Cross Country Wireless Experimenter's Antenna UnUn
The Experimenters Antenna UnUn is a multi-purpose antenna balun for HF or HF/VHF antenna experimentation.
It contains a multi-tap autotransformer and a common mode choke in the same box.
All inputs and outputs are brought out to a BNC female socket and terminals consisting of stainless steel bolts and wing nuts.
The input to the common mode choke is a BNC female socket with 50 ohm output from the common mode choke appearing between the common ground terminal and 50 ohm output terminal.
A wire link typically connects to the 50 ohm input of the autotransformer.
Three output terminals from the autotransformer give output ratios of 4:1, 9:1 and 49:1.
The autotransformer can also be wired in reverse with a 50 ohm input between the 4:1 and the common ground terminals to make a 1:4 ratio giving a 12.5 ohm impedance between the ground and the terminal marked "50 ohm input".
Specifications:
Frequency range (HF version): 3.5 to 30 MHz
Frequency range (HF/VHF version): 14 to 60 MHz
Input impedance: 50 ohms
Power rating: 150 W SSB/CW , 100 W FT-8
Output impedance: 50 ohms (common mode choke output), 200, 450, 2450 ohms
Weight: 274 gm (9.6 oz)
Experimenter's Antenna UnUn connectors: Six M6 stainless steel threaded studs and BNC female
We use eBay for our individual customers as they look after the import tax and fees involved in international transactions.
The eBay listing is here.
If the eBay listing is sold out we have a regular stock situation post on the Cross Country Wireless Groups.IO forum..
We also announce new batches of our products on the Groups.IO forum.
For our professional and commercial customers we now have a Wise.com account so we can accept bank transfers in local currencies worldwide.
Contact us for a quotation.
Here are links to various antennas that can be built with the Experimenter's Antenna UnUn:
Beverage's paper for the A.I.E.E in 1922. The 56 page report that covers the Beverage antenna development in full
Beverage's 9 page article for QST.
Beverage's 1921 original patent for the Wave antenna
Beverage's 1923 patent covering additional Wave antenna developments
Link to the KK5JY page on the Loop on Ground antenna
Many radio amateurs think that the Flag antenna was originally designed in the 1980s.
The original design was patented by Harold.H.Beverage of RCA back in 1941 with the original patent application made in 1938.
Yes, it's the same man who designed the Beverage Wave antenna back in 1921.
Click here for a copy of Harold Beverage's patent.
Earl Cunningham, K6SE independently developed the Flag antenna through antenna modelling various antennas in the 1990s. He was probably unaware of Beverage's previous work.
Here is a link to an excellent article on Flag, Pennant and Ewe antennas by W8JI
As the Flag and Pennant antennas designed by K6SE were intended for the 160 and 80m amateur bands Neil Kazaross developed the Kaz antenna for medium wave DXing.
Here is a link to an article on Kaz and SuperKaz antennas by John Bryant
One version of the Flag antenna modelled by Earl Cunningham, K6SE was later built by W2PM and called the Mini-Flag.
This used a diamond loop of wire with sides of 5 feet or 1.5 m. The feed point was at one corner with a 680 ohm resistor at the opposite feed point.
We used a version of this during the testing of the Flag Antenna Amplifier.
As the antenna is small in size the received signal level is low and it is a good test of the amplifier and it's internal common mode choke.
We expect to have a video demonstrating the amplifier with this antenna soon.
Here's a YouTube video with more details of the UnUn:
Contact Chris Moulding via info@crosscountrywireless.net