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The CCW loop on 6m - some results.

Sean - G4UCJ
 

Hi Chris, and anyone else that is interested,

I’ve been playing around with the active loop for a good few months now – mainly on VHF, with some interesting results.

 

I have to say, it really does work rather well on 50 and 70MHz - far better than I expected if I am honest!

 

A few minutes ago, I was on 6m and the antenna was pointing North-South (ish) and I was hearing EA and CT on FT8 via Sporadic E. I had seen on the DX Cluster that A45XR was being worked in the UK but I couldn’t hear him at all. I turned the antenna (via the ‘Armstrong’ method) so that it was aiming East-West, and immediately decoded A45XR at -13dB! Not a freak ‘one off’ either, I’m getting Kris on most of his TX periods. So it seems that there are directional properties, even at longer distances (the Es cloud for A4 is over Northern Turkey, so definitely a double hop just to get there. The path is about 6600km in total.

 

Yesterday afternoon/evening I was hearing CO, 9Y, YV, PY, W4 and HI – obviously incredible conditions, but some kudos must go to the loop for picking those signals up in the first place.

 

On 4m, last week I heard S0 (Western Sahara) and D41CV, both are a good distance from here and both new DXCC for me on that band. On tropo, I can hear the Cornish beacon GB3MCB pretty much all the time, as well as GB3BUX up in Derbyshire.

 

VHF band II has proved interesting. I’ve not investigated it during an Es opening, but I have no reason to suspect it wouldn’t perform as well as it does on lower frequencies. As regards tropo, I am able to hear a couple of French FM stations on most days – even though I live a good couple of hours drive from the nearest sea. Distance to the F stations is around 430km. Other stations I hear on most days are up to about 200km distant.

 

I can hear the Kent beacon, GB3VHF, on 144.430, every day without fail. GB3MCB in Cornwall comes through with just a slight enhancement in conditions. I can hear repeaters on all bar one of the 2m frequencies (145.7125 is the one I can’t hear a repeater on). If there is a lift on, multiple repeaters are heard on most QRG’s.

 

OK, it’s not as good as a dedicated 2m collinear/white stick or having a yagi for the SSB end, but it’s not a bad compromise!

 

I can even use it for DAB radio, I can hear 59 ‘stations’ under flat conditions – which is actually better than the DAB dipole I had up some months prior. So that’s a top end of about 250MHz before it really does run out of puff. I know at 250MHz, it’s probably a way down on its performance level at lower frequencies, but I’m not complaining!

 

Bring in the HF performance, and you really do have a ‘one size fits all’ antenna, great for when you don’t have the room for several antennas, or antennas for each band.

 

I’ve attached some screen grabs from PSKreporter showing what has been heard here over the past couple of days. There are two grabs that show ‘DX’ and one that zooms in on the UK (copied from the image that shows the Transatlantic stations) , many of the stations received at that kind of distance would be too short for sporadic E and are more likely to have been propagated via other means, i.e. tropo).

 

It is a pity that the new design base unit only has one output instead of the two that was on the older design (Chris explained it was due to the lower gain of the amplifier used now) – two outputs would have made this much, much more flexible for my particular setup. Looks like I’ll have to get saving for a multi-coupler L - one day I’ll get one, which is about the same day I’ll get an Airspy HF+ too ;)   

 

I have no affiliation, etc., with CCW - apart from owning one of their Active Loops.

 

73, Sean – G4UCJ, IO92ma (Buckingham)

 

SDR: SDR-IQ; Airspy; FCD

Antenna: CCW Active loop

 

 

  

Chris Moulding
 

Thanks for posting your results on 50 MHz, Sean.

I often see loop antennas mounted at very low levels but the secret for performance is to mount it high and clear as you have done.

i used to use the prototype loop antenna on a 9m mast to feed 5 SDR-4+ receivers for a WebSDR server. One of them was on 50.150 MHz to monitor 6m conditions in the days before FT-8. One of the local amateurs told me that he often heard stations stronger via my WebSDR server than he could hear direct on his Yagi antenna. Obviously differences in propagation between the different locations but it is a useful antenna for 50 and 70 MHz use.

Regards,

Chris

Sean - G4UCJ
 

Hi Chris,

I’ll say it is a useful antenna! I checked the PSKReporter statistics page and found myself in 2nd place for number of spots in a 24 hour period on 6m. I left it running for about 55 hours as we had the amazing transatlantic conditions over those 2 days. I have yet to confirm the square for one of the stations I heard on a number of occasions, but if it is as listed, then it would be my first ever West Coast on 6m. Looking at the cluster and other sources they all point to N7NR being either in DM03 or DM13, both of which are in California. It’s definitely possible as I heard multiple stations in Texas and a couple on Mexico. On 4m, the farthest heard is D41CV, in Cape Verde.

 

You are right about it needing to be up in the air and clear of objects. Mine is about 6.5m up, but still a good bit below ridge level. That means when ‘beaming’ East, I am going through the roof, or my neighbour’s roof. As there is a chimney breast in there, it is likely to be lined with metal of some kind (lead?), still I seem to get decent tropo results in that direction.

 

Once the Es season is over, I will do some further HF tests, although now that FT8 has entered the scene, 6m is very rarely quiet. Imagine if we had been able to use FT8 during the wild F2 days! Mind you, I’m not sure it would have worked as it was designed for Es, rather than the peculiarities of F2 propagation.

 

I have a 5 ele band 2 yagi in my loft awaiting me to attach the feeder, but I have been so impressed with the CCW loop, I haven’t even bothered to attach the coax to the yagi.

 

Now, I have a technical question regarding the loop:

 

From 50MHz upwards, what polarisation does the loop favour or does it respond to vertical and horizontal polarized signals equally? The reason I ask is so I can decide what, if any, other antennas I need to use.

 

73, and keep up the good work!

 

Sean – G4UCJ    

 

From: CrossCountryWireless@groups.io [mailto:CrossCountryWireless@groups.io] On Behalf Of Chris Moulding
Sent: 04 June 2018 11:18
To: CrossCountryWireless@groups.io
Subject: Re: [CrossCountryWireless] The CCW loop on 6m - some results.

 

Thanks for posting your results on 50 MHz, Sean.

I often see loop antennas mounted at very low levels but the secret for performance is to mount it high and clear as you have done.

i used to use the prototype loop antenna on a 9m mast to feed 5 SDR-4+ receivers for a WebSDR server. One of them was on 50.150 MHz to monitor 6m conditions in the days before FT-8. One of the local amateurs told me that he often heard stations stronger via my WebSDR server than he could hear direct on his Yagi antenna. Obviously differences in propagation between the different locations but it is a useful antenna for 50 and 70 MHz use.

Regards,

Chris

Chris Moulding
 

Due to the size and shape of the loop it is horizontally polarised broadside to the loop and vertically polarised end on to the loop.

I've just checked the antenna gain on 50 MHz mounted at 6.5m using the 4NEC2 antenna modelling tool and over average earth it has a gain of 7.3 dBi  at an angle of 12 degrees. When you consider that it has a masthead pre-amp designed to overcome the inefficiency of a small loop at LF and HF this is why it gives such a good performance on 50 and 70 MHz.

I also looked at 144 MHz and the gain is 4 dBi at 5 degrees so it would still be useful on the 2m band.  

Regards,

Chris