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Re: Antenna amplifier for Beverage and large cardioid loop antennas

Kev Haworth
 

Can someone confirm that Beverage antennas aren't good over saltwater/beaches?


Re: Thanks to Chris #chat

Simon
 

Hi Kev

If you hear any am stateside stations pls list here ..I know Wins is a beacon but any others?

Thanks Simon


Re: Thanks to Chris #chat

Kev Haworth
 

Chris..

Not just that but the MW/LW (similar, I know) frequencies plus the VLF, Anthorn was the strongest I've heard and DCF on 77.5 was a first timer for me.  Along with Mike Ladd on SDRPlay, you've rekindled my love and enjoyment of radio, I only hope I can get WEFAX running now as that is causing me brain ache.


Re: Thanks to Chris #chat

Chris Moulding
 

Hi Kev,

Good to hear that the LAA+ and bias tee board are working well for you.

The bias tee in the SDRPlay receivers are really designed to work with a GPS antenna or similar up on UHF frequencies. It will work OK with the amplifier down to around 500 kHz.

As you have found using the LAA+ with one of our bias tee boards opens it up on the NDB frequencies.

Regards,

Chris


Thanks to Chris #chat

Kev Haworth
 

Had the CCW LAA+ up and running for a few weeks now and been really happy with it. I've been powering it with the Bias Tee from an RSP1A.

Treated myself to the RSPDX and there was a difference, not huge, but definitely better on the lower bands.

I then purchased the Bias Tee Chris sells  and what a difference it has made, within two minutes of setting it all up, I'd clocked two new NDB's and heard RUV from Ei∂ar.

Really looking forward to listening later tonight and hearing what difference it makes to the AM States stations.

All the best

Kev


Re: [mwcircle] Some interesting loop info

Rick Kunath <k9ao@...>
 

If you're referring to the LoG (Loop on Ground) antenna Tom, I can say I have built several and they really do work amazingly well. You wouldn't think so, but that antenna is something worth trying.

I built several of the LoG loops and found that the original 15-foot per side dimension was too short for what I used them for (MW, 160, 80, 40). I never tried a preamp with that 15-foot size so that might be worth doing but I didn't have one laying around. I tried longer loops and even an elevated version 3-feet off the ground but performance with noise was poor. What worked best for me was a loop on the ground 30-feet per side held in place with lawn staples (6-inch by 1-inch wide metal loops, could be made from coat hanger wire). The original was fed through a balun at the feedpoint. I was in a hurry and didn't feed mine that way. I went out searching for suitable wire and wound up getting a 500-foot spool of twisted-pair doorbell wire cheap. It's solid wire, not necessarily ideal and red and white colored, but for a test I went with it. The twisted pair was too hard to unravel into single wires, so I just paralleled the wires for the loop and then used them as twisted pair feedline all the way on the ground back to the shack. It was an all-wrong design, feedline on the ground, through the door, down the hall and to the SDR, but it worked and worked well. I've refined it since that initial test but the feedline is still on the ground to the shack and no balun at the loop. I had fed the SDRplay SDRduo through the high-impedance input initially (so no balun needed), but I have since switched to a Noelec 9:1 balun at the receiver end and feed the SMA input. That balun is modified as Roger Need described to cut the common connection between the primary and secondary windings and is much better isolated for noise. I get a very low noise floor here and good sensitivity on the loop too.

One nice side-effect of having the balun in the shack I discovered later is that I can make a resistance reading on the loop from the shack any time I need to and can determine if there is a break. I have connectored the connection points now using insulated lugs that can be unplugged, so it is easier to isolate the sections. I don't see much trouble with breakage but now and then rolling the mower over it can get the loop open. Likely that wouldn't happen with good thicker stranded wire, and I am going to redo it that way someday. The trouble is the loop refuses to die the way it is now.

I usually use two of the loops separated on opposite sides of the yard by 100 feet or so phased into the SDRduo in manual diversity mode. Both fed to the SMA inputs via Roger Need modified Noelec 9:1 baluns.

The LoG is worth trying and not really visible once you get it installed.

Rick, Kunath, K9AO


Some interesting loop info

Tom Crosbie G6PZZ
 

This blog posting was in a contribution to the IRCA group. I’ve only had time to skim through this but there is info here I’ve not seen before.

Might be of interest to people who like fiddling with loops

 

https://radio-timetraveller.blogspot.com/

 

73

Tom Crosbie G6PZZ

Nr Chesterfield, Derbyshire UK

Lat: 53.167194 Lon:  -1.399204  Maidenhead Locator IO93HE

RX: Lowe HF250, RSPdx, CCW Sentinel 4, Roberts RM50, Radiomobile TR2, Sony CDX-DAB500U Sangean 808

Ant: 15m MLB wire, MTA Vertical, D707 Active,

 


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

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


Re: Has anyone got a current list on mw and lw stations that are currently active?

Simon
 

Hi Tom

Thank you!!

Simon


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

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.


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

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..


Re: Has anyone got a current list on mw and lw stations that are currently active?

Tom Crosbie G6PZZ
 

Simon,

 

Give me half an hour and I’ll send you mine.

 

Tom G6PZZ

 

From: CrossCountryWireless@groups.io <CrossCountryWireless@groups.io> On Behalf Of Simon
Sent: 31 January 2021 21:05
To: CrossCountryWireless@groups.io
Subject: [CrossCountryWireless] Has anyone got a current list on mw and lw stations that are currently active?

 

As above ..for testing of loops..

all i find are out of date stuff..

thanks Simon


Has anyone got a current list on mw and lw stations that are currently active?

Simon
 

As above ..for testing of loops..

all i find are out of date stuff..

thanks Simon


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

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.


Re: Antenna amplifier for Beverage and large cardioid loop antennas

Simon
 

Hi Chris

yes radials..when we moved in we had no neighbours to the left of us..infact both houses were being sold, also the side garden was very empty, plus our rear yarden ( spelt that correctly!) was just  the sand left from an old patio.
i enlisted my daughter at midnight for 3 days  and laid down about 600m plus of radials going from where the loop was to be.( well 1/4 vertical for 40 then.) all bolted to a copper plate...dont tell my current neighbours but their gardens have alot of copper under them!
more went down when we got the patio done..
9 inch disc to cut the ground followed by daughter laying the copper wires!! There are at least  40 plus radials..
each wire 10-20m long..also into side garden..they bend they are straight whatever..
disappears  into the grass very quickly!!tricky to get under the fences though!!

when run against a 1/4 40m vertical ( tx excellent!!! Rx terrible.) mfj259 said 25r ( or so.) ..so a good earth!! Plus the gnd here is sodden clay 12 months a year..

dont tell anyone lol  Simon


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

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.


Re: Antenna amplifier for Beverage and large cardioid loop antennas

Chris Moulding
 

The Loop on the Ground and the Beverage antennas work the same way.

It relies on the incoming wavefront interacting with the ground to tilt the wavefront . This is how a vertically polarised wave can induce a current into a horizontal wire.

Having the wire so close to ground cancels out the horizontally polarised signals leaving weak vertically polarised signals with a very low noise background.

If it's installed over a radial field, seawater or ground with very good conductivity it doesn't work well because there is no or little tilt to the incoming wavefront.

Simon, this is probably why your transmit loop antenna works so well on 160m. With normal ground it would have severe ground losses due to the penetration into the soil. Over saltwater or ground with very good conductivity it will not penetrate the ground so the losses are minimal.

Regards,

Chris


Re: Antenna amplifier for Beverage and large cardioid loop antennas

Simon
 

Jim

Let me know how the log goes if you try one.
I have and it was a total failure..but that may have been due to over many many meters of radials laid out in the side garden..( which it was directly over.) Or i just got it wrong..( probably was late and dark...to keep neighbours off the scent.was a while ago, don’t remember now.)

Considering trying again as so easy to implement..i have a spare ccw loop amp and suitable ferrite ring to wind a matching transformer. Though will be more squashed than ideal..( thin side garden.)

Ideal rx antenna though if can get to work for the nosey neighbour issues..

One wonders what the gnd needs to be to make it work? ( log.) Poor ie like a beverage needs or good like a vertical? My earth is very good..thames basin, always wet clay type soil.( even in mid summer at 2 inches down.)

Simon


Re: Antenna amplifier for Beverage and large cardioid loop antennas

Chris Moulding
 

Hi Jim,

You will be surprised by the Loop on the Ground, I was.

Most radio amateurs think Beverage antennas are only for LF work on 160 and 80m. This is because Beverage's original QST article in 1922 only covers those bands.

It will work well up to 30 MHz. The optimum length is 2 wavelengths but lengths down to 1/4 wavelengths give good results as shown on the web page with a 40m long Beverage on 80m.

A 20m long Beverage running at 330 degrees will give excellent results to North America on 20m and above.

Regards,

Chris


Re: Antenna amplifier for Beverage and large cardioid loop antennas

Jim Smith G0OFE
 

OK, thanks.. interesting. My back garden is about 6m x 6m. Might be worth trying a LoG. Might also be worth trying a ~20m Bog on the path between here and next door, though I'd be restricted to 330°


Jim, Bournemouth, Dorset. IO90BR.
Elad FDM-S2, Airspy HF+, SDRPlay and Funcube Dongle SDR Recievers
8-element OP-DES for Band 2, 8-element LFA for 2m, 3-element LFA for 6m, 20m Windom for HF,. Wellbrook 1530 Loop for LF


On 31/01/2021 11:57, Chris Moulding wrote:
Yes the amplifier works well with the Loop on the Ground antenna.

I did most of the original testing with a Loop on the Ground antenna.

An interesting point I discovered is that the background noise floor of the Loop on the Ground and Beverage antennas is very low often below the noise floor of a sensitive receiver.

Having the amplifier with an isolation transformer and a common mode choke filter built into the amplifier allows the very low signals to be amplified to a useful level.

Regards,

Chris

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