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Lw/ Mv and 160m.. which rx antenna?

 

Hi
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been playing around with ft8 on 160m.. on psk reporter heard in vk etc.. ( when band open.)
tx and rx antenna is a Marconi T. However rx in said directions from here is poor. ( see below.)?
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Live on dartmoor national park ( just,) nice low noise floor. Nice and high (asl)?

I have crossed parallel loops, delay lines and Lz1aq (5551’s) preamps for rx if I wish.
Thing is on 160 the Maroni T beats them..?
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Now I need to state, my garden is on a BIG slope ( Dartmoor) my rx array is 10m below gnd level of house basement.(20m below roof line.) ?My garden slopes to west..
Excellent results from south to north, due to clear take off, but though north/ east to south not so ?good due to antennas below gnd level of house.
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so i ?need to improve rx on 160 towards VK etc.?
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Thinking another singular loop on roof ( have pole already erected. ?Or an short vertical eprobe.?
Have ?never used an eprobe, so no idea of performance..
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Any thoughts???

please see my qrz page for pic of garden to get idea.bottom of garden is to west of house. Bottom of garden ( gnd) is 20m below roof line.
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Simon g0zen?
 

Hi Simon,
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I think it is unlikely that your small loops, in such a low noise environment, will have sufficient "sensitivity" to be constrained buy your local nose floor, which is probably why your Tee seems to perform better. Phasing more small loops my give you the required directively within the space available to you, but I suspect that 8 or more may be required in order to make an appreciable difference.
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The long (ish) wavelength of antennas on 160m, and their interaction with surrounding objects, tends to be relatively stable and predicable, as is propagation.
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I suspect your observations may be being influenced by other factors, such as the underlying geology of the area surrounding your location, and other stuff much further away from the actual antenna.
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E-Probes are problematic, as their unbalanced, high impedance feed, tends to make them a "noise magnet", and you would still have to phase them to obtain the required directively.
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Just my passing thoughts.
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Regards,
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Martin
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On Sun, Mar 23, 2025 at 02:15 AM, Simon wrote:

Any thoughts???
 

Hi Martin

I tend to agree with you. Even with 8 phased loops they will be “below” house gnd level in rhe direction interested in.
Would only be able to mount 1 on house roof level.

Next month am improving the T, the one 25m top wire is being replaced with 3. ( so will look like a mw tx antenna as used by broadcast stations.) This will allow less L on loading coil. “ every bit helps.” Last night worked a good few na and as ru stations on 160m using it..shouldnt complain really.

So unless someone has a plan for a small miracle rx antenna I guess will leave as is..( rx antennas here. Which are 3 crossed parallel loops, each loop made of 4 1m square loops, feeding lz1aq 5551 style preamps and a lz1aq designed 4 way directional delay line box. Thus giving me 2 phased inline loops in 4 directions at any one time.

A flag, k9ay, short vertical etc wont be any better due to where it would be mounted ( down the garden, near my tx antennas and they all appear to need to work against gnd or elevated radials, not practical on the roof!

Thanks for reading Simon g0zen
 

An antenna no one knows about, anymore, it has disappeared from public view and has no supporters, but has allowed stations to work DX they could not have worked without it.
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I speak, of course, of the Waller Flag.
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Here is a presentation from those actually using it:
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Strict attention to detail regarding coax and noise intrusion when constructing the preamps is key, as explained in the presentation.
 

Rather large, plus a fair few negative reviews..ie gone back to a k9.

I do have large mag loop at end of garden. ( total circumference 20m of no joins copper tubing.) My ex London qro loop..will try that outpointing towards Vk.. nothing to lose.
Simon g0zen
 

Hi Simon,
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Unfortunately, I think you are stuck with needing something relatively large.
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I previously mentioned 8 phased small loops, this was to provide sufficient S/N and RDF, so as to be substantially better than your other choices.
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The most useful slide from the YouTube presentation, is probably the one showing the performance of various receive antennas relative to each other.
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I have placed a copy in the group photos section.
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Your Tee and magnetic loop, probably have an RDF of around 5 to 6dB.
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The Waller Flag sits at around 11.5dB, which is similar to a 1000ft Beverage, or an active 8 Square, both of which would require a lot of space to deploy.
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Regards,
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Martin
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On Mon, Mar 24, 2025 at 04:47 PM, Simon wrote:

Rather large,
 

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i really ejoyed the video

i had never thought that two phased loops like the waller flag would have such high RDF number

(i use a k9ay loop here with not tooo bad results but was thinging about build a 2nd one and phase them)

waller flag seems to be fantastic ... (i can not deploy a 1000 feet beverage)

i also was thinking about building 3 loops in a row (cause i have trees in the right direction) and phase all three together but i have to figure out the phasing system ... and what i have seen in the video i maybe should just try two loops with one of them cross connected

dg9bfc sigi

Am 24.03.2025 um 20:15 schrieb Martin - Southwest UK via groups.io:

Hi Simon,
?
Unfortunately, I think you are stuck with needing something relatively large.
?
I previously mentioned 8 phased small loops, this was to provide sufficient S/N and RDF, so as to be substantially better than your other choices.
?
The most useful slide from the YouTube presentation, is probably the one showing the performance of various receive antennas relative to each other.
?
I have placed a copy in the group photos section.
?
?
Your Tee and magnetic loop, probably have an RDF of around 5 to 6dB.
?
The Waller Flag sits at around 11.5dB, which is similar to a 1000ft Beverage, or an active 8 Square, both of which would require a lot of space to deploy.
?
Regards,
?
Martin
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On Mon, Mar 24, 2025 at 04:47 PM, Simon wrote:
Rather large,
 

In addition to the YouTube video about the Waller Flag that Jim posted, there's another one about how to construct one at:

Also,here's a link to a very comprehensive review of low band receiving antennas for small and large lots:

Linda Brodsky, Malverne NY

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Linda Brodsky, Malverne, NY
 

Hi Simon,
It seems to me that you need an antenna that:-
a) is as far away from your TX antennas as possible
b) is small enough to fit in space available
c) is not blocked by your house or pattern affected by the slope
d) has some directivity and covers a reasonable bandwidth
Someone on the group suggested a mini diamond loop and this seems to fit most of the criteria in that it is small enough to mount anywhere and has reaonable directivity and f/b. It could be relay reversed or rotated for more than just one direction.
https://ok1rr.com/antennas/the-w2pm-mini-diamond-receiving-flag/
You would need a high gain low noise preamp. of course)
I was going to suggest a single support DHDL but it would mean installing it down your garden and even a small one takes 50ft or so.
(I used one for years and with 10dB RDF it was nearly as good as my 550/600ft beverages).
The same applies to a mini-4sq..
The Waller Flag is an excellent antenna and is one of the few if any loops that compares in either vert or horiz form in RDF (near 12dB) to a long beverage but down the garden may not be suitable for your location in its vertically polarised form for reasons you have given. N4IS recommends the HWF to be quite high, so in effect needs a large tower .
I wish I had your low noise location!
73
John
 

Sigi

Look at the pi4cc antenna system..( re 3 inline phased.though they are verticals.)

Simon
 

?Hi John and all.

I have room for a dhdl, down the side of garden, would face north of east by abit and be reverseble. But would be REAL CLOSE to the tx antennas. ( though they can be isolated/ detuned , read lifted from gnd on rx if needed.?
But still would be on a slope and again below house at lowest level

Did try the big mag loop last night. Worse signals and same noise floor as the T. However will revisit tonight with the T isolated vis ptt on rx. ( was coupling to tx T, but was late and i had enough at that point. Had just laid 70m of coax to connect it in the dark.)Though not expecting much.

Also will revisit my lz1aq directional array with T isolated ( and mag loop detuned.)

I do have a yccc 9 element array to hand. All made, but no where to fit! ( house was looking at feel though.) which brings me onto below.

Also have room for a 4 square short active vertical setup, each 20m apart. BUT all verticals would be near trees, cables, tx antennas etc etc.. so a no go really.

There is another possibility. However..along shot..a directional array using 3 e probes..
Far end one at bottom of garden mounted on top of Marconi T end mast.
Others at equal height in a triangle formation. this would make them all above gnd level of base of house.
Would use redesigned Lz1aq delay line unit , or even the same unit but mod e probes to use cat 6 cable. However I can see that being alot of work for poor results. Though 4 directions.

Simon g0zen
 

Hi Simon,
If you cant install the mini-loop away from your TX antennas, despite its small size, then another option might be to de-resonate your TX ant and feeder on 160/other bands you operate to make either DHDL or mini-vert 4sq. work down the garden. Unknown result up the slope in direction of house. I remember some years ago that a local got a K9AY working well right underneath his invL next to the house.
A single terminated loop with cardiod pattern like the mini-loop does not have the RDF of a 8 circle or long beverage of course, but it does give more theoretical directivity than a mag. loop. Downside of the mini-loop is the LN preamp it needs for -44dBi but I think you can make these!
73
John
 

Hi John and all

Have been playing with my directional lz1aq array.

First discovered one of loops was in operational.. that didnt help! Sorted now. Also played with delay line settings.

Getting circa 12-18db b/f ratio. ( with tx antennas detuned.) Sensitive enough to copy many Spanish and Portugal mw stations during daylight. ( from Devon.) tx antennas no copy/ very poor copy.

Issue is now noise in n/e direction.

This i suspect is due to top loop placed at top of garden, very close to neighbours house.

So as promising results am going to move loops down garden, thus moving away from noise source ( which by the way the tx antenna ( marconi t) does not hear.)
Also this will allow all loops to be at same height above gnd, at the moment one pair have circa 4m height difference, which also is not helping i suspect.
So now to acquire a scaf pole and 2 bags of postcrete.

Also if does work well to remake the delay line control box/ more loops to add 4 more directions, this is because the beam pattern is tighter than imagined. However this does depend upon my Wife allowing more antennas in garden/ antenna farm.

First to move loops and reevaluate.

Simon g0zen

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