From: "Dave, AA6YQ" <dhb@mediaone.net>
To: <W8JI@contesting.com>
Copies to: "'amps'" <amps@contesting.com>
Subject: RE: [AMPS] IMD & Phase noise
Date sent: Thu, 3 Jun 1999 19:48:54 -0400
>
> Icom Japan's position is that their engineers are all fully occupied on
> new designs.
IMO, they should spend an hour or two and fix the present ones.
When I asked them why they didn't fix the software in the 706 so
the QSK worked, they said "no one cares about CW". I wonder
how we might get their attention to correct operation on virtually
unused modes like CW?
> When the problem was first discovered -- back in 1996 -- Icom America
> retrofitted some additional VFO shielding, which eliminated the transmit
> spur on the lower bands. Lacking a spectrum analyzer, I didn't discover
> that this fix was ineffective on 15m and above till a few months ago. With
> a 1500 watt amplifier and a 1khz split on 12m, locals reported my spur on
> the DX frequency at S9; so much for that pileup. The spur can be avoided
> by using XIT instead of split; QRO CW ops using 775s in high band pileups
> should keep this in mind.
Mine was a late model, with all mods. It had both the TX problem
and RX problem on 160 meters. When I was 20-40 dB over 9,
people reported my spur was S5-6 with a 4 kHz split.
I measured about 50 dB of attenuation at 4 kHz spacing on 160
meters. IMO, people should not use the 775 for split VFO
operation, and they should ALWAYS park the unused VCO on a
different band even if they have no intention of ever selecting it.
I can hear one W4 in VA on 160 meters on the JA frequency (1908-
1912) when he calls JA's working split (the W4's TX frequency
generally around 1825). When he uses his Kenwood the problem
vanishes, and his 775 was brand new last winter.
73, Tom W8JI
w8ji@contesting.com
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