5k/mwtest1.mpeg
"Time in seconds"
0-13 -----loop
13-26 -----wire
26-38 -----loop
At 38 seconds I nulled the station, so you can hear the null.
46 -----loop, back pointed to the station
57-69 -----wire
69-end -----loop

Test #2 was at about 8:00 PM on 680 kc.
http://home.comcast.net/~nm5k/mwtest2.mpeg
"Time in seconds"
0-11 -----loop
11-23 -----wire
At 37 seconds I nulled the station
46 -----back pointed to the station
55-67 -----wire
67-end -----loop

Test #3 was at about 9:00 PM on 570 kc. Multiple stations on this
freq...
http://home.comcast.net/~nm5k/mwtest3.mpeg
"Time in seconds"
0-10 ----loop
10-23 ----wire
23-37 ----loop
37-48 ----wire
At 62 seconds, I turn the loop 90 degrees to get a totally different
station.
At 74, I turned back to the first station.
85 ----turned back to 2nd station again
91 ----back to the first


Here is another one on the BC where I turn the loop to null the
station.
http://home.comcast.net/~nm5k/mwtest4.mpeg
At first the station is nulled, and you can hear
a Mexican station in the background. At about 12 seconds,
I turn to the desired station. At 20 seconds I switch to
the T vertical. At 30 seconds I go back to the loop.
At 40 seconds, I null the station again.



Right now I am hearing very few stations on the loop amd not a one more
than a S5, with an S1 noise level. I hear a couple stations in the SS
contest from the west coast S5 on the loop no noise to be heard, on the
transmitting antenna S6 noise level and the same west coast station S7

I can hear the stations he is working but not well enough to work either
on the loop or the transmitting antenna. The stations he is working are
in the noise and I know they are there.

Does this sound right?

Probably so. I haven't found the loops to be that great for pulling
out weak stations on 160m. The success will depend on the level
of noise you are able to cut, vs the strength of the desired station.
This is why I'm playing with beverages a bit out in the country.
I'm not sure how this will pan out, as in general changing the
size of the loop should keep an equal s/n ratio, but some claim
better 160m weak signal use if you use the largest loop you
can manage..

I was able to dig up one 160m file, but it's not for nulling
comparisons.
It's just comparing the general noise received comparing
the full size dipole, vs the loop.
http://home.comcast.net/~nm5k/dpvloop.mpeg
This is pretty much all close NVIS type signals..
Starts on the loop, and switches back and forth.
You can tell which is the loop.. Much quieter
background noise. It takes my AGC a second
to adapt..
It's no good for showing nulls, but it does show
the signal level I get from the small 16 inch loop
using no preamp at all.
None of those clips use a preamp. I've never used
a preamp on small loops yet.. I prefer to avoid a
preamp if possible.. :/

I was going to record a current file nulling line
noise, but I don't have any noise at the moment.. :/
I use the loops for BC band use more than
anything. But both do tune 160m, and I use
it for that band when I want to kill some noise.

MK


Thank you for the audio clips, the loop is really
working for you.

No preamp!!! WOW!!!

Truly Amazing!