Icom 751a: opinions wanted
Peter A. Klein
ICOM radios and/or the TS-850?
Background: I've decided to replace my aging Icom 745. Reasons: it
won't do AMTOR, has problems with overload, spurs and distortion under
crowded conditions, and tend to heat up and drift when transmitting. If I
buy new, I'll probably go for a Kenwood TS-850SAT. It appears to be a
better radio than the similarly-priced Icom 738.
But I'm also interested in a quality used radio which would be a truly
*significant* improvement over the IC-745, but cost less than the TS-850.
Also, I have an Icom desk microphone, power supply, FL-44 deluxe SSB
filter and 500 Hz CW filter that could be transferred to a newer Icom
radio. Icom's service center is right here in the Seattle area. So I
have some reasons for staying with Icom.
Based on the above, I've thought about getting a used Icom 751a. However,
after reading the ARRL Radio Buyer's Sourcebook (reprinted QST reviews)
and talking to a few people (including ICOM service), I'm confused. I've
been told that "the 751a was the best radio Icom ever made." I've also
been told that the just-discontinued IC-735 receiver will outperform the
751a, that the 751a runs hot, and that the 751a has a similar front end to
the 745 and may have similar overload problems.
The QST reviews are not much help, as their review is of a 751, not a
751a. Also, I'm not sure how much I trust them. QST's 3rd order IMD
figures for the 745 on 20m are better than either the 751 or the 735(!)
For reference, I'm not a competitive DXer or contester. I do like to DX
(mostly on CW), but not obsessively. To me contests are just a convenient
way to work a new country or two. I like to ragchew on both SSB and
digital modes (mostly Pactor these days, and want a radio that will do
Amtor). So I don't really need "instant QSY" memories and contest-winning
features, though the ability to work "split" is important.
OTOH, I like having good, steep-skirted filtering and variable bandwidth,
aka "passband tuning" in both CW and SSB. And the ability of the receiver
to resist overload is important--I live in a city with a lot of big guns.
Adjustable CW sidetone pitch that tracks with transmitted signal would be
nice, though I've lived without it until now.
Does the 751A have the software in battery-backed RAM like the 745,
or in ROM like the later models?
All advice, anecdotes, passionate opinions and wild rumors welcome :-)
73 - Peter, KD7MW
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Joseph Martin Fitter BV/N0IAT
comparison (field day / cw dx contests), I opted for the 751A over the
735. While the 735 is a good solid rig, I found the following to be
better on the 751A:
Filters: the 751A has filter cascading and uses dual-if filters.
Power: the 751A loafed along driving the L4B amp with no heating prob.
Meter: the 751A had a bigger front-panel meter
Rcvr: I've found my 751A to be nearly bullet-proof in high RF
environs. Also, the passband tuning is circa Collins era and
is excellent. In fact, ICOM got into trouble and hence had to
modify the circuit in the 735 and 761 to avoid a patent
lawsuit. (so I'm told)
I DO have a couple complaints though as follow:
1. Memory and CPU data is stored by lithium battery (not newer eprom
technology). Hence, when the battery dies, so does the rig. It requires
a trip to the repair shop to replace the battery and reprogram the
volatile RAM. Thankfully, mine has yet to die! I'm living overseas, so
repair wont be easy if it does go south. I am now investigating the
"aftermarket" eprom boards that install inside the rig...the data is
burned in the eprom so once you replace the board you never worry again,
and at about 100 bucks its cheaper than a trip to the factory!
2. After 1 month, mine developed a quirk. Sometimes, when mode-changing
from SSB to CW, the VFO would not lock. A trip to ICOM Service quickly
fixed the problem in warranty at no charge...it was a bad crystal that
controlled the CW lock. Icom service was so good, in fact, that I had
the rig back before I got the little "your rig was received by the repair
center" card! Amazing.
3. QSK on the 751A is not "superb". It is good, but the VFO CPU does
not lock fast enough to do a lot of split-band / split mode high-speed
QSK. This only effects me if working split on 40 meters above about 40
wpm. At that speed, the CPU wont lock fast enough and the first dit of
the characters becomes very short. On same-band split (when working most
DX) the rig performs very well.
All in all, I'd buy one again. I also use a Yaesu FT-890, Alinco DX70,
and have had an FT-1000 and a TS-440. Still like the Icom best.
73 Joe
BV2/N0IAT in Taipei, TAIWAN R.O.C.
Ex 7J1AOF Ex KA0ZDH Ex. YU3/N0IAT
Licensed Radio Amateur since 1986
Pasi Tuomi
>All in all, I'd buy one again. I also use a Yaesu FT-890, Alinco DX70,
>and have had an FT-1000 and a TS-440. Still like the Icom best.
>73 Joe
Yes. IC751A is vy good rig. I agree with Joe.
There has been some tests abt the rig and the results have been
suberb. We are also tested 765 and 751A and we didnt find any
big differences, both are very good.
We have to remember that model 751 is not same as 751A which has
better rx (same as in IC-R71 ?)
Pasi, OH3NPS, OH5NPS
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Steven Gray
: Based on the above, I've thought about getting a used Icom 751a. However,
: after reading the ARRL Radio Buyer's Sourcebook (reprinted QST reviews)
: and talking to a few people (including ICOM service), I'm confused. I've
: been told that "the 751a was the best radio Icom ever made." I've also
: been told that the just-discontinued IC-735 receiver will outperform the
: 751a, that the 751a runs hot, and that the 751a has a similar front end to
: the 745 and may have similar overload problems.
Peter -
I can only coment on one aspect of your posting. I owned a 735 for a couple
of years, and have had the opportunity to operate a friend's recently
purchased 751a. There is simply *no way* that the 735's receiver is as
good as, or better than, the 751a's receiver.
When using the 735, I always thought it was a mediocre, noisy receiver -
I never missed the rig after I sold it. The 751a always seemed more
sensitive and less noisy; personally I'd buy one in a second *if* I could
afford it.
Good luck!
---Steve Gray
nr3b
Fraser Robertson (G4BJM)
installed the optional 250Hz filter. Performance was excellent, I never
had RX overload problems, even under contest conditions. My only
critisism was the QSK. Using an external keyer the transmitted CW was
clipped, many other rigs do the same. I compensated by increasing the
mark/space on the keyer. I later changed to a TS940S which has much
better QSK. I ran the two together for some months. The 751a was a bit
more sensitive on the higher bands. The 940 has more flexible filtering,
and mine has IRC filters which are excellent. However I doubt there's
anything I could copy on the 940 that I couldn't equally well on the
751a.
The QSK problem may be relevant to your amtor activities, I didn't try
it. Amtor works fine on the 940.
73 Fraser