Miracle Whip Antenna
The Miracle Whip compact antenna for the FT-817 is something of a controversial product. Some people love it, some think it is just an expensive dummy load. I think it is a great little antenna, as long as you understand that compromises are necessary in order to have its compact size and convenience of operation.
The main attraction of the FT-817 for me, was the possibilities it presented for making some interesting contacts on HF while out on a walk. However, it becomes considerably less attractive if you have to carry an ATU and tons of wire and aluminium around in your rucksack just to get on the air. So what I really wanted was an antenna that weighed little, occupied little space and made the 817 on HF as easy to operate as a VHF FM handie. The Miracle Whip by Miracle Antenna seemed to be just what I needed.
The Miracle Whip is the smallest and lightest portable HF whip antenna I have seen. It comprises a small plastic box containing a PL-259 plug and a variable matching transformer (the C-VAT) topped by a 57 inch (144 cm) telescopic whip. I think Miracle Antenna missed an opportunity by not making the whip attach to the casing using a jack. This would allow the whip to be removed, for easier carrying, as well as replaced, should it be broken, plus facilitate the attachment of short wires (longer than the whip) for improved performance when the opportunity arises. (Subsequently Miracle Antenna released a product that lets you do just this: the Miracle Ducker.)
I think Miracle Antenna should also consider making a version with an inline BNC connector, as it feels light enough to me that I would be happy to use it on the front panel socket of the 817 for convenient "walkabout" operation. Given the antenna's performance without a counterpoise, this would give the Miracle Whip a major advantage over the competition. It would also facilitate its use with multimode hand-held scanners like the Yaesu VR-500 and the IC-R1, which have a BNC antenna connector on the top. For walkabout use you can, of course, use the whip on the SO-239 socket on the bottom of the radio as normal, but with the whip angled up.
The documentation rightly describes this as a compromise antenna and points out that you shouldn't expect the performance of a full-size dipole. But you knew that, right? The question is, how does it compare with other similar-sized portable whips?
On the air
I compared the Miracle Whip with the ATX Walkabout and I got the distinct impression that the ATX was the better overall performer. The Miracle Whip did seem to have the edge over the ATX on 30 metres, where the whip has to be telescoped down to little over a foot in length to achieve resonance. On 40 metres, the Miracle Whip appeared to be several dB down on the ATX, while on 80 metres it was still quite effective on receive (I copied a VK at 5 2 one night) but no use on transmit. It even receives on 160!
Transmitting on 80 metres was out of the question, as I got a "Hi SWR" warning at every position of the rotary switch. In fairness to Miracle Antenna, they do claim that the MW is "optimised for receive" on the low bands (probably marketing speak for "not much use on transmit".) They also claim that a lower SWR is possible if a quarter wave counterpoise is tried, which I didn't as I did not have that much wire nor the space to deploy it. But frankly, anyone hoping to use such a small whip on the LF bands is going to be in for a disappointment anyway, so this is no great loss.
The documentation states that use of a ground or counterpoise with the MW is "optional" but may yield better results. I spent quite a bit of time trying to determine whether it was worth using a counterpoise or not. Certainly, the addition of a counterpoise changes the optimum tuning point by a couple of click positions of the variable transformer, and it also brought the background noise level up while testing indoors. It increased the strength of many stations too. This testing was done with the 817 running off its battery, so there were no other routes to ground that could have confused the results. When the 817 was powered from a mains supply, the ground provided by the supply seemed to provide an adequate substitute so that counterpoise provided little extra benefit.
When using a counterpoise, the optimum tuning point is sensitive to counterpoise length. I found that bundling together several counterpoises for different bands that had worked fine individually, changed the tuning and prevented a good SWR being found. This is much the same as I have found using counterpoises with other antennas. So, although a counterpoise will probably boost your signal a bit, for convenience (and for receive-only use) it's easier to use the MW without one.
Making contacts
Making contacts using low power with an antenna this short is never going to be easy. From indoors, with the 817 running from a mains PSU and putting out 5 watts, I managed to make several European contacts on 20m during SSB Field Day. Later, on 40 metres, I made two SSB contacts with stations in the Scottish Islands at distances of a few hundred kilometres. The Miracle Whip certainly isn't an expensive dummy load, as some sceptics have suggested.
The Miracle Whip works fine as a 1/4 wave on 2 metres, though the best SWR depends on whether the radio is grounded or not. There's a special VHF position of the tuning knob, and you adjust for "no bars" of SWR by telescoping the whip. Fully-extended, it makes a 3/4 wave at two metres, which has some useful gain. (The original version, which had a shorter, chrome whip, needed a few extra inches of wire clipped to the top to make this possible.)
The Miracle Whip is claimed to work as a 1/4 or 3/4 wave on 70 cm. But even one whip section is too long for a quarter wave on 70cm, while I couldn't get an acceptable SWR using a 3/4 length. For 6 metres you need to add some wire to get a full quarter wave, even with the new version, and so far I haven't tried this.
It's worth noting that the whip can be extended using wire to increase the length and efficiency for HF use too. This is a flexibility not offered by the ATX Walkabout (or the Miracle Whip's UK-made competitor, the Wonder Wand) whose fixed tapped coils can't be adjusted to compensate for the extra length. Adding about 6 feet of wire in an inverted L configuration brought up signals on 40m by a couple of S-points after the C-VAT had been readjusted, but the tuning peak was beyond the transformer's range on 20m.
Conclusion
In my opinion, the easy tune-up of the Miracle Whip, coupled with the fact that it doesn't require a counterpoise, makes it the most convenient portable whip for to use for casual operating with the FT-817. It's so much quicker and easier to set up, you'll use the radio more, and probably make more contacts as a result. A very valuable benefit is that, being continuously tunable, it works well on the broadcast bands too.
The Miracle Whip doesn't work miracles, but for its size it comes pretty darn close.
- If, after reading this, you still aren't sure whether the Miracle Whip is for you, see my Miracle Whip Buyer's Guide.
- For more information, reviews and feedback from other users, subscribe to the Miracle Whip Group at Yahoo Groups.
