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write your own review of the Yaesu FT-902DM.
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K5KEN
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Rating: 5/5
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Mar 8, 2010 05:11
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What can I say....!
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Time owned: 3 to 6 months
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We'll for my first review on my first HF radio all I can say is wow! My 902DM is in near perfect condition for being built in 1981. The gentlemen I bought off was the first owner and for the past 15 years has only used it on AM.
I have no drift on either the main VFO or the FV-101Z VFO. I also got the SP-901P with my deal. I had to replace the 30 y/o speaker which had dried out, which was no big deal to do.
I did have the the 3 final tubes replaced which where the original one and my tech did a quick alignment which to my surprise was still set to factory spec's and still pretty close!
As my first HF rig I am very happy with it.
I really enjoy the 902DM and for the price it was a great deal.
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N8YX
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Rating: 5/5
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Sep 23, 2009 17:57
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A solid performer - IF...
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Time owned: more than 12 months
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Anyone reading this might first want to check out the FT-901DM review section, particularly where the comments relating to frequency stability are concerned.
I recently got hold of a "drifty" '902. It is the second of these radios I've owned; performance of the first rig mirrored other reviewers' experiences.
This one, however, would drift a total of 5 KILOhertz in 24H from a cold start!
A search around the 'Net directed me to a site which detailed another amateur's VFO repair tale. In his case, bad N750 temp-compensating caps in the '902's internal VFO led to a severe drift condition. My rig suffered from exactly the opposite problem: Some of the NP0 caps were way off spec. In addition, a bad 20pF NP0 in parallel with the reference oscillator crystal's trimmer cap on the digital readout board made netting the display to WWV impossible. Replacing the part fixed the problem, but a sporadic drift problem was still observed. This was ultimately isolated to the ATT/RIT/XIT switches...dirty contacts...and floating voltage reference levels. A shot of Faderlube F5 and a drop of DeOxIt in each switch fixed the problem.
Drift is now ~400hz in 3 hours (from a cold start) and ~40hz per hour thereafter...which is well within Yaesu's specs. (The author of the repair article got his rig's total drift to within 300hz, so better VFO performance is possible!)
If the lack of computer control, general-coverage receiver and the presence of a tube PA doesn't bother you, these rigs will do anything "on the air" that you wish.
If you get a problematic example, they're not that difficult to fix. Aside from the digital display IC, the various capacitors used in these rigs quite possibly are the only components which will give an owner any sort of grief...and they can be replaced if necessary. Clean those switches and potentiometers as well.
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AC5XP
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Rating: 5/5
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May 26, 2008 11:48
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Yaesu's number-one classic!
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Time owned: more than 12 months
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The FT-902DM radio I think is Yaesu's #1 classic. It basically is the last of a family of radios that started with the FT-101 and went on in evolution through the FT-101ZD and the FT-901. As such, it is the last and best of its class. It actually is much better than the FT-One which came out later after the FT-902DM.
The 902 looks like the 901, but it differs from that radio in major aspects. The most important improvement that the 902 offers over the 901 I believe to be the improved receiver front-end, which was already pretty good in the 901, that one being the first to use a double-balanced mixer. (The 101 series only used single-ended mixers in the receiver front-end, using a dual-gate MOSFET).
Everything on the 902DM radio works very well and as such it is a pleasure to operate. Also from an ergonomic standpoint Yaesu did a good job here. Large knobs well laid out on an aluminum diecast front panel complete the impression of ruggedness.
The digital readout will require calibration when you buy this radio used, but once you have done so it stays very constant. Which is actually strange because the radio uses the same frequency counter board as the FT-107M and the FT-707 but for the latter radios the counter drifts about 200 Hz from warmup. On the 902 I have not noticed this, maybe a better quality of crystal was used for the counter board.
Just to make sure, I’m talking about the frequency counter accuracy, NOT the VFO stability because the latter drifts much more from warmup, about 400 Hz. But that is easily compensated for by adjusting the radio dial back to the correct readout. When the counter drifts however, this error cannot be compensated for, so that is why it is so important that the counter time-base is drift-free.
All boards in this radio are of the plug-in type. Nice to quickly replace a board but not so nice if you need to work on them because you will need extender cards which are not easy to get.
What is really neat on the 902 is the memory feature. Nowadays memory features and second-VFO capabilities are easer than 1-2-3, one just stores the frequency code for the digital synthesizer in as many memory registers as one wants. But in the days of the free running VFO’s (as the 902 has), this was much more difficult to accomplish. Yaesu basically solved the challenge by measuring the 5 MHz VFO frequency in a counter, and using the counter result as the frequency code for a second VFO based on a digital synthesizer that spans the same range as the main VFO (5.0 MHz to 5.5 MHz) In this way, a particular set VFO frequency can be memorized and reproduced by the synthesizer. Now you also will understand why this only works within a set band; because the master VFO is re-used for each band. As an example; suppose you memorize 3.800 MHz; then on 40 meter the memory channel results in 7.300 MHz, on 20 it would be 14.300 MHz and so on. That is also the reason why cross-band splits are not possible in this concept. But within the same band it works well.
For the 902, the synthesized memory VFO uses a very low step-size (100 Hz resolution) which results in a very slow settling time (several seconds) because of the low cutoff frequency for the loop filter (probably less than 10 Hz) combined with the fact that this is only a single-loop synthesizer. But it works well, albeit without the possibility of a memory RIT function; what you store is what you get, rock-solid but nothing more.
The same memory concept is used for the FT-107M and the FT-707 external VFO. But for the FT-107, it was implemented slightly different; there the resolution is 1 KHz where the 100 Hz steps are made outside the PLL (by pulling the reference crystal). As a result, RIT is possible but synthesizer over-all stability is heavily compromised. I therefore prefer the method used for the 902.
The FT-707 digital VFO has this implemented the best though; it uses a two-loop PLL capable of making 10 Hz steps without the need for shifting crystals. As a result, this synthesizer is fast with a high resolution while maintaining stability. But at the cost of added complexity.
Back to the 902. I really have nothing bad to say about this radio because everything works well. The receiver uses a manually tuned front-end which, in combination with the double-balanced mixer yields an excellent near-frequency rejection of unwanted signals.
And because it is a single-conversion receiver, the IF crystal filters ARE the "roofing filters", the latter concept a popular advertisement slogan for today's radios. Let's not forget that "roofing filters" became a necessity because of the general-coverage up-converting receiver concepts that became so popular soon after the 902 saw the light of day.
Another nice touch on the 902 is the variable IF filter concept which works very well. One really would not need the optional 500Hz filter because of this. Just to be clear; this is NOT a simple IF shift. It is a true variable IF setting which is done by letting two sharp-edged crystal filters "run into each other" (an old Collins patent who used the concept extensively in its high-end receivers)
By the way, the same concept is used for the FT-107M and the FT-707, as the latter radios share a lot of DNA with the 902 and are clearly designed by the same Yaesu engineers who did the 901/902.
Another great feat is the tube PA, with 6146 tubes, thus abandoning the sweep tubes as used for the FT-101 series. Sweep tubes seemed like a good idea at the time due to their abundant availability for the TV market, but when the 901/902 were released that was not the case so much any more. We have to thank Yaesu for that decision because the 6146 is still easy to obtain in today’s markets, where this is much harder for the sweep tubes.
What else can I mention? The excellent speech processor; the very well performing AM and FM modes; the high quality of build; just to name a few.
And last but not least, this radio really LOOKS and FEELS like a HF transceiver. This in contrast to today, where radios apparently all need to look like something that walked out of Darth Vader’s living room, in an attempt to appeal to the X-Box generation…
73s, Loek "Luke" d'Hont, AC5XP
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M0RTS
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Rating: 5/5
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Jul 25, 2007 06:39
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Great Example of its time
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Time owned: more than 12 months
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I have owned one of these gems for 8 years now since i have been licenced.
Transmit reports have always been cracking with excellent audio,have heard this radio on the air when it was on loan to another ham and could not believe what i was hearing. The reciever is sensitive and pulls in the weakest of signals.My friend who borrowed this beast went out and purchased one himself.
I run mine with the matching accessories i.e External VFO,ATU,2m/6m/70cm transverter and monitor scope. All works well especially transverter 10watts output on 6 metres is great as is 2m and 70cm for local ragchews.
Very reliable and built like a tank, cannot justify buying new radio with bells and whistles when this one is more than adequate.
Only snag is that the line up is very bulky equipment but we can make an accept this as these radios were not built in recent years. If anyone needs a radio to get on to HF i would suggest this one anyday of the week. If you have no experience of plate and load this may be slightly different at first but performs just as well as any modern rig.
73
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GM0ELP
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Rating: 5/5
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Dec 30, 2006 03:32
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Good, reliable fun
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Time owned: 3 to 6 months
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Having read all the reviews, I just had to have one ;-). I was now looking for a miracle in terms of performance and definitely didn't get that in comparison with modern day radios such as FT1000MP MkV (no big surprise). However, it has a very sensitive receiver and comes with some nice extras which seperate it from similar older radios.
The APF feature is a joy for CW ops and just seems to 'pop' the wanted signal out whilst rolling off all the background hiss.
The width control allows interference handling cabability for SSB and CW contacts, although even a small change in this control will result in noticeable attenuation to the wanted signal.
The on-board keyer is great although I found I couldn't send a 'C' without waggling the paddles instead of just squeezing (I'm used to Iambic B).
The single memory allows QSX and quick QSY without the use of XIT/RIT which is handy for working the occassional DX.
RX audio is very rounded making large signals sound great, but I found it difficult when working weak stations and found myself swapping to the MkV or the IC751a.
This must have been a radio to be reckoned with in it's day and still holds it's own today as a useful, fun, reliable hybrid for those of us who like rigs that glow in the dark.
It's very easy to tune and has a nice feature that releases the PTT after a predetermined period to prevent damage. This probably explains why these radios are so reliable.
I've given this radio a 5 not for out and out performance but for it's reliabilty and extra features which make it a useful radio even by todays standards.
If you must have a valve radio then give this one serious consideration.
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KB0HAE
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Rating: 5/5
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Dec 12, 2006 01:22
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The BEST Yaesu radio ever!
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Time owned: 3 to 6 months
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I owned one of these great radios for about 4 months. It is the BEST radio Yaesu ever made! Very well built radio, very sensitive and selective receiver, and sounded almost as good as the Kenwood Hybrids. I always got great RX audio reports with just the Yaesu hand mic. I liked the 100Hz audio filter for PSK. The VFO was very stable, and I never had the slighest bit of trouble with the radio. Much better performance than any of the newer Yaesu radios. If you find one of these at a good price, buy it!
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MW0HRD
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Rating: 5/5
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Jan 5, 2005 18:45
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good solid radio
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Time owned: more than 12 months
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I have now owned my FT902DM for about 16 months and for its age had only the usual problems when i first got the radio relays switches etc nothing much. I have worked the world on it and would not part with it never had a bad report the audio is superb. with 100w out I paid £150 you cannot go wrong. I would recomend this radio to anyone. but do not get one if you dont like to plate & load
73 to you all Chris S-Wales
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PY3KT
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Rating: 5/5
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Dec 20, 2004 08:44
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Great radio
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Time owned: more than 12 months
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I appreciate so much this type of equipment, therefore as a friend said: "tube radios have soul". Excellent receiver and trustworthy transmitter, with good quality of audio. It is between my preferring, because remembers my old Yaesu FT101-ZD and it adds quality in all the directions.
73 and greetings from Brazil
PY3KT - Joel Costa
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VE8NSD
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Rating: 5/5
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Oct 15, 2004 11:27
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I like mine, but...
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Time owned: more than 12 months
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I got mine as part of a package deal with the phone patch, ant tuner, VFO, and 'scope.
The Astatic D104 really makes the audio sound good. I received a lot of unsolicited compliments on my TX audio.
I saw an Inrad SSB filter on eBay, bought it, and love it. The transformation is literally like having a different (better) receiver. Really incredible. BUT the drawback is that the receive audio now is "communications" quality instead of "high fidelity".
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G1EUZ
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Rating: 5/5
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Aug 12, 2004 12:08
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Keeper
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Time owned: more than 12 months
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I have 2 Radios, the ICOM 718 and the FT-902DM.
It took me 12 Months to refurbish the 902DM fully, I bought it with several parts missing, and managed to track them down via the web. Now I cannot leave it alone.
A useful link for the counter board replacement chip is here:
http://homepage3.nifty.com/RadioGaGa/COUNTER_e/
also check out the 901/902dm group on yahoo:
http://groups.yahoo.com/group/FT-901/
The modern Icom rig is great for fast fun, but for that lamplight and heater glow, I keep returning to the 902DM. Alignment can be tricky, but when you get it right - it's great.
Mick
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