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Countries

27.6%UNITED KINGDOM UNITED KINGDOM
23.6%UNITED STATES UNITED STATES
5.7%GERMANY GERMANY
4.2%ITALY ITALY
3.2%POLAND POLAND
3.2%SPAIN SPAIN
3%FRANCE FRANCE
2.2%NETHERLANDS NETHERLANDS
1.7%BELGIUM BELGIUM
1.6%FINLAND FINLAND
1.6%AUSTRALIA AUSTRALIA
1.6%JAPAN JAPAN
1.4%CANADA CANADA
1.3%HUNGARY HUNGARY
1.2%CZECH REPUBLIC CZECH REPUBLIC
1.1%ROMANIA ROMANIA
0.9%SWEDEN SWEDEN
0.9%SLOVAKIA SLOVAKIA
0.9%RUSSIAN FEDERATION RUSSIAN FEDERATION
0.9%AUSTRIA AUSTRIA

Visitors

Today:  8
Total:  6844





Viliam Petrík


23.04.2009 09:34:58
I have tried to use a special receive receive antenna in the CQ WPX Contest. Team OM0A has run M2 category and beverage antennas was the last antenna that we have built on Friday’s evening. Luckily I was on the 80m band during the morning’s openning to Carribean and North America.

It’s a huge difference between inv.Vee and beverage antenna. Even though our location has a very low noise, the main improvement was in the attenuation of local stations. Not only stations from other directions, but also closest stations from OK and DL. Heavy QRM gone and I could copy sigs from stateside. Some of them was in the same strenght as on inv.Vee antenna, some was louder.

I break pile-up and start hunting W stations. Unbeliveble hour! Comparing to other stations from Slovakia, our result on 80m is better! I love beverage antenna.

How to built it?




23.11.2008 14:40:27
I have finished the beverage antenna preamplifier. The 9:1 transformer is based on the W8JI’s recommodations. It is wound on the tree binocular ferrite cores BN73-202. I was wondering how the SWR is. When terminated with 450 ohms there is no significiant return power, when terminated with 470 ohms the SWR rise to 1:1,1. Perfect!

The schematic diagram of preamplifier looks very simple – two LC circuits and MMIC. There is much more to do with adjusting bandpass filter and fiting the circuit in the shielted box and all in the waterproof box.

The circuit was later improved with a LED diode which is indicating if the current is flowing to the box or not. Output plug is standard PL.




11.11.2008 07:33:24
The beverage antenna project for 80m has begun. This weekend I have build simple preamplifier with MSA monolithic microwave integrated circuit. The gain is around 8db and amplifier compression -1dB is at 19dBm point. The gain should be not greater due overloading receiver. Yesterday I have measured input bandpass filter which I got from my another project - RX for 80m. Due the possibility of detuning in various temperatures I have set greater bandwidth. The passband is now 3,52 - 3,92MHz.

Not easy to found non-inductive resistors for beverage. It's terminating resistor with value around 450 Ohms. After several minutes I found suitable resistor in my box. Today I would like to wind transformer 1:9 and move filter on new PCB.

Later I will buy two waterproof plastic boxes and fit all inside them. Probably on the end of November I try beverage antenna on the Air.



24.09.2008 11:59:29
Topband with its wavelenght 160m is not very easy band. Dimensons of antennas are extensive. For MW9W contest crew I have prepared simple but effective antenna for 160m – the Inverted L antenna. It’s based on the material DK5WL „Invisible“ DX Antenna for the Low Bands.

The Inverted L antenna is simple quaterwave antenna with a shape of inverted L letter. Most transmitted energy is vertically polarized. That’s an advantage for DX contacts.

Jirka OK5IM is selling fibreglass poles with total height 12,5m. I bought two and prove the antenna in the IARU HF Championship with impressive result. Try it too!







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