Bantenna

Bantenna sleeve antenna

Bantenna sleeve antennaBantenna Sleeve antenna ALL HF band, ALL modes, CW, SSB, DATA, 100 watts No counterpoise or radials required.

The Bantenna sleeve antenna, launched by David G4YVM, is something a little out of the ordinary, which is why I wanted to take a look. What is it? The antenna is ‘knitted’ into a nylon sleeve, that slips over a 7m fibreglass pole, making for a very quick and easy portable installation.

And because it doesn’t look like an antenna, your neighbours on the campsite won’t have a clue what it is you are up to! The antenna wire is ‘knitted’ into the sleeve, with just a short length protruding at the bottom to connect to the Unun transformer, which comes in a plastic box and with a Velcro tape to attach it to the mast. The connector is a BNC type.

And that, in a nutshell, is the Bantenna!

Bantenna In Use

The selling point of the Bantenna is clearly that it is easy to put up and take down in a portable situation so I wasn’t really expecting anything remarkable by way of performance. But it does claim to be usable on all bands 160 through 6m (really, thinks I?) with a power rating of 100W.

Because it is just a nylon sleeve, the antenna packs up very small although you do need a 7m fibreglass pole to support it. My first attempt was to use a SOTABEAMS Tactical Mini pole, because this collapses down very small, but unfortunately to do so it has more sections than a typical 7m pole and the lower sections were too chunky for the sleeve antenna to slide over them (I should mention that the guidance with the Bantenna is to remove the thin top section of your fibreglass pole, because it will probably damage the nylon sleeve).

Fortunately, I also had a 7m fishing pole (bought for radio use but a fishing pole, for sure, because it still had the ring for the fishing line in the end of the top section!). The Bantenna slid nicely over this (there is a pull strap at the bottom to enable the user to pull the antenna evenly and another at the top for removing it after use).

(I should also mention at this point that the Bantenna normally comes with a suitable fibreglass pole but I had passed on this for the review because I knew I had suitable poles available)

My next challenge was supporting the pole. Bantenna do sell a lightweight guying kit but in my case, trying it out from home, I hammered an old broom handle into the lawn and slid the pole over it.

As I said, the termination is for a BNC connector rather than PL259. This shouldn’t be a problem if you plan to use a Bantenna regularly – make up a suitable coaxial lead with BNC on one end and long enough to reach your car, caravan, tent or whatever.

Checking SWR

First job, before running 100W into the antenna, was to check the SWR on all bands, at low power. While I know that using a Unun does help to hide the ‘true’ SWR of an antenna, I was pleasantly surprised at what I found. My measured results are shown in Table.

Table: Measured SWR

1.8 ………………………………………….3.7

3.5 ………………………………………….1.1

3.8 ………………………………………….1.3

7……………………………………………..1.4

14…………………………………………..1.6

18…………………………………………..1.6

21 …………………………………………..3.7

24…………………………………………..1.6

28 …………………………………………..2.1

29.5 ………………………………………..1.6

50…………………………………………..1.6

In general, as you will see, SWR was 1.75:1 or less on most bands. The exceptions were 1.8 and 21 MHz, where in both cases the SWR was close to 4:1.

This put it outside the tuning range of the ATU in my IC-7300 although well within the tuning range of my Elecraft K3 (which can handle SWRs of up to 10:1). The SWR other users will see will depend to an extent on the length of coax they use to tune it, but I wouldn’t expect it to depart significantly from the figures I was seeing.

Suitably reassured, I tuned around the bands and was pleased to note the strength of received signals, better than I was expecting, recalling as I did a commercial multiband vertical that I had looked at a while ago that had SWRs that were all over the place and that seemed to be little more than a dummy load by way of performance. So, would the Bantenna work in reverse, i.e. on transmit?

My first excursion was on 20m CW, where I raised R125SE (some sort of Russian special event call) first call, followed shortly by a QSO with EA6NB in the Balearics. Given that the Bantenna is designed primarily for portable convenience and certainly not to compete with the typical home station antenna, and that it doesn’t (apparently) require an earth connection, despite being a vertical, this was an encouraging start.

The following day, in the CW Ops CWT event I worked 33 stations in an hour, split between 20 and 40m, in 11 countries, including across to Canada and the mid-west of the USA.

While not a definitive result (depends on band conditions, the stations at the other end, etc), I believe this was a good endorsement of the antenna.

Performance on the other bands was similar – not bad for a relatively short vertical without radials.

Protoypes and preproduction models of the various ununs used

BantennaProduction models, i.e. the one you will receive, will be similar but the box will be lidded! Each unun comes with a fitted velcro strap to fasten it to the mast and with a 4mm bindpost and a well fitted BNC socket.

Why BNC? A good question, and it has been asked. The reason is simple…BNC are so easy to securely fasten to the unun. PL259s can come unscrewed or maybe worse, so bloomin’ tight that with cold fingers they’re a pain.

We like BNC, especially when portable. HOWEVER…if you really, really want a SO239 fitting then it will be fitted, just let us know. Every item we fit is what we think is the proper quality – by which we mean “good”! If you have feedback though and you disagree, do let us us know.

Conclusion

When I am out portable, my preferred solution is usually to use a fibreglass pole to support wire antennas, either a halfwave dipole, or quarter-wave verticals.

This works well but has the limitation that I can only operate one band at a time. The Bantenna is truly a multiband solution, easy to set up and doesn’t obviously look like an antenna. And, in any case, it comes with a fibreglass pole that you can also use for other purposes.

There is a handy video on the Bantenna website, showing how to use the antenna. The Bantenna, complete with Unun and 7m supporting mast costs £125, or £95 without the pole. A three-point guying system is available for £15. Alternative colours are also available – black and ’emergency orange’. Order online: www.bantenna.co.uk

Autor: Don G3XTT

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