Bill,
In looking for something else, I found this $8 kit. It will do all that
your Tram sensor did, except work for the 200 or 2000 watts. I
recommend that you get this, build it, and then use it to test/exercise
your indicator. Then you can decide if you want to "restore" the
complete SWR meter.
http://www.kitsandparts.com/bridge.phpThe two connections between the remote sensor and the indicator are the
FWD (Forward) and REV (also called REF or reflected) signals. As the
indicator device is at heart a voltmeter, you can test this kit with a
simple voltmeter, then connect it to your indicator device as see how
that works.
It should let you know if the larger project of building the 2000 watt
capable sensor is of interest or of necessity.
Daniel KB3MUN
On 11/20/2012 00:35, smilingcat90254 wrote:
>
> I went to the photo page. The schematic is what you are calling to be
> the sensor I take it. Most everything is straight forward except for
> the toroidal inductor. drawings and photos are not readable enough for
> me to figure out exactly.
>
> The big problem is with the toroidal core. Material and dimension
> matters!! You may not be able to acquire the core. Did it call for
> Ferroxcube core? If it is, the company is still around and doing quite
> well. Can't make the part number or its construction on page 3. Yo may
> not be able to order directly but you should be able to find it at
> digikey.con or mouser.com Also check with your ham group/forum.
>
> The circuit is simple enough that you could get a perforated prototype
> board with pads
> (http://www.digikey.com/product-detail/en/8029/V2025-ND/1886431). Then
> mount the component, solder the components, and do a point to point
> solder connection.
>
> Two other parts which are going to be a problem are the two feedthru
> caps at the bottom. The trimmer capacitor shouldn't be too hard to
> obtain. The trimming capacitor on the upper left hand side is probably
> a mica based. Again ask around on your Ham group/forum on where to get
> such a thing. Modern electronics have moved away from using such a
> thing. New designs use active filters, more precise, stable and easier
> to tune.
>
> You definitely don't need a PCB made for this. The frequency also
> doesn't require to have a controlled impedance, so no worries there on
> how you wire the thing up (umm as long as you don't loop your hookup
> wires)
>
> Go to Ferroxcube and see if they still have the core. If they have it,
> just follow the instruction on the inductor note, build it exactly,
> then wire it up according to the schematic on the first page.
>
> Once you build it, you will need to tune it (adjust the trimming
> caps), and calibrate it.
>
> The circuit is fairly standard, so you might be able to find similar
> thing in ARRL handbook. It's got tone of good stuff.
>
> sincerely,
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Peter Johansson
> <rockets4kids@...> wrote:
> >
> > On Mon, Nov 19, 2012 at 7:07 PM, herpsrwe <herpsrwe@...> wrote:
> >
> >
> > > As stated in a previous post, I placed a photo I gathered on the
> internet,
> > > a Schematic, the required Inductor, and a Page from the Manual in the
> > > PHOTOS Section titled Tram / Diamond Corp ASM-1 SWR / RF Meter.
> >
> >
> > Is there something special about this piece of equipment? Do you have a
> > particular need for vintage equipment?
> >
> > You could probably purchase a new meter for less than it would cost
> to get
> > this one working and calibrated.
> >
> > -p.
>
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