Receiver FT-817 is made according to the classical scheme. The HF signal from the antenna connector enters the low-pass filter (there is no band-pass filter at the transceiver), then there is an attenuator (ATT), after it there is a switchable UHF on the bipolar transistor (IPO-ON). Further, the signal through an additional low-pass filter goes to the balanced mixer from the assembly on four field-effect transistors. After the mixer is the first IF filter frequency
On VHF, separate low-pass and high-pass filters are used for the 145 and 436 MHz bands. Further, the signal path is similar. The only range for which the signal flow in the cascades is different from the rest is 76 – 108 MHz.
The transmitter is made quite simple, a single-band signal is formed in the classical way, using a balanced modulator. Some transceiver nodes are used for both receiving and transmitting. The main feature of the transmitter circuitry is the power amplifier, which is used in both HF and VHF bands. Of course, this worsens its efficiency, but it saves space on the board. The transmitter consumes about 2A at maximum power (5W).
The power supply to the transceiver can be supplied in two ways, through the external connector and through the battery compartment. Both methods have slight differences. When powered by internal elements FBA-28 or FNB-85, part of the voltage (
Carefully looking at the circuit, we can conclude that the transceiver should not be powered more than 14V. The manual says up to 16V, but this is an undesirable limit, since many electrolytic capacitors on the boards are rated for 16V. Hence the conclusion: the safe voltage for FT-817 should be considered 10 – 12V, and the maximum
Due to the fact that the transceiver can ‘open up’ and get a continuous range of HF, it becomes possible to use the FT-817 (in emergency situations) to communicate with rescue services.
As soon as you bought the transceiver and brought it home, the first thing you have to do is rewrite all the settings in the engineering menu! This is important because the transceiver does not provide for their recovery, after a failure or after someone has climbed it.
To do this, turn off the transceiver, simultaneously press the A B C buttons and turn on the power without releasing them. The transceiver will make a plaintive sound and you will see the first item on the engineering menu on the display. Take a notebook pen and rewrite all values. It is enough to write the item number and its parameter. For example, 01 – 69, 02 – 66, and so on. To move to the next item, turn the SEL knob. Do not touch the other knobs, so as not to knock down the value!
ATTENTION! You can not copy the settings in the engineering menu of one transceiver to another. The values of all items are strictly individual for each device. All the factory settings of your transceiver, it is desirable to double-check the devices according to the method of service manual.
After this action, press F so that the transceiver returns to normal operation. Sheet with records of the original settings, put in a bank cell in Switzerland. Now you are insured from failures, interference and curves hands. You can relax and start learning the instructions.
The main disadvantage of the FT-817 transceiver is the absence of a signal limiter in the transmitter. On VHF you can put up with it, but on HF. Low power + soft tone = poor audibility and low data. Attempts to make the SSB signal penetrative and dense, last for many years and began with the release of the device.
Western “boors” went the easiest, but not the most effective way. Made a separate design on the chip SSM2165 (SSM2166). On the Internet you can find such schemes. WiMo has launched the MH-31 microphone, with an integrated compressor card. The compression is about 8 dB. In general, the signal becomes denser and it gives a positive effect.
If you need a ‘hard’ penetration signal, I offer a simple, effective and cheap way with a domestic DEMSH-1A microphone. We connect it to the pins 4,5 on the RJ-45 connector. The signal is obtained as with a limiter and more penetrating than using a compressor on an SSM2165 microcircuit.
For DAMSH-1A, you need to adjust the timbre of your program, using points 56 and 57 in the advanced menu. It is important! The usual values of T LSB CAR are +150, and for T USB CAR -150. The gain in points 05 = 60, 29 = 50, the value 46, should be set to about 20 – 60 (I got 30). With a larger value, it is possible to transfer the signal. The microphone should be pressed to the edge of the mouth and speak clearly each letter.
Pay attention to the correct operation of the DEMSH-1A microphone. It is two-way, it is made specifically to suppress external noise. Therefore, it can not be shoved into the housing MH-31. DAMSH-1A should be open from two sides, look at this done on military headsets. The microphone is not afraid of strong moisture, resistant to frost and mechanical shock. In DEMSH-1A, the “correct” characteristic is that the best communication quality is ensured if at the transmitter side you increase the frequency response + 6 dB per octave, and at the receiver side fill it up with the same slope. DAMSH-1A in the transceiver YAESU FT-817, allows you to receive a signal that perfectly understands the noise. There are no complaints about the SSB / FM signals, but the AM modulation leaves much to be desired (with any microphone), in the old days, at 160 meters, such modulation would have been cheated in full, now it is no longer relevant, but for CB at 27 MHz and experiments – come down.
microphone MH-31 (native) Get a ‘sporty’, well-discerned signal with a native microphone will not succeed. You can slightly adjust the frequency response, using points 56, 57 in the menu. The signal will be ‘soft’ and pleasant for QSO neighbors when they hear you well. Gain in paragraph 46, set to 70-100. There is a weight in the microphone case, there is no need to carry extra weight with you in your backpack, it means you need to remove it. To do this, open the microphone housing, remove the board, with a screwdriver, carefully pick up the weight from the bottom and remove. If it does not give in, heat it with a soldering iron and remove.
Computer Headsets PC headsets can be used and very many of them have good signal quality. Buy only headsets with two phones and make a special adapter. When using a computer headset or microphone, note that the sensitivity of the condenser microphones is very high, so you need to work with them in a quiet room, otherwise extraneous sounds will be heard on the air. When working with a headset, it is necessary to decrease the gain in items 06, 29 and 46 of the menu 2–3 times. Computer headsets are not designed to work in the field, they are fragile, quickly break. The signal with them is saturated with a pleasant spectrum. In my opinion, they can be recommended when working in the premises (from the car in the parking lot), but not on the street. With pc headsets, the transceiver becomes prone to self-excitation. This is especially noticeable when connecting an external power amplifier and LW antennas.
Headsets from cell phones This type of headset can be used outside. Making a simple adapter for cell phone headsets may not work, because the button (which we can use as PTT) closes the microphone and needs to be re-soldered. Among the shortcomings, we can note the high sensitivity of the microphone (other sounds are audible), one phone (it is inconvenient to listen to HF in one ear), the need for soldering, the sound in the earphone is too high. Of the advantages: low weight, low cost and the fact that they do not attract attention in the city.
Let’s do the receiver. For comfortable work on the HF bands, it is necessary to select the RF-GAIN value in item 45 of the menu. On the air, on HF, without adjusting the gain on the inverter – you can not get a quality reception. With a constant maximum gain, the FT-817 will sizzle a lot and the reception quality will deteriorate. By adjusting the gain of the IF, it is easy to set the most favorable signal-to-noise ratio.
Pay attention to the points ATT (attenuator) and IPO (off. UHF). They should be turned off only on the HF bands. Of course, a lot here depends on the antenna, so experiment. Note that with any combination of these buttons, the dynamics of the receiving path increases.
Now let’s do the frequency response. The sound of the receiver, should be pleasant to the ear and without the ‘primusnogo’ hiss. There are several solutions. The easiest, go to point 54 of the menu and set the value to +200. In paragraph 55 set -200. What have we done? Slightly overwhelmed the receiver’s frequency response in the high-frequency region and got a more pleasant (for the ear) sound. The above values are approximate, guided by your hearing. The receiver should not hiss! This is the easiest and most inefficient way.
The best option, recommended for professional communications, is a roll-off frequency response of -6 dB per octave in the high-frequency region. It can be achieved only by soldering parallel to the capacitor C1337 (on the MAIN-Unit board), an additional, approximately 1500 pf. You can make an alternative, it is easier because you do not need to get the fee MAIN-Unit from the case. We take a capacitor with a capacity of 22000 pf (we select from 10n to 22n) and solder in the place indicated in the picture, parallel to the resistor R1315. The effect is about the same. After that, we again adjust the values of R USB CAR and R LSB CAR and enjoy the new sound of the receiver. Disappears ‘primusny hissing’ characteristic of all low-frequency paths with a wide bandwidth. What I got (you see in the picture above) with a value of 0 in paragraph 55. Your ears will thank you!
The next method, the most expensive, but it does not exclude the previous ones, but rather harmoniously complements them. This is the replacement of the standard simple filter with an optional YF-122S for SSB or YF-122C, if you prefer Morse code. Optional filters increase the selectivity and uniformity of the frequency response. For the analysis of pass-through frequency response of the receiver, the Spectrogram program was used.
The FT-817 also has other means to deal with interference on the air. First of all, it is the IF shift, which allows you to separate from the powerful signal of the neighboring radio station, from the carrier and reduce clogging. To turn it on, press and hold the CLAR button for 3 seconds and then turn the SEL knob. Also, at our disposal there is a noise suppressor NB. In some cases, it is quite effective and finally the last bastion of high-quality reception, this is AGC in the AGC menu. For a comfortable reception of SSB, we use a slow AGC (AGC slow). When a weak radio station is blocked, with a strong signal, we change the mode to AGC off.
about headphones and speakers A person evaluates what he hears (first of all) according to the characteristic of the sound itself and only then begins to comprehend the information that this sound carries. Therefore, it is very important (except for the frequency response of the receiving path) that the speaker or the phones to which you are listening to the signals have the ‘right sound’. only in this case you will not have a feeling of discomfort. By ‘correct sound’ is meant the phone (speaker) characteristic in which from about 200 Hz a smooth rise begins, reaching its peak in the region of 500 – 1500 Hz and further up to 6000 Hz there is a smooth decline with a slope of -6 dB (-10 dB) per octave. That’s why HEIL headphones and headsets are highly appreciated by hams! They have the ‘right characteristic’, even noisy signals read well in them and their hearing is not overstrained. And in computer (and other) headphones, the frequency range is made as wide as 20 to 20000 Hz. and they are not suitable for radio amateurs. However, there is a way out, using ordinary computer headphones (or speakers), but incorporating a low-pass correction filter in them to get the ‘correct’ frequency response.
To increase the battery life of the FT-817, you should know that in SSB mode, turning on ATT reduces power consumption by 10mA. Turning off the display illumination reduces the current consumption by 30mA, and switching ANTENNA (in the menu), another 30mA. Total, we already save 70mA, simple manipulations!
Connecting headphones, instead of the speaker, saves energy only at high volume levels. Thus, the minimum current consumption of the receiver on the HF is approximately 270 mA (at a voltage of 12V) and 250 mA of the VHF range, if you turn on the backlight and switch the antenna to the rear connector, the current will increase to 330 mA.
When the transceiver is connected to an external battery and power supply, through the plug on the back side, even when turned off, it consumes
The efficiency of the transmitter can be improved only by lowering the power. Although, the current consumption of about 2A at 5W in the antenna, can be considered a good result. At 10W, the current consumption increases to
By purchasing this transceiver, the radio amateur probably assumed its use in the field, because there are other models for stationary (automotive) work. In the simplest case, you can just take the FT-817 with you and go somewhere, but an advanced amateur radio traveler will definitely prepare himself and his friend (in the sense of a transceiver) in advance. Look at the photo of one of the variants of the ‘combat kit tourist’.
The FT817 is not designed to work in adverse weather conditions. The first enemy is moisture, so buy or make a case. It is very good, if in a cover bag there are additional pockets for a notebook, a pen, a pencil, a sharpener, erasers, amateur permission and so on.
The transceiver is afraid of moisture, so when carrying it in a backpack, wrap the 817 in a plastic bag. Working on the transceiver in the rain is absolutely not recommended. Keep the transceiver away from condensation. To minimize the ingress of moisture and dust, close all unused plugs with plugs, and inside the case, put the bag in a moisture-absorbing composition.
If the transceiver gets wet in the rain, dry it as soon as possible. During the multi-day trips, I repeatedly did this, removed the covers and dried the transceiver on the stones. After that, it works great again. Be sure to take a cross-shaped screwdriver with you on your trip. Here is a photo of where I land a transceiver and other things, after the rain, in the mountains, at an altitude of 2600m.
Sometimes, dragging a heavy CW key does not make sense. But in order not to put an end to this type of connection, put a subminiature CW-key in your pocket. That and without telegraph you will not leave and the antenna will help to quickly coordinate. Despite the non-standard design, a QSO can be made on such a CW key and used to tune the antenna with a tuner.
Microphone MH-31 is not designed for operation in difficult weather conditions. In the cold, the membrane is quickly covered with ice from your breath. The wind will blow strongly into the microphone and it will not be possible to disassemble your voice, and if the humidity is also high, you can wind up and go home. To protect from the wind, wrap the microphone with a regular handkerchief or use DEM-1A.
When operating the device on the street, it is recommended to buy and install an additional block for stabilizing the frequency of the reference TCXO-9 generator (it is already installed in the FT-817ND), frequency stability depends on it, especially with sudden temperature changes.
To quickly find the desired function in the menu and quickly control the transceiver, print this table. In which are listed all the possible combinations of multifunction buttons A B C. So you can not waste time finding the right button.
memory organization It is useful to ‘hammer’ some frequencies in the transceiver in advance. For example, common QRP frequencies for SSB:
Pay attention to the HOME button. Often, it is more convenient and quick to use than memory. However, this button can program one frequency for HF, and one frequency for VHF bands 145 and 438 MHz. I offer these options: 28600, 145500, 438500kHz. These are our local frequencies on CMS, for operative communication, they may be different for you. For many other regions, in HOME for HF, it is better to record the duty of the CB-27 MHz frequency.
Extreme Operation Using the FT-817 on hikes, I managed to ‘grope’ for critical modes. For example, if the transceiver cools down to -10 ° C, it will not work properly. In my specimen, cooling is indicated by low return to the antenna and the constant flashing of the HSWR inscription, although the antenna is known to be working properly. You may have other signs (for example, reception is deteriorating), as they say: “where it is thin, it breaks there”. After heating the case, normal operation is restored.
You can supply voltage to the transceiver in two ways, through an external plug or through the internal battery compartment. Here is a table with voltage drop measurements, depending on the type of power supply:
It follows from it that it does not make sense to power the transceiver from the FBA-28 unit and, accordingly, from AA batteries, due to a large voltage drop. The voltage drop occurs because there are microresistances between the contacts in the FBA-28 unit and each of the eight batteries experiences different loads and gives a different current! Still in the transceiver itself “disappears” approximately
ATTENTION! Negative wire from an external power supply to which the FT-817 is connected must not be connected to the housing directly! Grounding is not a minus wire, and the body!
What happens if you apply voltage to the transceiver simultaneously from two different sources (from the internal battery and from an external power supply)? Nothing wrong! For automation, power from an external source has priority, so the transceiver will work as it does when powered from an external source. But, as can be seen from the diagram, both the connected power sources will release the current. Note that the transceiver is not afraid of reversal. In the picture you can see a simplified voltage supply for the FT-817. Diodes protect both inputs from incorrectly turned on voltage.
Voltage drop on
powered by AA elements The transceiver has a FBA-28 compartment for 8 AA batteries (voltage 12V). Food from these elements does not cause trouble. Inserted and use, discharged – pulled out and thrown out. The instructions say that you need to put AA batteries into the compartment. A set of good batteries last for 30 minutes of active work on the HF. Why so little? The point is microresistances arising between the batteries. Batteries can also be inserted into the battery compartment. The most common batteries (with us) are GP 2700m / h, but the operating time does not increase.
Batteries inserted into the FBA-28 compartment can be charged using the built-in charger (the charging current is 178mA and the time is adjustable). To do this, you must first tear off the green wire in FBA-28, otherwise there will be no charge.
Powerful batteries (2700m / hour) may not have time to charge for 10 hours. The fact is that GP needs more current and needs to be charged separately, this is important. In the form of a battery, they will not be able to gain full capacity, because parasitic resistances arise between the contacts, they are very small, but this is quite enough for the battery so composed to fail to gain capacity due to the spread of internal resistances. Therefore, to charge the batteries, we buy separately two chargers (4 GP each).
The charger must be of high quality, because only in expensive chargers, each battery is charged and controlled by a separate circuit. This is very important for quality charging! Well, if the memory will provide a forced discharge mode. Batteries of 8-charged GP 2300, just enough for a few tens of minutes of active work on the HF. To increase the time of work, you need to solder them together to eliminate transient resistances and uneven discharge. In this case, you are guaranteed 1 hour of work on the air.
about microresistances With a large number of batteries connected in series (from 4 or more), parasitic microresistances appear between them. In our case (when using the FBA-28 compartment), they do not allow the current to be given to eight batteries evenly. Moreover, in the reception mode, it is noticeably less pronounced than during transmission. So it should be, with an increase in current, parasitic resistance manifest themselves stronger. This explains the short work of the transceiver with the FBA-28 unit. Some batteries in the unit are discharged more strongly and the voltage is already falling on them, while the others remain practically uncharged. Note that from a separate battery of the same capacity (for example, from backup power supply units for a PC) the transceiver has been confidently operating for 2–3 hours.
ATTENTION! It does not make sense to power the transceiver from the batteries or batteries placed in the FBA-28 compartment. It is much more efficient to use a FNB-85 battery or an external battery with a larger capacity.
2300mAh / h battery Based on the above, it is clear that it does not make sense to use standard 1000mA / h and 1400mA / h batteries, they do not work for a long time. Let’s make the battery yourself! We buy eight GP batteries at 2700mA / hour and solder them sequentially. Be sure to short (10mm) and thick wires. Then we wrap with tape, for the fortress. Such a battery fits in the compartment and allows the transceiver to operate longer than that of the FNB-85.
We connect the new battery pack to the transceiver, take it from the old battery or the FBA-28 compartment, there’s no point in it. Green wires are cut off, otherwise your battery pack will not be able to charge.
We increase the charge current. Now we need to resolve the issue with the charger. You can use external memory with a current of 300 – 500mA or built-in transceiver. There are no differences from charging a standard battery in this case. Charging time is always set at 10 hours, because the charge current in the transceiver is only 178mA, which is not enough even for the FNB-85, not to mention the larger capacity battery. To increase the charge current, parallel to the resistor R1426 we put another one, with a nominal value of 510 ohms, so we increase the charge current to 310 mA and in 10 hours our battery pack has time to charge normally. In order for the battery pack from GP to give up its full capacity and work for a long time, the following conditions must be met:
- You can start discharging only when the battery pack is completely discharged.
- GP battery charge can not be interrupted, even for a few seconds! If this happens, you need to discharge the battery and start charging again.
- You can not recharge the battery pack is not fully discharged!
- You cannot use the battery pack on GP cells as a buffer when powered by a solar battery, for example!
use the battery compartment for purposes not intended. If you use an external battery, the space under the compartment remains free and can be adapted for other purposes. For example, put there the necessary supplies in the campaign. The compartment has dimensions 110x61x16mm and is covered with a lid. You can easily put headphones, a sharpener, a pencil, a small notebook, a screwdriver, a PL-CP adapter (for a front panel connector) and so on. So, we have at hand everything you need to work on the air and write QSO.
We cut the ‘wings’. In the back of the FT-817, two ‘wings’ protrude on the sides, they are a continuation of the hull. What function do they perform? Based on them, the transceiver can be placed vertically. Everything! No more. Then why are they needed? Cutting them off you will not lose anything, but the transceiver becomes much smaller, it is easy to shove it into a small bag and backpack. True, it’s not possible to put the transceiver vertically, but whether it is necessary — usually not. The material from which the ‘wings’ are made is very soft and you can easily cut or shorten them with a regular hacksaw. After that, take the file and grind the remaining parts so that there are no burrs. If you think that the ‘wings’ perform the function of a heat sink to remove heat, then you are mistaken. In practice, it is verified that field-effect transistors (in the output stage) “fly out” from their own overheating faster than the “wings” have time to heat up.
solar battery In multi-day radio expeditions, it is not possible to take large capacity batteries with you. Only one way out – solar battery + backup battery from backup power sources with a capacity of 4-7A / H. The main advantage of such a battery is that it can be charged and stop charging at any time, there is no memory effect.
I usually use the battery SEALED LEAD-ACID BATTERY
To work in the field with FT-817, it is recommended to study the experience of using professional low-power HF equipment, which was actively used in the national economy of the USSR. First of all, these are the radio stations KARAT-M, NIVA-M, GROZA-2, DIAMOND-M with the power
Work on the HF. Summarizing the experience of the national economy of the USSR, geological exploration and the military, it can be said that the main antennas for HF communications over distances up to 40 km are strongly shortened pins. Usually their length
The main leitmotif (which you must comply with) for successful operation at low-power HF is: ‘The lower the power, the larger the antenna’. Saving on the weight of the transceiver, you do not have to save on the weight and size of the antenna. Therefore, I don’t even suggest you carry short pins without counterweights.
As emergency operational antennas, we can consider designs that are produced specifically for wearable HF transceivers, these are ATAS-25, ATX-1080, AT-10 (15,20,40), Buddipole, Buddistick, XR-100, HFV-5, MP-1, RHM-5, AH-703. Since they are all very shortened, the one that has a great length will work most effectively. Radio amateurs estimate ATAS-25 and Buddipole. On the other hand, they will always lose to full-sized structures of the type:
about matching devices Additional matching between the antenna and the transceiver, with a power of 5W, greatly reduces the already small power of the transmitter. The efficiency of a well-made matching device with a small transformation ratio is 50 – 70% (1: 2 – 1: 3), and with an increase in the transformation ratio, it drops to 20 – 30% (1:10). Remember this! It’s easier to make an antenna with a resistance of 50 ohm, at the desired frequencies. There we will get the maximum efficiency of the system ‘transmitter + antenna’.
On the other hand, when using antennas ½λ and longer, the losses in the matching device are compensated by the gain that has appeared in the antenna itself. But on expeditions, such long antennas are used only from 14 MHz. and higher. In this regard, I recall Igor Grigorov’s camping antenna, which works well in field conditions. In difficult weather conditions (in winter, at night, at a height), simple and reliable antennas, such as the ¼λ pin and a half-wave symmetrical vibrator without additional tuning elements, have proven themselves well.
Work with MFJ-902 For travel lovers, MFJ produces a small and lightweight MFJ-902 antenna tuner. Since the SWR meter is already in the transceiver, the setup of any piece of wire is done by pressing the CW key, at its smallest power. During setup, the MTRswr item in the menu should be enabled. If you do not take a telegraph key on a trip, you can make a special button that is inserted into the KEY jack. We look at the photo: photo1, photo2, photo3, photo4.
near VHF communication For carrying out VHF QSO on the go and for communication up to 5km, you can use a regular ‘elastic band’ or a quarter-wave pin. A longer antenna is better.
Compatibility with LPD / PMR / CB radio stations The FT-817 transceiver (after opening) can provide two-way communication in FM mode, with unlicensed LPD / PMR radio stations that anyone can use. LPD is 69 channels in increments of 25 kHz and deviation to 5 kHz. PMR466 range has 8 channels in increments
In the range of 27 MHz (CB), you can use not only FM, but also SSB, AM modulation. Sometimes there is a lot of interference from distant radio stations and industrial interference, but outside the city, switching to the CB can be justified. To work on the go, you can use the eraser from any portable CB radio station. The communication range between CB stations is 1–15 km, depending on conditions and antennas. Most CB radio stations do not show the frequency, but the channel number, so it is useful to have a table of channels and frequencies. The frequency range of CB lies in the limits
About the possibility of increasing the power of the transmitter FT-817, a lot has been said. So is it worth increasing power? Everyone decides for himself. On the one hand, 10W. in the antenna will not interfere, but at the same time reliability is lost and you need to carefully monitor the thermal regime
Newer FT-817s usually have power.
It is recommended that the maximum power not make more than 7-12W. At the same time, there is still sufficient reliability of the transmitter, protection works. Does such a small increase affect the quality of communication? From a theoretical point of view, this is not essential, but the practice suggests that sometimes (not always) increasing the power from 5W to 8W allows you to more confidently conduct a QSO, especially when you work with reflection from the ionosphere. It is possible to raise the power through the engineering menu, very carefully, constantly monitoring the instrument parameters. If you have clocked up the power, it is better not to power the radio station with a voltage of more than 12V. UA0LLM, has a positive operating experience of the transceiver at 10 – 15W, in campaigns.
Some versions of the FT-817 do not allow an increase in power of more than 8W. It manifests itself in such a way that when you increase the power in the engineering menu. It gradually grows, up to a certain level, and then does not increase. It is necessary to ‘catch’ the moment when the power stops increasing, then reduce the level by another 2 – 3 steps and leave it like that. This will be the highest possible transmitter level.
work with an external power amplifier If you can power the transceiver from a powerful battery or network unit, then you should use an additional power amplifier. I tested the FT-817 with a KL-500 amplifier. The results are positive! The signal quality does not deteriorate, and the real power in the antenna is approximately 170-240W. on the HF bands. It depends on the KL-500 amplifier and on the power output of the FT-817 itself. My power output to the antenna is 7W, and after the amplifier about 200W is obtained. (pressing in CW), current consumption 23A. Peak values of power reach 260W and current up to 28A. With the KL-500 is convenient to work at home or out of the car. Here are the photos: photo1, photo2. A wire length of 7 meters was used as the antenna. No interference, spurious emissions and distortions were noticed. Average reports from correspondents at 14 MHz are: FT-817 + KL-500 = 59 + 5 dB / FT-817 (5W.) = 54
The KL-500 needs to be turned on only for a well-matched load, therefore, between the amplifier and the antenna, we must turn on the antenna tuner designed for a power of at least 300W. All antenna matching, we carry out with the KL-500 turned off! You can recommend the MFJ-969 (MFJ-962D) tuners for matching with pieces of wire, beams, pins, unbalanced cables (50, 75, 100) and MFJ-974HB for balanced antennas powered by an open line.
It is not recommended to use this transceiver for digimode operation, since it overheats after 2 minutes of continuous transmission, at full power (5W). Rather, the 817 is suitable for individual power experiments.
Given the possibility of overheating and low power, the question arises: Which digital communication types are best suited for the FT-817? From the point of view of the minimum load on the transmitter power amplifier, Hellschreiber mode (FELD HELL) is preferred, and the maximum range, with
ATTENTION! Sound level settings from the sound card to the transmitting path, make only at reduced power (
It is not recommended to work in SSTV, FAX, WINDRM and DIGTRX modes on FT-817. Batch mode (PACKET RADIO) allows you to connect to amateur networks on the HF-VHF and get access to DX-clusters, mail systems, forums, file servers, APRS, and so on. In a ‘package’ at speeds of 300 and 1200 baud, the FT-817 works very well. I did not check the 9600 baud rate.
In this section, I summarized my and others experience of operating the YAESU FT-817 transceiver so that you pay attention to these factors in the first place and always remember them. So the most unfavorable effect on this transceiver:
- The supply voltage is higher than 14V (many recommend limiting the voltage to 10 – 12V.)
- Overheating of the output stage (usually in digimodes and FM), turn on 1min. in paragraph 49
- Increased humidity (rain, snow)
- Excessive increase in transmitter power in the engineering menu
- Low temperature, from -5 ° С
- Curved hands (or hands growing not from there)
- Bad head
The list does not indicate a high CWS, because of this the transceiver has protection, and when the CWS rises, it reduces power. But thermal protection is not, therefore, control over overheating is extremely important and you should follow this yourself. The transceiver is not afraid of reversal, you can not worry about this.
I express my gratitude to rv3dpm for providing the transceiver and the guys from the Elbrus mountain rescue service, for help in writing the article.
written in June 2006 (updated October 2013) North CaucasusUA6HJQ