[Amps] Alpha 87 (not 87A)
wv2zow at gmail.com
Wed Nov 8 13:46:37 EST 2017
Gary: This will work for other stations, but not your own. Your own
signal is likely to be too strong for this test. --Mike, WV2ZOW
On Wed, Nov 8, 2017 at 1:21 PM, Gary Schafer <garyschafer at largeriver.net> wrote:
> The easiest way to observe splatter is to switch your receiver to the
> opposite side band and listen for the crud.
> Intermod products are generated on both sides of the signal. By listening on
> the opposite side band you eliminate your receivers filter bandwith from
> causing you false indications.
> On a good clean signal you will not hear anything on the opposite side band
> from that station.
> Gary K4FMX
>> -----Original Message-----
>> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Jim Thomson
>> Sent: Wednesday, November 08, 2017 10:44 AM
>> To: amps at contesting.com
>> Subject: [Amps] Alpha 87 (not 87A)
>> Date: Tue, 7 Nov 2017 15:14:43 -0500
>> From: Larry <pacer99 at aol.com>
>> To: jim at audiosystemsgroup.com, amps at contesting.com
>> Subject: Re: [Amps] Alpha 87 (not 87A)
>> <i just finished the CQ WW SSB and except for a very few stations the
>> quality of signals was good. i am using an Icom IC-7800.
>> <i believe that if each of us take the time to contact the offending
>> station and explain, in a polite manner that they were "spattering".
>> try to help them correct the problem. the bands would clean up rapidly.
>> every time that i do it the problem is solved and the <offending station
>> is grateful. no one wants to be rude to others. it's a friendly hobby
>> after all.
>> <complaining does no good.
>> ## For folks trying to measure the total BW of an SSB signal, remember
>> not to inadvertantly add the width of your RX filter...to the other
>> fellows TX bw. IE: say you are using a 3 khw wide RX filter..and are
>> on 3800 LSB. You will hear
>> everything from 3800...down to 3797. Meanwhile the offending station
>> is on 3797 LSB. Assume he is also TXing with a 3 khz filter. On
>> paper, he should be occupying 3797...down to 3794. You tune across
>> his signal, and you can hear
>> him from 3794....all the way up to 3800. You tell the fellow that
>> you can hear him.. 3 down...and 3 up from his TX freq of 3797. No the
>> fellow is not 6 khz wide, he is only 3 khz wide. You have added your
>> 3 khz wide RX BW to his
>> 3 khz TX BW to arrive at the 6 khz figure.... which is incorrect.
>> That mistake is done all the time. A better method would be to tune
>> across his ssb signal, using a pair of 500 hz cw filters..... sorta
>> like poor mans spectrum analyzer. In actual
>> practise, it works good. Then you will hear that he is only 3 khz
>> ## I wouldnt put any stock in the Icom fish finders either. They will
>> easily show a dead cxr as being 2 khz wide, and other erroneous stuff.
>> Also make sure your NB is OFF, and dont have excess RF gain applied.
>> Shut the RF rx pre-amp off, NB
>> off, and back down on the RFor IF gain control a bit..and also switch in
>> some RX padding, like 6 or 12 db. Then use a pair of 500 hz filters
>> if using a xcvr that has switchable RX CW filters, or the dsp eq....
>> then carefully tune across his signal,
>> using your MAIN RX. Meanwhile you can simultaneously listen on 3797
>> LSB... on your SUB RX. Then you can correlate asap, any splatter
>> products, while listening on your Main RX..with a pair of 500 hz cw
>> filters in left ear... while listening to him on LSB... on your right
>> ear....using the sub RX.
>> Jim VE7RF
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