This is TA4AEI, Emirhan, from KM56ju.
I have a QCX working on 30m. Right now it is just being tested with a dummy antenna.
Is there anybody that used that little antenna - Miracle whip antenna? How is its performance?
This antenna is a LOW POWER antenna, les than 20 Watt - for radios like FT817, because of the "NO GROUND"...
It works, and is best at the high end of the HF-bands and 6 meter band.
Its an electrically very small antenna with a matching scheme. The problem is without
a decent ground the performance is mostly converting power to heat. With a ground system
the performance will be poor due to small size.
Keep in mind at 10M a full size whip is abou 8 ft(2.5M), 6M its about 54 inches( under 1.5M).
At those frequencies the antenna is full size and only ground system and height affect
performance. So an efficient antenna for those bands are already small.
When you make an antenna half size the performance reduction is small and it is deemed ok.
But 60 (1.52M) inches at 40M where a quarter wave vertical is about 33ft (10M) that should
be telling. The radiation efficiency with ground is about 1-2% A good mobile whip of 7-8ft
on 40M is about 7% as a comparison.
One use for the Miraclewhip is take the whip off and use the box to feed a 10-20M elevated wire.
in that case the box serves as a antenna matching unit.
3 rules for antennas.
1.For a bigger signal put your antenna higher.
2.If higher is not possible use more wire (or metal aka beams).
3.Failing that keep in mind any antenna is better than a bucket of wire in the shed (not antenna at all).
MiracleWhip is a #3 antenna, generally poor but better than a dummy load though barely so.
On Sat, Apr 14, 2018 at 10:29 am, ajparent1/KB1GMX wrote:
The radiation efficiency with ground is about 1-2%One percent is about 20 dB down, so can use that when considering operating style and goals. I've had contacts that were 60 dB over S9, so with a 20 dB down antenna that's still a strong S9+40dB signal. Or on the other hand go to wsprnet.org and look at the weak signal digital signals and mentally subtract 20 dB from the reported SNRs and you miss out on some interesting signals.
Vince N9NFB EN53ua
I've worked VK foundation stations (10W) from mobile using KNQ7A (about 7W) SSB. Of course
the conditions were exceptional and his antenna was very good. Much of the time no one heard me.
I've also worked people with a grasswire antenna (K3MT) that's a dipole or OCF laying on the ground.
The typical radiation loss is about 12-15Db, but its not hard to setup especially for 160M and it is
exceptionally broadband. On 160 through 20 it was effective and very portable, just lay out 150ft of
wire and a balun on the ground. On 40, even 10W was heard well. Not efficient but effective
and a fast easy setup.
Generally exceptional contacts where the other guy is doing the heavy lifting (tower big beam...) is
not the norm. Its far more interesting to me at HF to be heard at lower power with a good antenna
by someone else distant with a dipole at modest height. by hear I mean a SSB contact where we
were not repeating ourselves several times.
Low power is not an excuse to use a poor antenna as well. It seems if you want to be weak
use a good antenna and a very low power transmitter. Its less effort and less wasting of
electrical energy. So I do suggest using known effective antennas at QRP levels then
going to the territory of lets make it hard.