I'm testing some 10/100 ethernet transformers and I need a 50:100 ohm
balun for 30 - 80 MHz. How do I make one? (I need to measure return
losses on the transformer. The spec is LT -18 db.)

I assume you want to measure them on a 50 ohm test system. A bit mathy, but
you could use a minimum loss T pad and include the pad's loss in the math...

For a transformer, ther turns ratio would be square root two...
--
Steve N, K,9;d, c. i My email has no u's.

wrote in message
...
I'm testing some 10/100 ethernet transformers and I need a 50:100 ohm
balun for 30 - 80 MHz. How do I make one? (I need to measure return
losses on the transformer. The spec is LT -18 db.)

Upon looking, I think the easiest thing to do is to buy a 50:100
balun. Something small with leads I can solder into a fixture. I found
one at TeleTech,model TT57E in a TO5 can.
On Tue, 29 Jun 2004 17:36:30 -0500, "Steve Nosko"
wrote:

I assume you want to measure them on a 50 ohm test system. A bit mathy, but
you could use a minimum loss T pad and include the pad's loss in the math...

For a transformer, ther turns ratio would be square root two...

wrote in message
...
Upon looking, I think the easiest thing to do is to buy a 50:100
balun. Something small with leads I can solder into a fixture. I found
one at TeleTech,model TT57E in a TO5 can.


Don't forget that it will factor into your measured data. Can't figure out
what "LT -18 dB" is...Loss Tangent doesn't make sense...

If what you want to measure is a return loss of -18 dB, then the transformer
you buy better be better than that and you'll have to measure it into the
100 ohm load and do the math if is near -18.
--
Steve N, K,9;d, c. i My email has no u's..

I knowand itstough finding onwith return lossless than -18 db. BTW: LT
-18 db,.I meant return loss is lessthan -18 db(or below -18db).
On Wed, 30 Jun 2004 11:42:00 -0500, "Steve Nosko"
wrote:


wrote in message
.. .
Upon looking, I think the easiest thing to do is to buy a 50:100
balun. Something small with leads I can solder into a fixture. I found
one at TeleTech,model TT57E in a TO5 can.


Don't forget that it will factor into your measured data. Can't figure out
what "LT -18 dB" is...Loss Tangent doesn't make sense...

If what you want to measure is a return loss of -18 dB, then the transformer
you buy better be better than that and you'll have to measure it into the
100 ohm load and do the math if is near -18.

Ahhhh! Gotit! LT = Less Than... I'da used ""

73
--
Steve N, K,9;d, c. i My email has no u's.


wrote in message
...
I knowand itstough finding onwith return lossless than -18 db. BTW: LT
-18 db,.I meant return loss is lessthan -18 db(or below -18db).
On Wed, 30 Jun 2004 11:42:00 -0500, "Steve Nosko"
wrote:


wrote in message
.. .
Upon looking, I think the easiest thing to do is to buy a 50:100
balun. Something small with leads I can solder into a fixture. I found
one at TeleTech,model TT57E in a TO5 can.


Don't forget that it will factor into your measured data. Can't figure
out
what "LT -18 dB" is...Loss Tangent doesn't make sense...

If what you want to measure is a return loss of -18 dB, then the
transformer
you buy better be better than that and you'll have to measure it into the
100 ohm load and do the math if is near -18.