[Premium-Rx] 590H Filters?

[Bill Mason]

To all:

I have tried to get information about the 590H from Harris...nada!!  They
won't even talk about it and will not give you any hints.  I have two of the
items and they are good receivers except for this "painus in the a_us."  The
unit was designed for frequency hopping service and its reputation indicates
it is well designed for this and most other services: it is also much
heavier than the 6790 RACAL series.  Frankly, I prefer RACALs over the
Harris but some people like Chevys and some like Fords.  I worked at Collins
(Dallas) way back in the Sixties and during that time made friends with many
people in the industry...some still at Harris and neither I nor any of my
friends from that period have been successful with Harris (collectively) in
getting the necessary information that would a allow a modification of the
receiver such that it will perform as Todd's acquaintance's.

Frankly that is not a bad way to proceed and If Todd could come by the
information in a more graphic form, I, for one, would give it a try...it
doesn't seem too hard at first blush!  

Bill
W5STP


-----Original Message-----
From: premium-rx-bounces at mailman.qth.net
[mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of
ToddRoberts2001 at aol.com
Sent: Sunday, January 04, 2009 6:22 PM
To: premium-rx at mailman.qth.net
Subject: Re: [Premium-Rx] 590H Filters?

In a message dated 1/4/2009 6:42:34 P.M. Eastern Standard Time,  
eugene at hertzmail.com writes:

"In the standard receiver, bandwidth values displayed on the front  panel
are selected on the A14 Assembly with DIP switch S2.  This switch  is not
used in the enhanced model ("H" model). Bandwidth values are fixed  (not
selectable) in the 590H Receiver, and are displayed for each  selected
demodulation modes as follows:
usb,lsb,isb - 3.2kHz
am -  6.0kHz
fm - 16.0 kHz
cw - 0.3kHz

I have always wanted to get more  filter choices in this radio
_____________________________________________________________
 
Hi Eugene,
I'm sure others know more about this but I would guess the filter
choices may be locked in by the factory programming of the 
eprom set and may not be changeable except by installing
another set of eproms with more filter choices.
 
I know someone who made up his own IF board for an RF-590
and used small 5V reed-relay switches to switch both the input
and output sides of the filters. He was able to improve the 
ultimate rejection (blowby) around the filters by using reed-relay 
switches instead of the diode switching the factory used.
 
He manually switched the filters by putting a small rotary
switch in the front panel where the squelch control was located. 
This way he could use any filter in any mode and not be locked
into a single bandwidth choice for each mode. For example he 
could switch in any filter choice in the AM or CW mode. He could also  use
different sizes and types of filters by making up his own IF board. 
 He could always restore the receiver back to original if wanted 
by re-installing the original IF board, removing the rotary switch and  
putting 
the squelch control back into place.
 
This may be more than you are willing to do but thought it
may give you some ideas on what is possible with the RF-590 
series.
 
73 - Todd WD4NGG
 
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