Hi,

Well, the good news is I got it working.. Of course I have no idea what my
signal sounds like, haven't been able to make any contacts yet, but it runs
the thing and I know I at least keyed up a couple of repeaters. I'm pretty
sure this cable already has some sort of end on the wires, as I said they
are twisted together and there's a single point at the end, but I'm not
familiar enough to know what was done. maybe Tom can shed some light on
that? What I ended up doing was pushing the wire through the holes in each
screw, then turning it a bit so that the excess wire was also touching the
screw. Doing this, it allowed me to clamp it down without much wire sticking
out, really the only thing sticking out is that point at the end and even
then only by maybe an eighth of an inch, if that. I also made sure those
points were no where near one another.

The caps only thread out to a certain point, they won't come off completely.
As for the duty rating, I can only tell you that it was advertised as a 15
amp supply. Beyond that I'm not sure, it didn't say on the website. I've
seen more sturdy looking supplies, but hoping this one will do the job at
least for now. I definitely appreciate the info though, I can use all the
info I can get... Now off to learn the radio, but I'll definitely be
checking in.


-----Original Message-----
From: For blind ham radio operators
[mailto:[log in to unmask]]On Behalf Of Louis Kim Kline
Sent: Tuesday, December 19, 2006 6:14 PM
To: [log in to unmask]
Subject: Re: question about connecting a power supply


Hi Christy.

First of all, there is no shame in being a newbie because we all had to
start somewhere.  There are probably three things that you should take note
of.  First of all, is the current rating of the power supply heavy enough
for that radio.  That may be a problem, especially if you are relying on
the surge or intermittent duty current rating.  For FM equipment, it is a
much better practice to look at the continuous duty rating.  Intermittent
duty is ok for SSB because you are only drawing full current for brief
instances of time, generally on your voice peaks.  But FM is drawing full
current all of the time that you are transmitting.  I am not familiar
enough with your power supply to know whether it will or will not handle
the job.

Second, does your power supply have the type of binding post caps that only
thread out to a certain point, or do they thread off completely?

The third item, you've already taken care of--noting the polarity.

Generally, it is a good practice to put some kind of wire end on the wires
that will slide over the binding post.  That is partly because of the
tendency of the wire to slip off the post as you noted in your
message.  But an even more serious problem is the tendcy for a strand or
two to work loose from the post and touch the other post, thereby shorting
out the power supply.  That can be enough to destroy a poorly protected
power supply.

The type of binding post will govern what type of wire end is most
suitable.  If the cap doesn't completely unthread, then you could consider
one of two options.  The first, and probably the better option is to use
heavy duty spade lugs.  These are available in both crimp on and solder on
formats.  For low current devices, you can get away with crimp on, but it
is not advisable with devices drawing more thean 10 amps because at those
current levels, resistive losses start to generate a great deal of heat,
and voltage drops become significant.  Remember that if your connections
are getting warm, then you have lost power which will never be converted to
radio frequency energy.

The other option is to use banana plugs on the wires and fit them into the
holes on the binding post screw heads.  This is also not a good option for
high current divices, but can be a good option for HTs and QRP
requipment.  I don't think it would be a good move for the TMG707A, which
probably draws too much current.

If the binding post caps do thread off, then there is a better option
available--ring tongue wire ends, available from your local hardware
store.  Just be sure to get ones that are large enough to handle the
diameter of your wire.  The ones that Radio Shack carries are generally
badly sized for heavy current applications, but I bought a whole bunch of
nice ones at my local home improvement store.

The nice thing about the ring tongue wire ends is that there is no way that
they can slip off the binding posts and once the caps are cranked down they
make a very secure connection.

I use these throughout my station, and as long as the wire is well soldered
to the ends, they are extremelyreliable.  You can probably even crimp these
on for a short period of time to get on the air, but you probably want to
get someone to solder them at your earliest opportunity.

One last thought.  If your power supply is the 10 amp one that Radio Shack
sold a few years ago, that is the one with the binding posts on the front
and the cigarette lighter socket on the front, then I would caution you
that the filtering on that supply is less than great.  My sister used two
of those supplies and had a lot of trouble with hum until she finally
replaced them with Astron supplies.  If that is not the model you are
using, then I apologize for any moment of panic that I might have
caused.  I haven't paid as much attention to Radio Shack's latter ham radio
products, so it's entirely possible that you've got a model of power supply
that I've never had any experience with.

I hope this info is helpful to you.

73, de Lou K2LKK


At 04:20 PM 12/19/2006 -0600, you wrote:
>I posted this privately to someone, but thought perhaps it might work
better
>to post it here, even if I do feel like a complete newbie doing so..
>
>Ok, being as I've never hooked up my own power supply before--when I was
>active before it was just on an HT.. I thought I knew what I was doing, but
>it's not working the way I'd expected. the kenwood 707a came in yesterday,
>and the power supply today. So now the challenge of connecting the two..
>
>I got a radio shack power supply, 13.8vdc as recommended by the manual, 15
>amps. The terminals on the front of it look kind of like knobs on a radio
or
>something, they have big plastic covers that you use to screw and unscrew
>them. When unscrewed, I managed to reach down and feel the actual screw,
and
>each screw has a hole in it that goes all the way from the top of the screw
>to the bottom. the knobs have holes in them too, going front the back.
>
>As far as the radio DC cable, each has what feel like several very small
>bare wires at the end, but the wires have been twisted together and
sawtered
>at the end, so it's more like a single wire at the end of each, positive
and
>negative. they are labeled, so I know which is which, and I know which
>terminal is which on the power supply. Of course, everything is unplugged
as
>I'm trying to connect them.
>
>So, the first thing I tried was sticking the wires from the radio into the
>holes on the knobs. this didn't work, because rescrewing the knobs still
>didn't hold the wires in place. Next I tried wrapping the wires around the
>correct terminal, around the screw itself then screwing on the knobs. this
>sort of worked, but as it started to clamp down, the knob part started
>pushing the wires away rather than holding them in place. Is there a
certain
>trick to this? Should I be feeding the wire into the middle of the screw
>where there's a hole first, then wrapping it? I just don't want to
>experiment too much because I don't want to damage the cable. On the other
>hand, I sure don't want to do it wrong and create a worse problem. I'm
>looking into getting some eyes over here, but finding someone with
knowledge
>of these things is far from easy, especially when I can't get on the air
>anywhere except echolink, and I'm not sure which repeaters are close to me
>that also have echolink access.
>thanks!
>--
>Internal Virus Database is out-of-date.
>Checked by AVG Free Edition.
>Version: 7.1.394 / Virus Database: 268.10.1/390 - Release Date: 7/17/2006

Louis Kim Kline
A.R.S. K2LKK
Home e-mail:  [log in to unmask]
Work e-mail:  [log in to unmask]
Work Telephone:  (585) 697-5753


--
Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.1/390 - Release Date: 7/17/2006


--
Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.1/390 - Release Date: 7/17/2006

--
Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.10.1/390 - Release Date: 7/17/2006