Yu7ef 23cm

necessary phrase... super, magnificent idea..

Category: Yu7ef 23cm

Yu7ef 23cm

InnovAntennas use the very latest in electromagnetic computer design technology in conjunction with Particle Swarm Optimisation methods considered to be the best in optimisation technology today to produce some of the most innovative and high performance antenna solutions available today.

70cm (432 MHz)

Exclusive designs from some of the world's top antenna designers have been turned into professionally built, mechanically excellent antennas with a focus upon being manufactured the right way not the most cost effective way. A number of variants of each model can be produced in order to cater for the real-world requirements of both the commercial and ham customer.

Considerations for light-weight, high wind handling ability, portability and long-term durability mean that no-one mechanical design can deliver a best-of-breed for all scenarios. At InnovAntennas we appreciate this fact and aim to deliver the product you want rather than the product that is most profitable for us. For example, on many HF bands, optimising an antenna for maximum gain is the way to go in most cases but not all provided a near 50 Ohm impedance can be maintained through its bandwidth.

However, on most VHF and all UHF bands, optimising in such a way is detrimental to the receive performance of the antenna and therefore inappropriate for the antenna to be designed this way. This is assuming the antenna needs to receive as well as it does transmit. If you want to be assured of the absolute best performance and antenna stability, along with design consideration for your intended use, InnovAntennas are your only option.

If it is quality and performance you seek then look no further. InnovAntennas provide unparalleled performance from design to build. My Account Orders list Wishlist Checkout. Our Top Products Featured Products. Band Optimised Log Periodic Dipole Add To Wishlist. Add To Compare.

yu7ef 23cm

Multi-Band HF Yagis. OWL-Ultra Xpol. Call for price. Feed Point Sealant. ConductaSeal - Element Joining Paste. HF Dualband Yagis. Call Us Today!I had prepared some standard equipment of the kind, many might have in their shacks:.

yu7ef 23cm

Unfortunately it was rainy outside, the moon close to the sun and a G2 solar storm in progress. When swithing on the transceiver, I noticed some quite massive local QRM.

YO SHF Marathon

As the noise level went up and down and Bernd is one of the big guns on 70 cm, we were able to decode most of his transmissions despite all adversities. Finally we completed the QSO. That was a great job, Bernd! Sometimes you hear words that hurt.

So I forgot Moon Bounce on this band and had fun with other activities, mainly on 23 cm. But the over 30 year old equipment caused more and more problems. So I started collecting parts and modules for a new transverter system covering 23 and 13 cm. On 23 cm it worked fairly, but on 13 cm the drift was a serious problem. After the moon set in Japan, we started:. As he switched his RX from I opened it and found a link to a video he recorded of my recent presentation in Weinheim.

Short version of the lecture with focus on aircraft scatter and ISS bounce. We meet at MEST on the car park at the town hall. There will be a flee market for GHz stuff and the opportunity to test own equipment or to have QSOs with other participants. Full Version with overview of propagation modes, aircraft scatter, ISS bounce and visual moonbounce.

Deutscher Amateur Radio Club e. After giving the presentation in english language in Clonbur, Ireland on August 25ththere will be two more dates in Germany:. For the short version in Weinheim the overview over the classic propagation modes will be left out. Location: Deutscher Amateur-Radio-Club e. As many topics are related to posts on this website, some of them are compiled here. Links to certain other websites can be found in the link list to the right.This antenna is very good compromise for many of those suffering with a limited space for towers and antennas and still want to be QRV on as many bands as possible.

Big advantage of this design is single feed line for both bands. The 4m antenna is actually sleeve fed by inductive coupling with 6m driven element. It is highly recommended to build this antenna with elements fully insulated from the boom since mutual coupling between elements is very strong and adding boom correction might have some unexpected influence. Eventually, element holders such as ones used by Nige G7CNFwho successfully has built and tested this antenna, can be used and in that case boom correction is not required.

For this antenna it is essential to pay special attention to the perfect spacing of the elements since impedances are critical and there is very small margin for errors if correct result is expected. It is obvious that practical results perfectly match calculated specifications and SWR is even better than computer plots. Just as with my other designs, feed impedance is 50 Ohm so only an RFC is required, consisting of 9 turns of cable close wound on a 60 — 80 mm form.

Anyone interested to build other designs please send me mail for available versions and construction details. Antenna with imperial tubing material, used by G7CNF. Antenna with 12mm tubing.HF Antennas. From all of these antennas would be possible to get some more gain with sacrifice of temperature, bandwidth or poor impedance.

All antennas are optimized for pure 50 ohm feed impedance with minimum possible reactance to avoid need for some of specific feed solutions and impedance transformations such as Gamma Match, T-Match, Hairpin etc. This way all antennas have very low internal loss and very good efficiency.

Antennas up to 3 WL are mostly designed as width band designs, having in mind that they can be used as a single antenna for the majority of average users for every day use, by covering — MHz with reasonable SWR. Difference in weight of the antenna with 5 mm wire elements and the one with 8x1 mm tubing is insignificant and one would not get anything but a mechanically weaker antenna.

My recommendation is to use the 8 mm tubing whenever possible for best results. Depending on boom diameter used and type of element mounting, the element lengths from the table need to be corrected accordingly.

Boom correction by DL6WU formula has proven to be reliable over the years and the attached table shows the correction values for wide range of boom sizes commonly used by hams.

With these stacking distances, a 4 yagi bay stacking gain is generally about 5. With every antenna there are also attached single antenna H and E plane radiation patterns. Even though driven element length in tables is given for open dipole, my recommendation is to build antennas with folded dipole due to many advantages compared to open dipole, except simplicity. Special attention should be pointed to spacing measurement, and it always has to be done as shown in the table - cumulative.

Never calculate separate spacings and measure it that way since any measuring errors will accumulate and you will end up with an antenna that is not what has been designed and expected. A large number of these antennas has been built and used by hams with excellent results.

For any further questions and information feel free to contact me on my e-mail :. I would appreciate any feedback about Your experiences and results as well as pictures, to be used for future projects and possible corrections and modifications on existing designs. All these designs are the result of many years' hard work and they represent the intellectual property of the author. Distribution and publishing of these data and information is permitted ONLY for radio-amateur purposes and construction.

Use of these information and data for any commercial purposes is strictly prohibited without the written authorization of the author. Ljubisa Popa.In this article I show how to build up a small but competitive EME antenna and what is important to be successful with a small station.

I chose: 1. The max. Solid aluminium elements with diameter of 6mm to reduce wind load and allow easy screw fixing. Elements mounted on top of the boom with commercial element holders.

What antenna design was first choice? I built 4 x 13 element ZB with a boom 3m 4.

yu7ef 23cm

Stacking distance were 1. With my 4 x ZB yagis and very short cables to the 4-way splitter i could measure 4. This is a very low number for a 4 yagi system on 70 cm. So what is the reason for loosing 3.

How to find out the reason for a low rx performance I was looking for the reason for this low sunnoise and made a simulation of my 4 x ZB compared to 1 x EF Fig 1. In fig. As you can see the 1 x EF has a 5. This is the reason, why the single yagi has a much lower antenna temperature. All the noise from the ground is kept away much better from this antenna. This means with 1 x EF you can copy EME signals with nearly the same signal strength as with the 4 x ZB only because of the clearer pattern.

I build up a single EF Fig. See Fig. The vertical stacking distance was1. As you can see in fig. The suppression for sidelobes 3 to 5 reduces from dB to dB which is no an issue as long as sidelobes are below dB. If you reduce vertical stacking from 1. This is really a very good result for such a small antenna group and gives you the possibility to copy your own CW echoes with about W at antenna under fair conditions in moon perigee.

Its dimension is 1. This group delivers about 8 dB sun noise with SFI 70 and because of the short boom antennas can be mounted at the rear.Like many others I have waited patiently for my IC to arrive, having finally decided to order one in mid I bought an IC three years ago and was delighted at its performance, ease of use and the convenience of the single USB connection for PC control.

My hopes were high for the IC As well as the colour touchscreen display and a very comprehensive settings menus, the transceiver also has real-time spectrum scope and a waterfall display.

2x9 el LFA antenna for EME -- SM6GYBs summer project 2014

The transceiver covers the 2m, 70cm and 23cm bands as standard. It also includes Satellite mode, with any combination of two of the three bands. It features three separate antenna connectors: an SO socket for 2m, and separate N-type connectors for 70 and 23cm.

This is not completely correct, however. In order to cover the 23cm MHz band the architecture incorporates a conventional heterodyne conversion with a to MHz first IF. Direct sampling avoids the limitations of mixing non-linearities and the need for crystal roofing filters which, in turn, can introduce other performance impairments.

One of the most anticipated performance improvements, over conventional superhet superheterodyne based transceivers, was the potential to significantly reduce the noise added to both transmit and receive signals by the often-noisy conversion oscillators in superhet-based receivers and transceivers. The then-necessary VHF first IF crystal roofing filter can exhibit limited performance, putting the remainder of the receiver under greater performance constraints. Read on to discover if this is the radio you have been waiting for.

The front panel features a 4. On the rear panel, Fig. The rear panel is dominated by a rather large cooling fan. While the IC can be used as a single band transceiver on any of the three bands, it can also be used single band but with simultaneous independent receiver Dual Watch on either of the other bands.

But note, it cannot be used with both receivers on the same band. As well as the normal band selection options, the IC can be used as a full duplex transmit and receive simultaneously transceiver on satellite mode. Offset conversion frequency and normal or reverse tracking of the satellite frequencies is catered for in this mode.

The LCD screen can be set to show one band only or both bands simultaneously. Frequency, spectrum display and waterfall, together with receiver S-meter and relative power output meter can also be displayed.

The time, in local or GMT, is also displayed. A Japanese friend told me that the most popular Japanese licence type requires that the MHz output is limited to 10W. These power levels can be adjusted independently on each of the three bands to suit the operator and mode. A useful facility to limit power to a set value is also incorporated. Reports indicate that there is no power spike, unlike many other transceivers that use ALC automatic level control to control output power.

In a direct sampling receiver, a high-speed ADC Analogue to Digital Converter is clocked sampled at a rate at least twice the highest frequency of its coverage.

Since the IC covers up to MHz, you might expect the sampling clock to run at a frequency in excess of MHz. Not so. The sampling frequency, known as the Nyquist frequency, requires that the sampling clock only needs to operate in excess of the highest frequency encountered in the bandwidth of the signal of interest, not the whole bandwidth from DC to maximum frequency.

That is a bandwidth of 30MHz. The sampling clock only needs to operate in excess of 60MHz to meet the Nyquist requirement. Provided the ADC input can process the highest RF frequencies encountered, the sampling clock can operate at moderate frequencies. In the case of the IC the sampling clock operates at This process of sampling the bandwidth rather than the whole DC to maximum signal frequency range is known as bandpass sampling or under sampling.I am preparing the next solar cycle and building a new antenna.

YU7EF has designed fantastic low temperature antennas. Why not to choose the EF antenna? See below for the first results. The antenna length is The external tube length is 4. The internal tube length is 2. To avoid mechanical noise gease is applicated between the two tubes. Two guys support the heavy antenna.

Vibrations have destroyed so many tubing elements. For that reason I have decided to use 10 mm solid elements in a single piece. The weight is more important but it is much more heavy. No tappering nor bad connections. The element bracked is in HDPE natural. The best for HF, poor against UV. An alternative would be HDPE black. The size is x 50 x 12 mm. The two dipole elements still 10 mm solid is isolated by 0.

The H Flex coax cable is choosen for his minimum radius and attenuation. The losses would be around 0. A great advantage of that balun is the HF "stay" inside the coax The disavantage is the frequency dependence and the velocity factor not always as claimed of the coax. Dont use a small plate for that antenna. The plate is fixed to the mast by 4 clamps. You can see the fixation details of the cables. The tube is closed by silicon to reduce the wind noise. The impedance is lower than expected.

Tower, balun or coax influence?


Dull

thoughts on “Yu7ef 23cm

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top