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1994-11-13
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Date: Sat, 23 Apr 94 04:30:06 PDT
From: Info-Hams Mailing List and Newsgroup <info-hams@ucsd.edu>
Errors-To: Info-Hams-Errors@UCSD.Edu
Reply-To: Info-Hams@UCSD.Edu
Precedence: Bulk
Subject: Info-Hams Digest V94 #447
To: Info-Hams
Info-Hams Digest Sat, 23 Apr 94 Volume 94 : Issue 447
Today's Topics:
amcomm s225 and yeasu ft23
ICOM 720 SERVICE MANUAL NEEDED
Illinois Scan Ban Proposed
Mac HyperTerm <> Ham TX/RX
Missing: Good HF Propagation
Send Replies or notes for publication to: <Info-Hams@UCSD.Edu>
Send subscription requests to: <Info-Hams-REQUEST@UCSD.Edu>
Problems you can't solve otherwise to brian@ucsd.edu.
Archives of past issues of the Info-Hams Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/info-hams".
We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party. Your mileage may vary. So there.
----------------------------------------------------------------------
Date: Tue, 19 Apr 1994 11:02:44 -0400
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!math.ohio-state.edu!news.acns.nwu.edu!ftpbox!mothost!lmpsbbs!NewsWatcher!user@network.ucsd.edu
Subject: amcomm s225 and yeasu ft23
To: info-hams@ucsd.edu
In article <kthompso.57.000D9A2B@WichitaKS.NCR.COM>,
kthompso@WichitaKS.NCR.COM (Ken Thompson) wrote:
> First a question about the amcomm s225.
> This is a mobile unit from the mid-'70s.
> Recv seems ok but the TX is off by +2.8kHz.
> I have the schematics but it is an unusual design.
> Anyone have any experience with this model or
> willing to make some suggestions if I send a copy of the schematic?
And I thought I had the only remaining S2-25! The transmit frequency can
be adjusted by removing the top and bottom covers and adjusting the large
piston trimmer capacitor mounted vertically on the bottom PC board. Two
notes of caution are in order: First, you MUST use an insulated or non-
metallic tuning tool for this adjustment. Second, this adjustment is also
temperature sensitive, so do not leave the covers off very long before you
make the required adjustment.
As an alternative, since you know you are 2.8 kHz high right now, remove
the covers and power up the radio for at least one hour on the bench. Pick
any channel and measure the transmit frequency as it sits, running into a
dummy load of course. Then adjust the trimmer to lower the frequency by
2.8 kHz and button everything back up. I ended up drilling a small hole in
the cover so I could tweak the frequency without removing the housing.
This rig uses a novel synthesizer operating on the receiver injection
frequency and a heterodyne exciter to put the transmitter on the proper
operating frequency. There are no easy mods for out-of-band, but it does
have entire 144-148 band coverage in 5 kHz steps, which was FAR ahead of
its time. The receiver is quite good for local packet, and it will receive
9600 baud without modification since it uses fairly wide filters. The
CA3089
limiter/detector IC (now obsolete) should NOT be replaced with the CA3189
substitute if you are running 9600. I took the top of the volume control
out
on the 6-pin DTMF encoder socket to provide a separate packet TNC
connector.
>
> Second I would like to investigate a noise problem on transmitted audio from
> the ft-23 while using an external mike. Does anyone have a service manual
> and/or schematic of which they would be willing to send copies?
>
> Ken.
If I remember correctly, this unit does NOT mute its internal microphone
when the external mic is plugged in. The only cure in this situation is to
cover the internal microphone or disconnect it completely from the circuit.
If you put the HT in your pocket, the noise of the fabric rubbing across
the grille will drive listeners batty; if you use a leather belt case in
a noisy area, the radio picks up the local noise on the internal (open)
microphone and seriously degrades your audio. Good Luck
--
Karl Beckman, P.E. < STUPIDITY is an elemental force for which >
Motorola Comm - Fixed Data < no earthquake is a match. -- Karl Kraus >
The statements and opinions expressed here are not those of Motorola Inc.
Motorola paid a marketing firm a huge sum of money to get their opinions;
they have made it clear that they do not wish to share those of employees.
Amateur radio WA8NVW @ K8MR.NEOH.USA.NA NavyMARS VBH @ NOGBN.NOASI
------------------------------
Date: 21 Apr 1994 15:34:33 GMT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!utnut!torn!news.unb.ca!nbt.nbnet.nb.ca!ve1fc.nbnet.nb.ca!ve1fc@network.ucsd.edu
Subject: ICOM 720 SERVICE MANUAL NEEDED
To: info-hams@ucsd.edu
Need an ICOM 720 A service manual in the worst way ...
I have a radio, which is in very bad condition and need the service manual
to get it up and running.
Appreciate any replys.
by the way ICOM America does not have one, so they say....
RGDS & TNX
Graham
ve1fc@nbnet.nb.ca
------------------------------
Date: Tue, 19 Apr 94 18:43:37 -0600
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!math.ohio-state.edu!news.acns.nwu.edu!news.eecs.nwu.edu!fidogate.nuars.nwu.edu!nwugate.fidonet.org!f747.n115.z1.fidonet.org!Jerry.Smith@network.
Subject: Illinois Scan Ban Proposed
To: info-hams@ucsd.edu
Here is a couple of key addresses to voice your opposition to Illinois
House Bill 4180, the proposed banning of DC powered scanning equipment.
Tom Cross is the Representative proposing this bill.
Illinois Rep. Tom Cross
541 Countryside Shopping Center
Yorkville, IL 60560
2138 -O Stratton Building
Springfield, IL 62706
-------------------------------
Illinois Govonor Jim Edgar
State Capitol
Springfield, IL 62706
-------------------------------
Representatives for your district may be found by calling your local public
library.
* * NON-RESIDENTS OF ILLINOIS...Your input is just as important. If this
law is passed, this may give YOUR representatives to propose laws similiar
to this in your state. Please send your letters to the above two
individuals.
Jerry
------------------------------
Date: Thu, 21 Apr 1994 15:12:03 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!pipex!demon!news@network.ucsd.edu
Subject: Mac HyperTerm <> Ham TX/RX
To: info-hams@ucsd.edu
Hello All,
I have an interest in amateur (Ham) radio. As such I have been using HyperTerm
to create a HyperCard stack which will allow me to control a Shortwave
transmitter via it's RS232 interface.
In order to turn off several of the transmitter's functions I need to be able
to send the "NULL", character ($00) from HyperTerm to the transmitter. I cannot
seem to be able to get HyperTerm to do this.
Anyone any ideas ?
Regards, Sean.
------------------------------
Date: Thu, 21 Apr 1994 14:42:07 GMT
From: ihnp4.ucsd.edu!usc!cs.utexas.edu!utnut!utcsri!newsflash.concordia.ca!canopus.cc.umanitoba.ca!tribune.usask.ca!kakwa.ucs.ualberta.ca!gov.nt.ca!ve8ev@network.ucsd.edu
Subject: Missing: Good HF Propagation
To: info-hams@ucsd.edu
MISSING PROPOGATION FOUND!
HF propogation reappeared over the last two days.
Was last seen moving over the North Pole and down the west coast
and into the South Pacific. Grab it while it lasts!
de VE8EV
------------------------------
End of Info-Hams Digest V94 #447
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