As an owner of a ICOM 746 with INRAD CW filters for a second radio , I can
tell you mine hears what appears to be key clicks on ANY strong CW signal.
I attenuate the signal by 10 or 15 dB and that "cures" the problem.
Furthermore, I've noticed that a signal with clicks can be "cleaned up" if
another strong signal appears just below the nose of the I.F filter. I
suspect the AGC is reducing the gain and this results in what suddenly
appears to be a clean signal where before there was clicks. We can only use
the 746 as a multiplier radio because of this shortcoming. The 746 would
not live here if it were not so damn good on 2 meter weak signal. I sure
wouldn't put much faith in an observation made with this radio. Look at the
numbers for the receiver as tested in the ARRL lab and you will see the
shortcomings of the 746.
The stations listed were probably a bit above S9 at the QTH of Mr.
Anonymous. Sure wish he had a bit better receiver when making these
observations. I'm certainly not saying clicks were not there on the listed
stations, but I am saying the 746 is a poor platform to use when making
observations and conclusions.
----- Original Message -----
From: "Bill Fisher W4AN" <email@example.com>
Sent: Tuesday, March 06, 2001 5:14 PM
Subject: [CQ-Contest] Clicks (long)
> K1AR asked me to post this so you guys would quit picking on him and move
> the conversation to something controversial that didn't include him.
> I have noticed what I'll call key clicks are getting worse and worse
> on the bands. Normally, this phenomina can be observed when signals are
> VERY strong. The same signal that produces clicks at 40 over S9, will
> appear "clean" at S9.
> I made a post to CQ-Contest about this subject and received a few messages
> that suggested that receivers were the problem, and not transmitters. I
> did get one message from a European who happened to take some time on
> Sunday of the ARRL DX CW contest to make note of offending stations he
> found on 10 meters. This station was using an Icom 746 with 500hz filters
> in both IFs, and his noise blanker was turned off. No noise reduction or
> DSP was used either. Antenna was a 5 element mono band yagi at 33'. He
> noted that the band was "quiet" with many loud signals.
> I took his list of callsigns (he prefers to remain anonymous) and asked
> for rig types from the stations he noted as having the problem. Here is
> the list:
> CALLSIGN RADIO AMP QSK PTT VOX
> W4AN FT1000MP AL-1500 N N Y
> K2UA FT1000MP AL-1500 N Y N
> K1ZZ FT1000MP L7 ? ? Y
> K9NS FT1000D Henry 3K ? ? ?
> W4ZV FT1000MP LK800 N N Y
> K1AM TS940 Alpha ? ? ? ?
> KR1G FT1000MP Acom ? ? ?
> K1KI FT1000MP Alpha 86 N ? ?
> KC1XX IC-781 AL-1200 N N Y
> K3LR IC-781 KS9K HB N N Y
> vE3EJ IC-775 Alpha 87a N N Y
> W4KZ FT1000MP Alpha 78 N N Y
> W4MR FT1000MP AL-1200 N N Y
> N3RD FT1000MP Acom N N Y
> W3LPL FT1000MP 3-1000 HB N Y N
> UA3AB FT1000MP MKV Acom N Y N
> KR1G FT1000D Acom N N Y
> W3PP FT1000MP TenTec N N Y
> NA4K IC-765 & 1000mp none N N Y
> HG6N FT990 HB N Y N
> KB1H FT1000MP MKV Alpha 77 ? ? ?
> K4WI FT1000D Alpha 86 ? ? ? ***
> W4NF FT1000MP Alpha 374A ? ? ? ***
> K1XM FT1000MP AL-1200 ? ? ? ***
> K3CR FT1000MP AL-1200 ? ? ? ***
> K3NM IC-775 or 765 Titan or HB ? ? ***
> K5RX TS950 Alpha 89 ? ? ? ***
> KG9X FT1000MP none ? ? ? ***
> K9MA FT1000D AL-82 / SB220 ? ? ***
> K8AZ FT1000MP's 8877's ? ? ?
> N4AO FT1000MP MKV Titan N Y N
> *** - rig type found from contester station database.
> There were a few calls I could not find rigs for and they include: HA3A
> HA4FF, HA5MK/7, HG6N, HG8Z, K5YAA, LY5W, N2LT, RZ3A, S52ZW and SP8NR.
> The reporting station said there were plenty of loud stations with clean
> signals that he did not note. He said one of the loudest with a clean
> signal was K1EA (IC-781).
> 77% of this group using Yaesu FT1000X radios.
> I have always said the IC-775 and Kenwood TS940 were problematic in this
> regard, and if I include them in the list the number becomes 87%.
> Note that not a single TenTec radio is mentioned (Tom Rauch recently
> tested an Omni and told me that it was the cleanest modern day transmitter
> he has tested).
> Also note, no tube type radios.
> At this point you might say to yourself "Well probably 75% of the
> contesters out there are using FT1000X radios". Maybe! So I ran a poll
> on contesting.com asking for what type of contest radios people were using
> on HF in CW contests. http://www.contesting.com/survey/35 The results
> reveal that of the people who responded (796), only 32% of them were using
> FT1000X radios. Another 6% using the TS-940 (another offender). 12% are
> using TenTec radios.
> Worthless Information?
> Maybe this doesn't mean anything. Maybe the people who are loud enough to
> produce big signals on 10 meters in Europe are also the same people using
> FT1000X radios. Maybe the people responding to the survey spend more time
> answering surveys than they do operating the radio. I don't know. I am
> just presenting this information for discussion.
> What next?
> I would like to see a number of stations using "good" receivers in the WPX
> contest in May to make note of stations they observe clicking. One person
> who's opinion I respect highly said that he has noticed that listening on
> a IC-781 will be clean when a FT1000MP isn't on the same frequency. So
> observations should be done using a radio not prone to overload (IC781,
> R4C, TS830, TS930, TS850).
> Solving this problem
> N7DD posted a possible solution to this problem on the TopBand reflector
> which can be reviewed at
> I plan to try to fix my FT1000MPs if possible. I hope the rest of you
> will do the same.
> Bill Fisher, W4AN
> PS: I didn't run spell check on this message. Please send your english
> comments to my mom so she can say "I told you so" then next time I talk
> to her on the phone.
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