Telamon wrote:
In article ,
"Mark S. Holden" wrote:


Telamon wrote: snip

I was also thinking of getting some better filters for it. What do
you recommend for program listening?


For AM mode I like a filtronetics marked 6.8khz that reads 6.1

For nice fidelity Sideband, I like a filtronetics marked 3.24khz that
reads 2.9

Both are crystal filters originally intended for the Racal 6790/gm.

They have very steep skirts, and the radio sounds beautiful with
them.


Is this them?
Filtronetics, Inc.
6010 Parretta Dr
Kansas City, Missouri 64120
UNITED STATES
Phone: 816-231-7375 (Ext. 335)
Fax: 816-241-0368

They don't appear to have a web site. Do you have part numbers on the
6.8 KHz filter? Another question is what did it take to install it in
the 7030+?


The web site is:

http://www.filtro.net/

I couldn't find the ones I have on their web site, so they may have been
done for a specific contract. Getting a non production bandwidth from
them may or may not be a big deal.

Back when I had the 6790/gm I ran into a small supply of the 3.24khz
symmetrical filters, and jumped on them because I love the 3.2khz
bandwidth on my Harris, and they're for a common IF frequency.

When I got the 7030+ I installed one. After seeing how well it
performed, I started hunting down 6790 filters suitable for AM. Along
the way I found the McCoy 6khz mechanical filter for the 6790 was an
impedance mismatch and wouldn't read.

I'll need to open up my radio to track down the part number for the
6.8khz filter - I've got an extra layer of case to deal with as my radio
is installed in an equipment case with battery packs and so forth to
make it "portable".

But I'll see if I can get it for you tomorrow.

I used some angle aluminum and flat stock to make a shelf for the
filters that sits on the inside back wall of the radio. AOR
thoughtfully provided nicely spaced holes for attaching it to the back
panel. I used stuff I had in stock.

The filters are on their side, and are held with velcro. I used RG174
to feed the terminals into the holes you'd solder extra filters into on
the main PC board.

I'll try to remember to shoot some pictures while I've got it open.

The reason these filters sound so good is they're a little wide with
very steep skirts. (1:1.33 on the sideband one)

Regards,

Mark