Disclaimer: this web page expresses the personal opinion of the author and is not authorized by any organization. The reader is encouraged to make his own mind based upon the information presented here. All measurement results have been carefully evaluated but stem from a single test session on a single sample of the radio.
The purpose of this test was to gather some information which radios are best suited for MHz operation in large signal environments like VHF contests. Typical signal levels from other high power large antenna stations in such a situation are:. These figures assume that the antennas point to each other which may be true if the interfering stations uses a multi-antenna system and is located in your main direction.
Otherwise signals are typically 20 dB weaker when one of the antennas is pointing completely off the other station. These are real world levels - the author measured at his home site in the Nov. If you plan to use a radio for serious VHF contest operation both RX and TX should allow nearly interference-free operation with levels up to dB ref.
The test shows that there are radios on the market which reach this figure in the RX 50 kHz off the carrier, in the the TX kHz off. This may be just acceptable while at least the TX should be improved. Nevertheless it will result in a strong interference if another station is very closely nearby, and your antennas point to each other. For an interference-free operation in all situations at least dB ref. The IP3 is less important than LO and TX noise performance as there are usually only few strong and very strong signals on MHz so that only few frequencies are corrupted by the resulting intermodulation products.
This situatuion is very different from the situation on the lower HF bands where many stations including broadcast transmitters are present. On the other hand the necessary dynamic range difference between the smallest and the largest signal is bigger on MHz - therefore the need for the best LO noise performance. Radios that are well suited for m CW DX with good close-in large signal behaviour are not necessarily performing well with a transverter on MHz.
This page is on MHz useability only. In the following tables some measurements are summarized which we did starting in early It is not more than a first step, and gives some information which radios must be excluded for serious operation - in fact none are left if you are very serious There are quite some other critical points left like ALC operation, keyclicks, and discrete spurii which must be considered also but could not be evaluated systematically because of the lack of time.
Especially ALC action can cause severe distortion in the transmitter by additional transmitter noise and transient intermodulation at high levels so even radios with good nominal performance in the tables below would need some modification in this point before they reach a similar performance when modulated with voice or CW. The measurement procedures and the test equipment is decribed at the end of this page.
The table shows that there has been a substantial decrease in TX performance in the past decade s. Other use should be prohibited. It shows an increase of the absolute noise power when the output power is decreased only slightly, so at 20 W output the relative TX sideband noise in kHz offset is a poor dB instead of dB at 40 W.
The TSE can be used as RX in a large signal environment like a contest but please do not transmit with this radio. IC and Hohentwiel home construction kit from Germany have low phase noise close to the carrier but do not improve for larger spacing, resulting in mediocre overall performance. The Hohentwiel is still some dB worse than the IC Other radios currently produced have not yet been tested.
Published test results from e. ARRL indicate that their performance may be in the same range. This conversion should be correct as long as noise increase is the limiting factor which is supposed to be true. None of these radios is good for serious VHF operation. The best performance measured yet has the homemade transceiver from DK2GR.
I use an ICE and know why, though being aware of its limitations. It is good enough at least for 23 cm transverter operation. HF Allmode Radios with transverter:.By modern standards it was a small brick but it worked very well, apart from its low battery life.
Similar units were made for HF bands with higher poweron 6m and even 4m. The rig dates from the early s. Although it only produced mW pep this was more than enough to work plenty of locals on SSB and, in lifts and contests some useful DX, much of it when used handheld. It made an excellent little driver for QRP transverters: I made up a set for m, 15m, 10m and 6m and great fun was had. The transverters were out of sight under the desk so the only rig on the desk was the diminutive MX2 which looked all the world like a miniature, miniature HF rig.
Nice having all the controls on the top — convenient for handheld use and neat on a desktop.Most fuel efficient suv philippines 2019
Useful external mic facility when used as a mini-base station. A remarkably good, clean and quiet receiver considering what it was. Limited tuning range: 50kHz on two VXO ranges around the 2m calling frequency. Poor battery life if used with the intended internal 9V PP3 battery pack, even worse if using a rechargeable pack instead. This could be overcome by using an external 9.
The two watt HF and one watt VHF versions introduced in and were produced untila total of 19 years, making the Mizuho MX series handhelds probably the rigs which lasted longest on the market of any ham transceivers ever produced. As a whole, the MX or Pico transceivers were in production for 21 years. Models have been made for every band from 80m up through 2m including 12m and 17m.
Only 30m has been excluded. The milliwatt Mizuho handhelds were successful despite the miniscule power output. They, like most Mizuho products, were sold both as kits and as built and tested radios. Accessories for the early versions of the MX series rigs are now hard to come by. Many of the accessories recently made simply do not fit or work with the early rigs.
This radio has remained in production untiland almost all subsequent Mizuho HTs are based on this model. The volume control was moved to the top of the rig as another rotary knob, and the latching PTT switch found on the milliwatt versions of the rigs was replaced by a more conventional momentary switch.
The mode switch was shifted to the bottom of the rig. Mizuho now had handhelds for the three Japanese novice bands. The line was gradually expanded to include models for all the remaining HF bands except 30 meters. By jCom had picked up the line and sold the MX series as their Pico transceivers. When jCom went out of business Ramsey Electronics bought out and sold off their remaining stock but did not continue to import Mizuho products. Mizuho equipment has not been distributed or sold commercially in the United States or Canada since the mid s.
In the venerable line of monoband handhelds was discontinued. Radios do turn up on the used market all over the world including the U. Mizuho continue to offer repair service and new VXO range crystals. Speaking of accessories, many can still be purchased from a former Mizuho dealer in the U.
The production run sold out quickly. Unfortunately, there are no plans at present for Santec to produce any more handhelds for Mizuho as many parts are simply no longer available or have minimum orders exceeding current demand. Below is a picture of the different looks and brand names sported over the past 22 years by the MX series handhelds. VXO 2 ranges of 50kHz. See More: Link. The sunspot number on that date was Average daily solar flux for the wThat is a lot of bang for the buck!
Getting Started on 2m SSB
The upper right hand photo is a top view of the rig and the lower left hand photo is a shot of the right side vertical board housing the microphone amplifier and audio amplifier stages. Suppose you wanted to build a SSB transceiver, firstly to prove you could do it; but most importantly it must not be complex nor should it cost more than two trips to McDonalds for a family of four.
The real goal is to have something that is portable, lightweight, small in size puts out 5 watts and can do FT-8 as well as SSB. Read on --your prayers have been answered! Oh and you would like a choice of band or perhaps two bands. Forget those 25 cent no name Chinese specials. Mini Circuits pricing sucks big time! Unless you are very experienced and have some decent test gear building a crystal filter involves a lot more than buying 4 crystals on the same frequency.
Trust me buy the filter. Forget Homebrew Filters!!!!!!! I intend to provide a detail of the schematics and an overall discussion of the module integration but the builder will need to do some of the work.
The rig does not build itself. Here are some construction notes and this is a test to see if homebrewers read the information provided. The stack of emails I routinely receive are moot evidence they do not. The next several bullets test your reading and reasoning ability. IF Module Basic. IF Module Relay Wiring. J Module. J Module Switching.
Transmit Driver. Band Pass Filter. Low Pass Filter. Microphone Amp. Audio Amp. Control Wiring Switching Logic. Arduino Wiring, Table of Connections. Miscellaneous Wiring.It took some effort to get enough deviation. Getting deviation was not that difficult. It was difficult to get enough deviation and a accurate carrier frequency. I managed to achieve this by used 2 varicaps parallel. The resulting FM sounds alright on a HF receiver tuned at I tried a different modulator first.
I made a PLL at This chip contains a VCO and a phase detector. FM was made by modulating the loop. It worded but it sounded awful.Nextion printf
I found out that the PLL locked when the loop was open. It had a small catch area. Due to some internal coupling I guess. So I used a second a 74?? It worked. The FM sounded excellent.
However I could not make enough deviation without adding a lot of distortion. I don't know why. I think the concept is good the implementation must be wrong. Maybe the phase detector switches to frequency detector mode for high deviations.Dawa za jino lililotoboka na kuuma
I stopped working at it as it would take too much time to figure it out. If I had succeeded I would have had a HiFi modulator. This would be overkill for a communication transceiver anyway.Determination of solution ph lab report
So I built a modulator using a VXO. Sunday, October 3, minor adjustments. On the web I have found a lock detector circuit for the I may build this someday. For Now I use a TX delay when repeaters are used. A good low noise preamp may help to improve sensitivity. The sensitivity is not bad but my yeasu is better. I hope the sensitivity can reach the same level.
I made a few qso's with it in local radio ralleys. Most reactions were positive. Some have complained that FM deviation is still a bit low. Posted by Luuk at PM No comments:. Friday, June 11, FM deviation increased.
Last night I was able to get more deviation by enlarging the coil in the super vxo. It was difficult to get both a correct center frequency and sufficient deviation. I also removed a transistor that was supposed to work as a varicap. I even forgot it was in.It is impossible. We simply take a lot of old ideas and put them into a sort of mental kaleidoscope.
We give them a turn and they make new and curious combinations. Short Range Wireless Data Communication. HF QRP 1. Phased Direct Conversion Transceiver. CB-band AM Transceiver.
HF SSB6. Shortwave AM Receiver. Two-stages HF Regenerative Receiver. Ten-Tec Shortwave Receiver. Two Regenerative Receivers. Clasic40 Receiver - KK7B. Regenerative FM Receiver. Superregenerative HF Receiver. Superregenerative VHF Receiver. FM Receiver with Strength-meter. Economy Short-Wave Receiver. FM Direct Conversion Receiver. PNP Shortwave Receiver. Simplest Direct Conversion Receiver.
VHF Superregenerative Receiver. Simplest Shortwave Receiver. Medium Wave Receiver for DX.
Mizuho MX2 Handheld SSB/CW Transceiver – 144MHz
FM Receiver with Auto-scan. Active Aircraft AM Receiver. FM Broadcast Superhet Receiver. Public Service FM Receiver.This is not an exhaustive list since there are new radios being introduced every year with additional capability.
FM is the most popular mode primarily due to the wide availability of FM repeaters. These repeaters extend the operating range on VHF and enable low power handheld transceivers to communicate over miles. FM is also used on simplex to make contacts directly without repeaters. The main disadvantage of FM is relatively poor performance when signals are weak, which is where SSB really shines. A weak FM signal can disappear completely into the noise while a comparable SSB signal is still quite readable.
How big of a difference does this really make? Perhaps 10 dB or more, which corresponds to one or two S-units. Put a different way, using SSB instead of FM can be equivalent to having a beam antenna with 10 dB of gain, just by changing modulation types.
So this is a big deal and radio amateurs interested in serious VHF work have naturally chosen SSB as the preferred voice mode. I had just dismantled my 2m yagi antenna and was listening to 2m SSB on a short mobile whip antenna. I figured that with my puny little antenna and only 10 watts of power, there was no way he was going to hear me.
But, what the heck, it was a contest and it would be more points so I gave him a call. The key point here is that this contact would not have happened using FM and was only possible because of SSB.
The SSB portion of the band runs from The 2M SSB calling frequency is One of the realities of 2m SSB operation is that many times, no one is on the air. There is just not that much activity out there, compared to 2m FM. Some amateurs get discouraged, turn off the radio and and miss the thrill of working distant stations during a band opening. It is very common to have stations check in from the bordering states of Wyoming, Nebraska, Kansas, New Mexico or even Oklahoma.
The required equipment for getting started on 2m SSB is pretty basic — a transceiver capable of 2m SSB and a 2m antenna. If you own one of the rigs mentioned above then you are probably ready to go. The 2m antenna you already have is probably vertically polarized since that is what we use for 2m FM, both mobile and base stations. Most omni-directional base station antennas such as those made by Cushcraft, Diamond, Comet, etc. Vertically-polarized stations can work horizontally-polarized stations but there will be a substantial signal loss about 20dB?
If vertical is all you have, then give it a try. If you can get a horizontal antenna, then your results will be much better.We also have a football investment scheme where we unveil the world of football investment and guide you on how to increase your profits immediately. Our investment tracker shows our recent performance as we encourage transparency in football investments. This differs us from all other forecasting platform across the world. Our platform also give punters the heads up by predicting sure football predictions for tomorrow.
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Homebrew 144 MHz transceiver
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