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Reviews Categories | Antennas: HF Portable (not mobile) | G4TPH magnetic loop antennas Help


Reviews Summary for G4TPH magnetic loop antennas
Reviews: 7 Average rating: 3.9/5 MSRP: $79 Brit.pounds
Description: Portable magnetic loop antennas.
Product is in production.
More info: http://www.G4TPH.com
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G4JNW Rating: 5/5 Nov 7, 2017 11:37 Send this review to a friend
Worth the money  Time owned: 0 to 3 months
I was having severe QRM with my wire antennas but they did tx well after a lot of thought i decided on a loop but i wanted one that would go into the loft and be within reach of my pension so no mega expensive loops. My eyes are not the best and dexterity isn't as good these days so did not want to build one. I wasn't expecting much hence using it as Rx antenna against my wire.
I have to say it performed much better than i expected. Signals are down 1 S point on my external wires but NO noise.
Its important to put the spring washer between the bars. Also i tightened the screws really tight seeing as it will be mounted permanently. I made up a cross of 2 inch plastic tubing and fastened the loop to it and mounted it in a TV type rotator. I do tune it with my antenna analyser but you could do it by ear. The only improvement i could see is rather than an up down switch to tune the capacitor, some sort of tune meter but im sure that would ad quite a bit to the price.
 
N1SFX Rating: 4/5 Feb 12, 2017 09:55 Send this review to a friend
Great begining concept for experimentation  Time owned: more than 12 months
It is what it is, Tom G4TPH has been very responsive in giving advice on the product.
Yes, the aluminum bars are a PITA to keep together and as magloop principals go the loop should has minimal resistance.
The Toroid is a good beginning and the motorized tuning cap is a great concept.

At the price point it can not be beat, Change the coax to LMR400 - Add SO 238's to the tuning case ans use solid copper wire from SO238's - for QRP the tuning cap is Ok but needs to be changed to handle more power.

Not bashing any reviews. I am just opening a window for improvement suggestions on a good basic concept project.

I have mine mounted horizontally in the loft of my shed ~ 10 feet above ground, Stock I get it to cover just at the bottom of 40 to just above the 12 meter band by removing two aluminum bars.

I got it based on the price, the remote tuning feature and the power rating - Did not want to spend the cash on MFJ loop.Reading up on magloops I knew the G4TPH would need improvements but, I still got it anyway.
 
W4OP Rating: 1/5 Sep 1, 2016 08:18 Send this review to a friend
Very inefficient  Time owned: 0 to 3 months
I was able to borrow one of these antennas for testing.
What intrigued me was the 100W claim and no retuning across the band. Both claims (while true) are counterintuitive of what should be the case with an efficient small transmitting loop. The more efficient the loop, the narrower the bandwidth and for a given capacitor plate to rotor spacing, the less the power rating of the antenna.
The answer to how the antenna can handle 100W and such a wide bandwidth is:
1. The the loss in all of the aluminum joints
2. The use of aluminum as opposed to copper
3. The use of a flat strip as opposed to a round tube (current crowding of a flat radiator makes it less efficient than the same circumference of a tubular radiator
4.Likely some loss in the ferrite transformer.

The variable cap spacing used should be capable of around 20W maximum if the loop were at all efficient on 40M. So the math tells me that 80W is being lost in I squared R and toroid heating and the capacitor then can handle the remaining 20W.

Comparison of a similar diameter copper tube loop showed this antenna to be over 10dB below the copper tube antenna on 40M. To put it another way, 10W from the copper tube loop would radiate the same signal as 100W from the G4TPH on 40M.

The copper tube loop had a 2:1 bandwidth on 40M of 14KHz, demonstrating decent efficiency for such a small loop.

Dale W4OP


 
W8LV Rating: 5/5 Aug 14, 2015 13:03 Send this review to a friend
It Actually Works!  Time owned: more than 12 months
I bought one directly at Dayton. the last one in his suitcase, I believe in 2009 (or was it 2010?) as I recall.
The one I have is Manual for 40 metres. It works!
Is it a full length dipole at a half a wavelength above ground?
Of course not! But you can stick it in a (non metallic coated) window, or hang it up ANYWHERE, and it WILL get you QSOs!
You won't find a more portable antenna that works, and I am suprised, year after year, that we don't see this in everybody's Ham Arsenal of Antennas.
A puzzlement to me!
 
G4YVM Rating: 2/5 Aug 14, 2015 09:45 Send this review to a friend
Poorly constructed and designed  Time owned: 0 to 3 months
I was really looking forward to using this aerial on holiday. Alas, it really wasn't up to my expectations. In theory it's a good idea, in practice...ten pieces of aluminium held together in a circle with one bolt at each end is never going to work. One needs to fasten the nuts and bolts very tight to both prevent slippage and keep a sensible Q. Without tools this was impossible. I don't carry tools when out portable. Consequently the aerial never retained it's shape. I also found the through bolts on the capacitor box working loose. This is a minor niggle but shouldn't happen.

I will try to find fixes for these issues, but all in all, the aerial is disappointing.
 
M3UHQ Rating: 5/5 Jan 17, 2013 07:43 Send this review to a friend
Fantastic bit of Kit  Time owned: 0 to 3 months
At the time of writing this I have not had a lot of time to do a full review but for what it's worth The Mag Loop is a Fantastic Antenna, I simply put it all together with the supplied instructions and hung it up in my Window, this QTH is right in the middle of the city, I was delighted to hear a Station from the North Pole: NL7HH on my Yaesu FT-817ND, I am looking forward to using this antenna in the summer months when on holiday in the UK and when my new ham shack is finished (being built in the next week).

I had the antenna within two days of ordering, Tom is a great guy and has helped me a lot. 73
 
W7KB Rating: 5/5 Dec 1, 2011 09:44 Send this review to a friend
Superb portable magloop antenna  Time owned: 0 to 3 months
I was recently looking for a portable magnetic loop antenna online and came across G4TPH magloop antennas.I contacted the owner,Tom G4TPH and he quickly emailed me back with all the info.requested about his antennas.I ordered the ML-MK20II loop and exactly one week later,I received a 4"X4.5"X20" box shipped via air parcel from England.In short time I was able to assemble the loop and placed it atop a tripod mounted PVC pipe about 7-8' above ground.Using my antenna analyzer,I was able to tune all bands quite easily from 20-10 meters with a SWR of 1.5-1 or better on all bands.Once tuned to the center of any band of intended use,the SWR will remain the same over the entire length of the band or with only a slight rise in SWR readings.With 10 watts,I made only made a few contacts due to unfavorable band conditions.The next day,I used 35 watts of power and received a 5/7 signal report into Florida and a 5/9 report into Michigan on 20 meters from my Arizona location.The antennas are rated at 35 watts,but for safety sake on early tests I ran them at that power level or less.These loop antennas hear better than any other antenna I have ever used and are ideal for portable operations with no ground or counterpoise required.Along with the ML-20MKII for 20-10 meters,Tom also offers the ML-40MKII for use on 40-15 meters and the ML-6-2 for 6 and 2 meter use.In addition to these fine products,Tom also offers excellent customer support service with his magloop antennas.73 Dennis W7KB.
 


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