Electronic Goldmine has some Pulse Engineering LAN transformers (same as
those used on many LAN boards) on clearance at $1.00 each.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G17078
Datasheet is at http://www.datasheet4u.com/download_new.php?id=541958
Quite cheap, in my opinion.
I'm not much further along then you but I did find a few things...
1) You can buy/salvage good quality 10.0 MHz transformers form networking
equipment designed for 10BaseT Ethernet. These are designed for galvanic
isolation and are used in old 10baseT routers and switches. Newer Ethernet
works a
If you want to see how to really do it right, check out this
distribution Amp
on the TAPR site.
https://www.tapr.org/kits_tadd-1.html
73, Dick, W1KSZ
On 11/26/2014 9:08 PM, Perry Sandeen via time-nuts wrote:
List,
I have seen on the net a 10 MHz filter using 10.7 IFtransformers but have
Perry,
Just three days ago, I posted about my using transformers from
Ethernet cards. I also summarized the results of some measurements
using the spectrum analyzer. There was only one response, so it seems
that what I posted was widely ignored.
Dave M - good find on Electronic Goldmine.
Joe Gr
Any suggestions as to which chips, or links to any documentation?
Thanks,
Jim
On 11/27/2014 11:36 AM, Chris Albertson wrote:
3) it is really easy to build a temperature controller using a $2 8-pin uP
and a few lines of code. The 8-pin uP will have a few analog inputs and
outputs and even pins l
Hi
Just as you can “move” 455 KHz IF transformers down with a little padding, you
can do the same thing with 10.7 MHz IF cans. They may or may not tune to 10
MHz. If you get some that don’t tune, it’s just a cap to bump them down.
The gotcha to any filter in a distribution system is Q. High Q
Hi
We are talking about many different parts here and calling them all
“transformers”.
The parts from an Ethernet line card are broadband devices used primarily for
isolation. The 10.7 MHz IF transformers are designed for use in a filter. The
first could be used to break a ground loop on a cab
I have 4 or 5 devices that use the 10 MHz from my Trimble Thunderbolt.
All but one have high impedance 10 MHz inputs, so the Thunderbolt
can drive the lot without any amplifier.
When I put together my Thunderbolt, power supply, and filter I assumed I
would
need a distribution amp ans made provis
For the most part, you don't want transformer isolation unless you plan on
using balanced lines. There are worse things than ground loops out there, and
lifting a coax shield away from ground is a great way to find all of them.
You definitely don't want 10.7 MHz IF transformers, unless you are
Hi
Even if you are running 50 ohm loads, with 4 outputs, a power splitter is a
very real solution. You will be down 6 db on each output. If you start with +13
you will have +7 dbm. Your target devices probably are happy as can be with
anything over +3 dbm.
-
If you are
Hi
You can also discover interesting things about the transformer it’s self in
some circuits. They do what they do, but they also bring along a new set of
issues. Sometimes simpler is better. If you don’t *need* what the transformer
does, why add more complications ?
If you don’t lift the gro
Yep. I found a lot of RF related issues appeared to go away when I switched
to double shielded cables, stopped using T connectors for distributing signals,
purchased and used HP distribution amps, terminated un used ports with 50 ohm
loads etc.
I also found ferrite cores applied on the outsid
Hi
If you are really going to get everything “tight” at RF, solid grounds
(properly done) and good shielding (well thought out) are going to do more for
you than a lot of messing with circuits. Common mode chokes (outside cores) are
way more likely to help than transformers.
That assumes you
John wrote:
For the most part, you don't want transformer isolation unless you
plan on using balanced lines. There are worse things than ground
loops out there, and lifting a coax shield away from ground is a
great way to find all of them.
You certainly need the shield grounded at RF, but y
Thanks for the kind words, Dick. :-)
However, a couple of notes on the TADD-1 bandpass filter:
1. I *don't* recommend installing it unless there is a good reason. As
others have noted, any tuned circuit is a thermometer and will degrade
ADEV performance. Other than the original test unit, I
No problem, always glad to be of help to those in need.
73 es HH, Dick, W1KSZ
On 12/2/2014 2:27 PM, John Ackermann N8UR wrote:
Thanks for the kind words, Dick. :-)
However, a couple of notes on the TADD-1 bandpass filter:
1. I *don't* recommend installing it unless there is a good reason.
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