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Ccw cardioid loop..update from a user of..


Simon
 

Hello

i have tried the loop..as I have stated it was a poor performer..but was it?? 

HOWEVER..i wish to retract this..

reason..

I am using very low input impedance amps on my loops..this is because as a “standard “ good performance loop has a very low impedance..to get best out of loop plus amp impedance must match as close as possible, so one needs a low impedance input amp...ie ccw etc.( very poorly put, sorry.)

now the cardioid loop has a high( ish) impedance compared to my preamps.so poor performance.( only a tiny bit of signal from loop gets to amp.)

now i have added input matching it is quite stunning..
not do hot on 160m..work in progress..( loop to small.)
but on 80m and up it is out doing my endfire crossed loop array..

so ..people try it out..note you may need to increase its size for mw lf operation and change r value..Also may need to alter input matching..( depends upon preamp used.)

stay well ..Simon

ps a rotator would be good too..


Chris Moulding
 

Good to see that the cardioid loop is working well for you, Simon

I've just updated the cardioid loop web page with a link to download a 4NEC2 file with a 2m square cardioid loop design for 160m.

The NEC file is designed so that it can be easily modified in the 4NEC2 editor. The loop size (side), height and resistor can be modified to suit local operating conditions or other frequencies.

The 4NEC2 Optimiser can also be used to optinise the resistor value for best front to back ratio.

The NEC file and an elevation plot of the 160m loop ate at the bottom of the web page:

http://www.crosscountrywireless.net/cardioid_loop_antenna.htm

Regards,

Chris


Tom Seeger
 

Hi. Does the ground wire still attach directly to one terminal of the amplifier, or does it attach to the loop side of the 9:1 transformer?
Tom


Chris Moulding
 

Hi Tom,

The ground wire should attach to the loop side of the 9:1 transformer.

Regards,

Chris


Simon
 

Hi

Well made 2 160m 2m square loops

Tried one out last night, lashed up running one of my preamps with 16:1 transformer..( was to hand .)

As expected it has cardioid pattern.so no nulling of the annoying smpsu to the sw when loop facing nw.

This ment using my pa1sim phaser against a noise loop ( and preamp.)

Didn’t have much testing time as was abit too late to catch more than 1-2mins of vy2ww on 1847 ssb.

Results..could just hear him on 2m card loop.
Nothing on crossed loop single ( also 2m square.)
Nothing on big mag loop
Nothing on endfire loops.

So if it stops snowing will be out today replacing the loops on the endfire with big cardioids.

Results of big cardioid on 80> were inconclusive..reason being was running cardioid loop via pa1sim phaser which has 20db preamp in..it was being overloaded by the increased signal strength from the big loop and preamps..
Later will try with wa1ion phaser ( still need to null smpsu noise.) which has no built in amp, thus removing the amp overload issue.)
If this sorts out the 80m or greater issues ( I expect it will.) then will make the pa1sim amp switchable..( its a much better phaser.so easy to use.)

Simon


Simon
 

Ok

looking quite good..need a few more days to fully test..

wondering however..

the earth wire from loop to gnd..does it need a LOW impedance or not..? I ask as my preamps are cat5 wired..they are connected to the delay line box and my controller. They have the facility to change from x to y direction ( if i had a + type loop up.) so could get 4 directions if i put up 3 loops.
Instead of changing from x to y pattern could very easily use this to control the gnd connection from one side of loop to the other..thus changing direction 180 degrees on both loops..ie nw or se..( also would invert delay line.)
i would just rewire the loop relay from x/y to the gnd control from loop..

??

regards Simon

ps now running loops via wa1ion box no more overload issues on 80> .though it’s horrible to use compared to the pa0sim box ..( altering pa0sim box to have switchable amp.)


Simon
 

Sorry should have said..concerned the relay in gnd crt from loop will cause issues..

simon


Chris Moulding
 

Simon,

Any relay switching the ground connection will have to be very close to the loop.

This will avoid the unswitched length of wire between the loop and re;lay acting as an antenna disturbing the antenna pattern.

Regards,

Chris


Simon
 

Hi Chris

Thank you..1 inch ok then?
Easy to do in preamp box..as thats where existing x / y relay is..

Simon


Simon
 

Hi

watch this space for continued update..in the experiment to see what’s actually possible from a small very  urban house..

with help  from Chris have been playing with phased switchable direction broadside cardioid big loops..looks interesting..listening last night to WINS  in new york on 1010 khz..s9 or so. A good 6db up plus on the crossed parallel loop, plus much less qrm from Europe.( which helps alot!) yes there was qsb, but thats too be expected.( s7 then s9 then s9plus then s7 etc.) 

still much to do..Simon 

ps remember this is from very urban built up london area.not an rf quiet farm in the sticks or similar.


David Cutter
 

I would call that a success and a half.  

Now to tackle that fading...

David G3UNA

On 31 January 2021 at 19:34 Simon <ohhellnotagain@...> wrote:

Hi

watch this space for continued update..in the experiment to see what’s actually possible from a small very  urban house..

with help  from Chris have been playing with phased switchable direction broadside cardioid big loops..looks interesting..listening last night to WINS  in new york on 1010 khz..s9 or so. A good 6db up plus on the crossed parallel loop, plus much less qrm from Europe.( which helps alot!) yes there was qsb, but thats too be expected.( s7 then s9 then s9plus then s7 etc.) 

still much to do..Simon 

ps remember this is from very urban built up london area.not an rf quiet farm in the sticks or similar.


Simon
 
Edited

Yes so would I!

playing around on Lw..as 160 is rather cw busy!

now the broadside cardioid loops are switchable directions..nw or se..

153 România..little on crossed loop.( and really  it is good!) .r5 on broadside cardioid loops..switch to nw..gone..
hopefully WINS or other east coast usa am will appear later to compare f/ b ratio..

simon..


Simon
 

Oh David..Chris gave me a good idea using the broadside loops..to steer the null..building suitable cat5 null steering phaser now..( amps are cat5 feed.) ( to avoid using noise antenna to null out the smpsu issue on 1850khz.) 

that probably will be as far as i can go here..space issues..but so not doing too badly.


Simon
 

At 10pm gmt WINS carrier appeared out of the noise on the cardioid loops.not till 10.30 on the big crossed loop.
by 00.00 happily listening to the news on the cardioid’s
yes could hear on the crossed loop but well down last night compared to the cardioid’s.( More noise and lower signal.)
switching from nw to se WINS disappears on the cardioid’s.
listening of course on ssb, switching sidebands depending upon qrm from very close in ( frequency) stations. Ie WINS i use usb as there is a strong spanish speaking station on 1008 or 1007..

simon


Simon
 

Wondering..just had a listen on mw for stateside am broadcast stations..2am.. broadside big cardioid loops facing nw from london.
atleast 20 odd carriers from usa..( probably many more as stopped looking at 1030khz.) got bored looking as late.)10 plus readable..( some heavy qsb some not so bad..) when i say readable i mean can work out whats being said without too much trouble..the remaining 10 odd only 25% of audio copied ( very very heavy  qsb and qrm from elsewhere.)

is this good or bad or average?
no idea as normally just on 160m and never really attempted to hear usa am broadcast stations..

asking as testing antennas and also may well give good indication when 160 is open..

thanks simon


Tom Crosbie G6PZZ
 

I’m seeing very week carriers but nothing copyable. Hence the need to upgrade the loop.

Tom

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Simon
Sent: 06 February 2021 02:29
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] Ccw cardioid loop..update from a user of..

 

Wondering..just had a listen on mw for stateside am broadcast stations..2am.. broadside big cardioid loops facing nw from london.
atleast 20 odd carriers from usa..( probably many more as stopped looking at 1030khz.) got bored looking as late.)10 plus readable..( some heavy qsb some not so bad..) when i say readable i mean can work out whats being said without too much trouble..the remaining 10 odd only 25% of audio copied ( very very heavy  qsb and qrm from elsewhere.)

is this good or bad or average?
no idea as normally just on 160m and never really attempted to hear usa am broadcast stations..

asking as testing antennas and also may well give good indication when 160 is open..

thanks simon


Simon
 

Hi there..hope you all well??!

update continued.

well..i have been using 2 cardioid 2 m loops ( cat5 feed) with remote direction switching..nw or se.
they were broadside 14m apart.

after much experimenting i have come to the conclusion that the combined noise of both preamps ( both loops phased  together, identical lengths of cat 5 etc) added to the background noise they amplify was GREATER than the extra “ gain” one had in having 2 loops..
ie better sn on single loop than on 2.

so a reworking..

now have one cardioid loop nw or se switching and another ne or sw switching.ALSO they switch from cardioid to “ normal” loops remotely..ie from shack i can go nw, ne, se and sw. OR switch them to normal loops with ne and sw or nw and se.
this i did today. 

testing on 80m...working k2rr vy2 etc on 3790..
on my big mag loop they were hard to hear..noise floor was s7.. they s8 ( they giving me s9 plus!..i guess they running beverages etc.)

on normal loop setting about the same sn but weaker.
on cardioid loop setting....
se ..gone..nothing.
nw ..s7-8 noise s3
sw..s4  noise s3
ne ..s4..noise s4

so..works a treat..out preforming my big mag loop on rx..

similar on 160m aiming at locsl smpsu noise..

beginning to really like the cardioid loops now ironing out any teething issues i had..Very usefull to have a lowish angle of takeoff switchable direction low band rx antenna..

mag loop simon g0zen 


Oyster Town (G0IFS)
 

Hello Simon,
Interesting results. Oddly enough i am just off down the garden to arrange switching of the cardioid loop in a similar way. Comparing cardioid loop with 400ft loop on ground it just has the edge-----most of the time. So log will be rolled up this morning and the relays used to compare aerials will be switching direction and from cardioid to normal.
Question---have you tried shared apex loops?


Chris Moulding
 

Good to hear that after all your work you've found the optimum cardioid loop setup for your location.

Regarding the switching arrangements I can see that you can easily change the antenna direction by swapping the ground connection from one amplifier terminal to the other.

To go back to simple loop configuration have you just disconnected the ground completely and use the loop with it's termination resistor?

Regards,

Chris


Simon
 

Hi

First no have not tried the shared apex loop..lack of space in the direction i would want to face it..

Re the switching of the cardioid loop

Cat5 controlled.no coax.
Cat5 has common mode choke at preamp end.all control lines grounded to earth stake via 100nf at common mode choke.
Relay 1 switches the earth from one side of loop to the other..gnd switched.
Relay 2 switches the gnd on/off.again gnd switched.
Relay 3 activities with relay 2.it is mounted in separate box at resistor.it bypasses resistor( or not, depending upon normal loop or cardioid.) wiring to relay 3 is also cat5 with 100uh and 100nf at each end ( preamp and resistor.)

Using 9:1 matching transformer at loop to preamp.

This i may also make switchable in/ out..BUT so far it does not seem to upset normal loop operation leaving it in, so may just leave it.

Yet to fully test on 160m and mw..was having too much fun using it on 80m dx last night and ran out of time.(besides best dx on 160 seems to be gray line at moment, and was far too late for that.)

On 80m made all the difference between hearing N/A over the noise or not..