[TenTec] InRAD 2.1 kHz Filter for the Argonaut 509(The Argo from Hell)

[Tommy]

Richard,

Good luck with your 'project' and I sure hope Steve's great donation 
to your cause is fruitfiul for you .

Yes, I bought Elcrafts broadband noise source and their 7.044MHz 
signal oscillator, and then bought SpectraGram. Both provide 
excellent results. With the 7.044MHz signal oscillator, among other 
things, allows you to set the Orion's 250 and 500 hz filters smack 
on center frequency; it takes the guesswork out!. Since Spectragram 
is looking out a rig's audio, it doesn't care what rig furnishes it 
audio. I used it to check out filter shapes (with the broandband 
noise source) on my Omni 6, Omni 6 Plus, Orion, and now my IC-781. 
To me, they are  extremely useful tool's which takes a lot of the 
'guess work' out of finding out how your filters and your audio 
section is performing. Spectragram's use is only limited by your 
imagination...all in all, a very useful tool.

Tom - W4BQF

"So you have enemies?
Good.
That means you have stood up for something,
sometime in your life."
--Sir Winston Churchill--

----- Original Message ----- 
From: "Richard Arland" <richard.arland at verizon.net>
To: "Ten-Tec" <tentec at contesting.com>
Sent: Tuesday, December 21, 2004 9:46 PM
Subject: [TenTec] InRAD 2.1 kHz Filter for the Argonaut 509(The Argo 
from Hell)


Gang:

Steve Wilson, XE1UFO, graciously provided what I thought was 
supposed to be an Argo 505 (his first rig) as a parts rig for me to 
cannabalize to get "The 509 From Hell" back on the air. It arrived 
today. Boy! Was I surprised when I opened Steve's box and found not 
a 505 but a 509 instead! Granted it was in pretty rough cosmetic 
shape, but it was a 509 and that means I can swap some boards out in 
an attempt to get "The 509 >From Hell" to work on 10M.

For those of you who have forgotten (or have tried to forget) the 
last installment, I have managed to swap out all the transistors on 
the OSC board with 2N2222As in metal cans. Garland Jenkins from the 
T-T Lab graciously provided a new 10M coil and a T-1 transformer 
(doubler/tripler) coil along with several of the orange plastic dial 
pointers that were damaged in the original order during shipping. 
Thank you, Garland!

I substituted the coils and got the doubler/tripler to work as it 
should, but the rig still won't take off and oscillate on 10M, 
indicating that the switch wafers are either badly damaged or not 
making proper contact. Thanks to Steve's generousity I now have the 
ability to swap out the entire oscillator PCB from Steve's old rig, 
OR I can remove the switch wafers from Steve's old rig and put them 
into mine. Either way I end up with a way to check out the final 
stumbling block in getting "The 509 From Hell" to work on 10M.

More on this as soon as I can catch my breath and get a chance to 
pop open Steve's old rig and pull the OSC board. God willing, I 
might have a 100% functional 509 by the first of the New Year.

Now....for the real reason I started this posting................

Has anyone out there ever used an International Radio (InRAD) model 
752 xtal filter in an Argo 509? This xtal filter is made for an IF 
Freq of 9001.5 kHz. It is a 2.1 kHz wide, 8 pole xtal filter on a 
small PCB. There are four (4) pins on the PCB. I have no other 
information or installation instructions. My Argo's IF filter is the 
stock 4 pole, 2.8 kHz 9Meg filter comprised of four (4) individual 
xtals soldered into the SSB Gen board (P/N 80131). On all the 
previous 509s I done the IF filter swap on, they have all had the 
four xtals mounted on a small PCB that sat piggy back on the top of 
the SSB Gen board.

HELP!!!! I need some info as to how to correctly (the operative 
word, here) make the swap and will I need to realign the IF or SSB 
Gen boards once I do the swap?

I am anxiious to do this mod with this  particular xtal filter as it 
should really make an improvement in the Argo's receive specs. 
Speaking of which, has anyone ever tried using a wide band noise 
source and a program called Spectragram to map out the stock filter? 
The usual "mod" entailed swpping the 4 pole stock filter with a T-T 
8 pole 2.4 Khz xtal filter. I would be interested in finding out the 
quantitative difference in doing this mode. Has anyone tried this 
todate?

73 and thanks for allowing me to utilize all the bandwidth

Merry Christmas

Rich K7SZ

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