[ICOM] 751 Vs. 751A

[Adam Farson]

Hi Hsu,

In 1994, I measured reciprocal mixing noise on my 751A and 781. The 781 was
significantly better in that area because of its DDS synthesiser.

Cheers for now, 73,
Adam VA7OJ/AB4OJ
 

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Hsu
Sent: 16-Feb-11 18:00
To: ICOM Reflector
Subject: Re: [ICOM] 751 Vs. 751A

Hi Adam,
   I found this test  data:  http://www.sherweng.com/table.html

It told me that IC751A's Lo phase noise is -127dbc/Hz, very good result.
  But in my experience, the 751A seems a noisy reciver.My friend modify this
receiver, very good result.
I guess the noise due to DC-DC converter.
         73!Hsu
----- Original Message -----
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Thursday, February 17, 2011 2:30 AM
Subject: Re: [ICOM] 751 Vs. 751A


> Hi Dick,
> 
> Both the 751 and the 751A have a PLL synthesiser which has fairly high 
> phase noise by current standards.
> 
> Cheers for now, 73,
> Adam VA7OJ/AB4OJ
> 
> 
> -----Original Message-----
> From: icom-bounces at mailman.qth.net 
> [mailto:icom-bounces at mailman.qth.net] On Behalf Of Dick Flanagan
> Sent: 16-Feb-11 09:01
> To: ICOM Reflector
> Subject: Re: [ICOM] 751 Vs. 751A
> 
> I heard from somewhere (check with Adam) that the 751A was practically 
> an complete re-design of the 751, ending up with a much better radio.
> 
> Dick