| M0SVA |
Rating:  |
2010-07-27 | |
| Amazing value for money, grab it if you find it. |
Time Owned: more than 12 months. |
Antenna system consists of:
One large aluminum loop.
Small coupling loop.
Big butterfly capacitor.
Simple, push switch control box.
Interconnecting coax and two-core control cable.
Base for attaching on pole or rotator.
*Small enough to take it for your mobile (portable operations)*
I live in an urban environment, small garden, not enough room for any serious resonant antennas for 20m or lower bands. Also planning permission issues for anything raised above 3m /10ft height as well as renting my property, make things even more challenging for HF.
Got two (second-hand) Capcos a few years ago, one for 80m up and one for 20m to 10m, the smallest model in the Capco series. I didn't get round to testing though till later on.
This review is about the smaller of the two loops the one covering anything from 14 MHz to 30 MHz.
Hung it from a branch of a conifer, about 9 feet from the ground, then connected the coax from the antenna to an antenna analyzer, easily got nil SWR on the digital readout (of the analyzer) by using the *adjustable step* Course/Fine Tuning controls of the Capco controller that moves the plates of the butterfly air variable capacitor.
Connected the antenna to an AOR-7030, and what a joy! Reception could be improved by by rotating the loop and weak signals heard better, became useable and readable.
I then used as a reference antenna a Wellbrook ALA-1530 (active loop antenna broadband, 150kHz-30 MHz). Wellbrook antennas are some of the most respectable RX antennas, exceptionally efficient and quiet.
Both antennas (Capco and Wellbrook) are about 1m in diameter, and were orientated and fixed in the same direction and at the same height when the test was conducted, i.e. East-West.
Used the most challenging band for the physical dimensions of the antenna, the longest wavelength 20m.
Time after time the Capco (when resonance point was found) would (not by much but usefully enough) outperform the Wellbrook when it came to dx propagation beacons (14100 kHz).
Hang it horizontally, you lose your directivity, but you gain omni-directivity, good or bad it depends on the circumstances.
If you don't have the money or the plot to erect towers and expensive Yagis, seriously consider the directivity and sensitivity you can gain with such an antenna. Built quality is simple, yet passing the test of time with flying colours!
Get two of these antennas, then you can have N-S plus E-W reception or anything in between as well as phasing games, now isn't that exciting especially for urban environments or small gardens ?!
It's not enclosed as the MFJ loops, but it's much easier hence to service and inspect from time to time. Importantly, IF you can still find it, it's also much cheaper than a (new) MFJ.
On the flip side, it doesn't look anything as elegant perhaps as an MFJ, if that matters for you or others in your environment. It needs an additional (cheap, any two-core)control cable to rotate the Butterfly capacitor, and it doesn't come with built in cross needle SWR meter.
However, most hams already have an SWR meter which can easily be used for finding the resonance point. Short Wave Listeners though may find the MFJ more practical since it features auto band finding.
Capco, as *all* small transmitting loops, NEEDS retuning every few kilocycles, you can't just "spin the wheel" as with a folded dipole. If this doesn't bother you, you can work any frequency between 14 and 30 MHz, and it's possible even outside the specs, as for example 6 m!
If retuning every few k/c is not your cup of tea, by all means consider a Wellbrook active antenna, which is only for RX though.
All in all I am very happy with the antenna and I expect my Capco to live for many years: NO SENSITIVE electronics whatsoever, and robustly built.
Relevant notes:
1) The Wellbrook is a different class of product, broadband and active antenna covering anything between 150 k/c to 30 M/c with no tuning needed whatsoever, and it does so amazingly well, even at LF dx-ing, let alone "easier bands" such as 80m and 160m! It was used as a reference, just because it's a known top quality loop of similar dimensions, and the only other aluminum small-loop I had.
2) The Capco antenna is sadly no more produced, unfortunately, however every now and then, with some luck, you can still find them in the second hand market.
3) Last but not least, there is some additional input re. this sort of antenna at:
http://www.junksale.co.uk/forums/showthread.php?t=14166 and more at search engines
73 from Dorset,UK
Tim (M0SVA) |
|
| 2E1RDX |
Rating: |
2003-08-14 | |
| very impressed |
Time Owned: 0 to 3 months. |
I have just bought a second hand Capco AMA6 6 band magnetic loop
The loop is 33" across and very well made I have it mounted on a pole abt 15ft from the house and about 9ft high
the loop covers 12,15,17,20,30, and 40m bands
it takes a while to get used to adjusting the control box for a noise peak before final tune up but once you get the hang of it it's a breeze
I have a G5RV up at 35ft one end sloping down to 6ft at the other for comparison tests
the results so far suggest that they are very nr equal in most respects the G5RV just has the edge under marginal or qsb like conditions
my first qso on the loop was with D44TD who had a small pile up but came back to my 2nd call and gave a 5/9 report on 15m ssb
the same night on psk31 on 20m I worked USA,Argentina, Uruguay,Asiatic russia,and loads of europe so that was most pleasing
I believe that this is a great antenna for limited space locations and even on 40m it seems to perform very well
good dx
Ian 2E1RDX |
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