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Old October 15th 04, 12:27 PM
Mike
 
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Default Addendum to antenna mount 70'

In my original post of noise in the antenna I should have pointed out
that I have other antennas that I compare it to. The signal is the
same on most antennas, however ie. S-7 on my DX-Ultra has white noise
or not clear, on my DX-A I receive the signal also at S-7 but the
signal is clear....that is to say the DX-ultra has background noise
along with the signal...I think we call this Signal to Noise. Is this
an inherent problem with the DX-Ultra? The best antenna I use for SWL
is a 40M Loop made by Radioworks.com The DX-Ultra is 70' sloped to
about 20' I also use an MFJ-1024 I phase with my K9AY and that works
well. My DX-A is only 35' up but 200' away from the house with 100' of
the coax buried underground(100' above)....with antenna analyzer this
antenna tunes up on 1,660khz with no antenna tuner but is grounded..I
have also found this antenna good on the Tropical Bands with hearing
good signals from Australian Domestics. I am always looking for
improvement. I know about feedline and common mode..this is why I bury
my coax and use isolation Transformers on my beverage antenna. Do you
think a balun on the DX-ultra would create better transfer of signal.
I also use RG-213 which is overkill but perhaps different coax may
decrease the S/N....any suggestions will be well appreciated.
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Old October 15th 04, 09:07 PM
bpnjensen
 
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(Mike) wrote in message . com...
In my original post of noise in the antenna I should have pointed out
that I have other antennas that I compare it to. The signal is the
same on most antennas, however ie. S-7 on my DX-Ultra has white noise
or not clear, on my DX-A I receive the signal also at S-7 but the
signal is clear....that is to say the DX-ultra has background noise
along with the signal...I think we call this Signal to Noise. Is this
an inherent problem with the DX-Ultra? The best antenna I use for SWL
is a 40M Loop made by Radioworks.com The DX-Ultra is 70' sloped to
about 20' I also use an MFJ-1024 I phase with my K9AY and that works
well. My DX-A is only 35' up but 200' away from the house with 100' of
the coax buried underground(100' above)....with antenna analyzer this
antenna tunes up on 1,660khz with no antenna tuner but is grounded..I
have also found this antenna good on the Tropical Bands with hearing
good signals from Australian Domestics. I am always looking for
improvement. I know about feedline and common mode..this is why I bury
my coax and use isolation Transformers on my beverage antenna. Do you
think a balun on the DX-ultra would create better transfer of signal.
I also use RG-213 which is overkill but perhaps different coax may
decrease the S/N....any suggestions will be well appreciated.


Based on what I have read here and elsewhere, you may have too steep a
slope on your DX Ultra. If it truly slopes from 70' to 20', it must
be nearly vertical. I have a DX-Ultra, 88' total length, top about 25
feet and ends about 6 and 10 feet respectively - roughly as suggested
in the instructions - and at my urban QTH I have a fair amount of
noise, but the signal is often huge, and easily overcomes the noise in
most instances. I'd love to get it higher, but it would really be a
challenge on my urban property.

If your antenna is almost vertical, it may be picking up a good deal
of excess artificial noise, and at the same time minimizing the pickup
of signals you want to hear. It sounds like you have some room to
play - may be worthwhile to cut the slope a bit (try cutting it in
half somehow, just to see if your S/N ratio improves).

I have wondered about a matching transformer of some kind on this
antenna too - but I suspect that if it were really necessary, A-D
would offer it as either standard or optional design. Maybe that
arcplug serves in some way to provide that match, in addition to
arresting static...? Or maybe there is something built into the
center hub (it is, after all, designed to mate a dipole to a 50-ohm
lead...).

I wish I had the room, in the clear, for a beverage or another longer
wire ~ always wanted to hear those 2-MHz Aussies well. Heck, I wish
I had room for that K9AY!

Bruce Jensen
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Old October 16th 04, 08:08 AM
RHF
 
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= = = (bpnjensen) wrote in message
= = = . com...
(Mike) wrote in message . com...
In my original post of noise in the antenna I should have pointed out
that I have other antennas that I compare it to. The signal is the
same on most antennas, however ie. S-7 on my DX-Ultra has white noise
or not clear, on my DX-A I receive the signal also at S-7 but the
signal is clear....that is to say the DX-ultra has background noise
along with the signal...I think we call this Signal to Noise. Is this
an inherent problem with the DX-Ultra? The best antenna I use for SWL
is a 40M Loop made by Radioworks.com The DX-Ultra is 70' sloped to
about 20' I also use an MFJ-1024 I phase with my K9AY and that works
well. My DX-A is only 35' up but 200' away from the house with 100' of
the coax buried underground(100' above)....with antenna analyzer this
antenna tunes up on 1,660khz with no antenna tuner but is grounded..I
have also found this antenna good on the Tropical Bands with hearing
good signals from Australian Domestics. I am always looking for
improvement. I know about feedline and common mode..this is why I bury
my coax and use isolation Transformers on my beverage antenna. Do you
think a balun on the DX-ultra would create better transfer of signal.
I also use RG-213 which is overkill but perhaps different coax may
decrease the S/N....any suggestions will be well appreciated.


Based on what I have read here and elsewhere, you may have too steep a
slope on your DX Ultra. If it truly slopes from 70' to 20', it must
be nearly vertical. I have a DX-Ultra, 88' total length, top about 25
feet and ends about 6 and 10 feet respectively - roughly as suggested
in the instructions - and at my urban QTH I have a fair amount of
noise, but the signal is often huge, and easily overcomes the noise in
most instances. I'd love to get it higher, but it would really be a
challenge on my urban property.

If your antenna is almost vertical, it may be picking up a good deal
of excess artificial noise, and at the same time minimizing the pickup
of signals you want to hear. It sounds like you have some room to
play - may be worthwhile to cut the slope a bit (try cutting it in
half somehow, just to see if your S/N ratio improves).

I have wondered about a matching transformer of some kind on this
antenna too - but I suspect that if it were really necessary, A-D
would offer it as either standard or optional design. Maybe that
arcplug serves in some way to provide that match, in addition to
arresting static...? Or maybe there is something built into the
center hub (it is, after all, designed to mate a dipole to a 50-ohm
lead...).

I wish I had the room, in the clear, for a beverage or another longer
wire ~ always wanted to hear those 2-MHz Aussies well. Heck, I wish
I had room for that K9AY!

Bruce Jensen


BJ,

I Agree - Mike may have the Alpha Delta DX Ultra (ADDXU) Antenna
'set' at a to steep vertical angle.

Question - Are there any above or under ground utilities in
the area of the ADDXU Antenna ?

Why not try re-mounting the ADDXU Antenna with the "Center" of the
Antenna 'up' in the Tree (suspended by a rope) at about 30-35-40
Feet with the End-Tips set at 10-15-20 Feet. This will give the
ADDXU Antenna an Apex Angle of about Sixty Degrees (60*).
If the Noise Levels are still the same then shift (rotate) the
End-Tips by Ninety Degrees (90*) [aka: N-S to E-W or vice versa].

Suggest you consider using a Feed-Line Isolator 1:1 Balun (UnUn)
Matching Transformer and Coax "In-Line" Lightening Arrestor with
a Ground Rod near the point where your Coax Cable enters the house.
Mount the Coax "In-Line" Lightening Arrestor directly on the Ground
Rod

iane ~ RHF
..
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