Date: Tue, 17 Aug 93 04:30:07 PDT
From: Advanced Amateur Radio Networking Group <tcp-group@ucsd.edu>
Errors-To: TCP-Group-Errors@UCSD.Edu
Reply-To: TCP-Group@UCSD.Edu
Precedence: Bulk
Subject: TCP-Group Digest V93 #211
To: tcp-group-digest
TCP-Group Digest Tue, 17 Aug 93 Volume 93 : Issue 211
Today's Topics:
56kb links
JNOS 110x9 & trace
NOS-FAQ
rx IFs for 9600
subscrive
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----------------------------------------------------------------------
Date: Mon, 16 Aug 93 08:23:22 cst
From: kf5mg@vnet.IBM.COM
Subject: 56kb links
To: TCP-Group@UCSD.Edu
Can someone answer some 56kb link questions for me? Thanks. ( Is there
a active mailing list or FAQ that covers these questions? )
1). Is there more than 1, 56kb modem? If so what are they and what are
the pros and cons of each?
2). What is the output power of the 56kb RF modem?
3). Where can you get 440MHZ and 1.2GHZ transverters to interface to the
RF modems?
4). What equipment do you need to tune up the modem and transverter?
5). How do you interface the modem to the PC?
6). What's the typical cost of a 56KB link?
7). How does the cost compare to a 19.2KB link?
73's de Jack - kf5mg
Internet - kf5mg@kf5mg.ampr.org - 44.28.0.14
AX25net - kf5mg@kf5mg.#dfw.tx.usa.na - home (817) 488-4386
Worknet - kf5mg@vnet.ibm.com - work (817) 962-4409
------------------------------
Date: Mon, 16 Aug 93 11:12:28 EDT
From: "Jon Maguire redsox@vnet.ibm.com" <redsox@vnet.IBM.COM>
Subject: JNOS 110x9 & trace
To: TCP-group@UCSD.edu
I've noticed that when I leave my JNOS on the trace screen, when new mail
comes in via SMTP, I don't get notified of it when I PF10 back to the
command interpreter. I've also noticed this in earlier versions as well
(108d). If I'm sitting at the command prompt, the notification appears.
I do have SMTP QUIET NO set. Is this normal?
-----------
Jon Maguire N1CQE/4 | ibm-vm: maguire@sppvm1 usib2tfc@ibmmail
Advantis | Packet: N1CQE@KC4LDT.#CLW.FL.USA.NA
Dept NB4 / Bldg PAV | voice: t/l:438-3038 external:(813)-878-3038
3105 W. M.L.King Blvd.| fax : t/l:438-3922 external:(813)-878-3922
Tampa, FL 33607 | AMSAT #21847 TAPR #2916 TPALAN BARS
| Internet: redsox@vnet.ibm.com
| IP 44.98.0.136 N1CQE.ampr.org
------------------------------
Date: Mon, 16 Aug 93 17:39:34 EDT
From: "Jon Maguire redsox@vnet.ibm.com" <redsox@vnet.IBM.COM>
Subject: NOS-FAQ
To: TCP-group@UCSD.edu
Where is the latest NOS-FAQ stored? The one I have is dated 12/92.
-----------
Jon Maguire N1CQE/4 | ibm-vm: maguire@sppvm1 usib2tfc@ibmmail
Advantis | Packet: N1CQE@KC4LDT.#CLW.FL.USA.NA
Dept NB4 / Bldg PAV | voice: t/l:438-3038 external:(813)-878-3038
3105 W. M.L.King Blvd.| fax : t/l:438-3922 external:(813)-878-3922
Tampa, FL 33607 | AMSAT #21847 TAPR #2916 TPALAN BARS
| Internet: redsox@vnet.ibm.com
| IP 44.98.0.136 N1CQE.ampr.org
------------------------------
Date: Mon, 16 Aug 93 8:14:43 PDT
From: Glenn Elmore <glenne@hpsadl3.sr.hp.com>
Subject: rx IFs for 9600
To: tcp-group@ucsd.edu
ka7oei writes:
> I was wondering about the feasiblity of simply bypassing the 455 KHz filter
> and using the 10.7 MHz xtal filters in the first IF, or perhaps
> 'beefing up' the filters in the first IF. After all, the 10.7 MHz
> filters *are* relatively inexpensive AND readily available (Digi-Key, etc.)
>
> A few those monolithic 2-pole xtal filters (and a few caps) would probably
> do the job, unless you had some very strong adjacent channel signals...
> Wouldn't they?
>
Getting to narrow bandwidths with good stopband response early and
before a receiver has a lot of gain stages is generally a good thing.
However, I see two problems with trying modify radios as you describe.
For one, most crystal filters do not offer the kind of stopband
rejection and multiple poles or sets of filters would likely be
required. Also, many crystal filters have spurious responses a few
passbandwidths away from design center. I think this is particularly
true of higher frequency filters where an overtone is being used. The
result of using only a single crystal filter may be inadequate for
higher interference and hilltop environments.
Secondly, there is often a lot of gain in the 2nd IF. Removing the
filter entirely opens the detector up to a variety of problems. One
common one may be local AM broadcast stations causing limiting and
blowing away the signal. Here again, unwanted signals causing overload
and intermod can be pretty bad.
On a crystal controlled, phase modulated HT I modified, I bypassed the
455 filter and saw some of the above problems. It certainly did help
the BER though.
Thus far, I have contact information for A&A Engineering, purported to sell
10.7 MHz filters. I don't yet know of a source for wider 455 filters.
I'm still offering to put something together if a solid source of components
can be found.
Glenn Elmore n6gn
N6GN @ K3MC
amateur IP: glenn@SantaRosa.ampr.org
Internet: glenne@sr.hp.com
------------------------------
Date: Wed, 11 Aug 93 17:22:05 GMT
From: ik3ngu@ntt.glt.esercito.it. (Pasquale Pizzichetti)
Subject: subscrive
To: tcp-group@ucsd.edu
subscrive
ik3ngu@osi.iunet.it
------------------------------
End of TCP-Group Digest V93 #211
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