For ferrites commonly used in SWL baluns/ununs:
If you are using type 43 material in an RF transformer, performance will
fall off shortly after 10 Mhz. If the core is wound as a true balun/TLT
(Transmission Line Transformer), I have used it up to 30 Mhz.

Type 61 material is much more suitable for RF transformer from .2 Mhz to
100 Mhz. If wound as a true balun/TLT, it can be pressed into even
broader frequency service.

This page points out the above:
http://www.palomar-engineers.com/Fer...ite_cores.html

With iron:
Type 2, such as T106-2, when wound as an RF transformer is very
satisfactory to a bit beyond 10 Mhz. Wound as a true balun, I have used
it up to 30 Mhz. (it is really too lossy, for me, at 28 Mhz, 10m)

Type 6 material, such as T106-6, is good from 2-30 Mhz when used as RF
transformer (actually, I find the bandwidth to be larger in practice.)
If wound as a balun/unun/TLT, it is quite usable from MW to ~50 Mhz.
When wound as the 16:1/9:1 as I pointed out earlier, I find this to be
THE KILLER BALUN/UNUN (can be used interchangeably.)

This page points out the suitability of the material above:
http://www.palomar-engineers.com/Iro...on_powder.html

Regards,
JS

On 9/8/2010 2:29 PM, bpnjensen wrote:

...
I am primarily interested in SW listening, not amateur, and really 16
- 160 meters. Would you recommend Type 61 for this application?

Bruce Jensen

With SWL, the type 43 would work better at 160m and the 61 better at
17.48–17.90 MHz and above. But, the type 43 would work well on MW,
which I am assuming is of interest to you also. Antenna type,
inductance/performance you find necessary in rejection of CM, size of
the core, number of turns, etc. all factor in, also. Mainly, I am
tossing this stuff our for "nit pickers" like me ...

You could get by with either material ... one will favor the top end,
one the bottom ... but you can use either. Some might see the
difference between performance of the two as "splitting hairs." I just
go to extremes for fractions of s-unit, or db. LOL

Regards,
JS

On Sep 8, 10:49*pm, John Smith wrote:
On 9/8/2010 2:29 PM, bpnjensen wrote:

...
I am primarily interested in SW listening, not amateur, and really 16
- 160 meters. *Would you recommend Type 61 for this application?

Bruce Jensen

With SWL, the type 43 would work better at 160m and the 61 better at
17.48–17.90 MHz and above. *But, the type 43 would work well on MW,
which I am assuming is of interest to you also. *Antenna type,
inductance/performance you find necessary in rejection of CM, size of
the core, number of turns, etc. all factor in, also. *Mainly, I am
tossing this stuff our for "nit pickers" like me ...

You could get by with either material ... one will favor the top end,
one the bottom ... but you can use either. *Some might see the
difference between performance of the two as "splitting hairs." *I just
go to extremes for fractions of s-unit, or db. LOL

Regards,
JS

JS you are right most of the ready-made SWL Antenna
MLBs [UnUns] are build for and advertise 500 kHz to
30 MHz for both MW & Shortwave Bands coverage.

Frequency coverage 0.1 to 30 MHz
http://www.grove-ent.com/WR0130.html

Unsurpassed, 1 - 55 MHz Reception
http://www.grove-ent.com/ANT8.html

For Receive Only: 100 kHz to 40 MHz
http://www.universal-radio.com/catalog/sw_ant/1484.html

Frequency Range 100kHz to 30MHz
http://www.wellbrook.uk.com/pdf/UMB130m.pdf

182A Isolation Unit : 0.1 - 30 MHz
http://www.iceradioproducts.com/reco...age%20Matching

Coverage from 125 kHz thru 30 Mhz
http://cgi.ebay.com/180556245641

-versus- FT-140-61 Ferrite Core for coverage
from 100 kHz. to 150 Mhz
http://cgi.ebay.com/320573201259

~ RHF

On 9/8/2010 11:25 PM, RHF wrote:
On Sep 8, 10:49 pm, John wrote:
On 9/8/2010 2:29 PM, bpnjensen wrote:

...
I am primarily interested in SW listening, not amateur, and really 16
- 160 meters. Would you recommend Type 61 for this application?

Bruce Jensen

With SWL, the type 43 would work better at 160m and the 61 better at
17.48–17.90 MHz and above. But, the type 43 would work well on MW,
which I am assuming is of interest to you also. Antenna type,
inductance/performance you find necessary in rejection of CM, size of
the core, number of turns, etc. all factor in, also. Mainly, I am
tossing this stuff our for "nit pickers" like me ...

You could get by with either material ... one will favor the top end,
one the bottom ... but you can use either. Some might see the
difference between performance of the two as "splitting hairs." I just
go to extremes for fractions of s-unit, or db. LOL

Regards,
JS

JS you are right most of the ready-made SWL Antenna
MLBs [UnUns] are build for and advertise 500 kHz to
30 MHz for both MW& Shortwave Bands coverage.

Frequency coverage 0.1 to 30 MHz
http://www.grove-ent.com/WR0130.html

Unsurpassed, 1 - 55 MHz Reception
http://www.grove-ent.com/ANT8.html

For Receive Only: 100 kHz to 40 MHz
http://www.universal-radio.com/catalog/sw_ant/1484.html

Frequency Range 100kHz to 30MHz
http://www.wellbrook.uk.com/pdf/UMB130m.pdf

182A Isolation Unit : 0.1 - 30 MHz
http://www.iceradioproducts.com/reco...age%20Matching

Coverage from 125 kHz thru 30 Mhz
http://cgi.ebay.com/180556245641

-versus- FT-140-61 Ferrite Core for coverage
from 100 kHz. to 150 Mhz
http://cgi.ebay.com/320573201259

~ RHF
.

I have always wound my own. Some of those probably work well, I just
don't know. Winding all my baluns/ununs myself has given me a hands on
exposure to a multitude of core materials, winding techniques,
performance of the differing constructions, etc.

The core material I mentioned earlier, along with the winding technique
for it gave the best performance, across the widest bandwidth, of any I
have wound and used ... I am forever searching new techniques and
materials. Just ordered some russian toroids which look promising ...
when you span 30+ Mhz, performance on one end will not match the other
.... so the question simply becomes, "What is the best compromise?"

Regards,
JS

On 9/8/2010 11:25 PM, RHF wrote:

...
~ RHF
.

I should have mentioned, what I really love is when they chuck a
resistor into a box, maybe a coil, maybe a capacitor, maybe both, and
call it a "balun" and/or "unun." Just shows you how broad some peoples
definition/interpretation of what balun/unun means! ROFLOL

Regards,
JS

On 9/9/2010 12:02 AM, John Smith wrote:
On 9/8/2010 11:25 PM, RHF wrote:

...
~ RHF
.

I should have mentioned, what I really love is when they chuck a
resistor into a box, maybe a coil, maybe a capacitor, maybe both, and
call it a "balun" and/or "unun." Just shows you how broad some peoples
definition/interpretation of what balun/unun means! ROFLOL

Regards,
JS

I should have further mentioned, when you are having to insert 10db,
20db, 30db+ attenuators into the antenna line of a good antenna, to
prevent overloading of the receiver, you know you have a good balun/unun!

Regards,
JS

On 9/9/2010 10:05 AM, dave wrote:

...
50 Ohms is the characteristic impedance of RG58/U, the defacto standard
SWL cable. 50 Ohms is also the nominal impedance of the unbalanced
external RF input on virtually every receiver so equipped.

The hose rule says you can't feed water from a fat hose (Hi-Z) into a
hose of lesser diameter (Low Z) without spilling some. If you go the
other way, no spillage.

The point of the MLB is to keep the highest impedance from the antenna
at or below 50 Ohms.

I have 45 years professional experience in broadcast engineering. I used
to maintain the transmitter (3,800 KW ERP) broadcasting station in Los
Angeles. I know Magic T combiners and trombone phase adjusters.

Magic and technology are indistinguishable to the average mook.

Great. You just said everything I have been saying using different
words and phrasing ... kewl ability, knack, trick, ability ... there are
probably many levels you would like to take the discussion to in order
to obfuscate minds and impress idiots ... however, we are discussing
baluns/unun and you, your great accomplishments, your skills of being a
great father, etc. are of no interest to me, what-so-ever ... but hey,
others may like to hear it.

Regards,
JS

On Sep 9, 9:25*am, John Smith wrote:
On 9/9/2010 10:05 AM, dave wrote:



...
50 Ohms is the characteristic impedance of RG58/U, the defacto standard
SWL cable. 50 Ohms is also the nominal impedance of the unbalanced
external RF input on virtually every receiver so equipped.

The hose rule says you can't feed water from a fat hose (Hi-Z) into a
hose of lesser diameter (Low Z) without spilling some. If you go the
other way, no spillage.

The point of the MLB is to keep the highest impedance from the antenna
at or below 50 Ohms.

I have 45 years professional experience in broadcast engineering. I used
to maintain the transmitter (3,800 KW ERP) broadcasting station in Los
Angeles. I know Magic T combiners and trombone phase adjusters.

Magic and technology are indistinguishable to the average mook.

- Great. *You just said everything I have been saying using different
- words and phrasing ... kewl ability, knack, trick, ability ... there
are
- probably many levels you would like to take the discussion to in
order
- to obfuscate minds and impress idiots ... however, we are discussing
- baluns/unun and you, your great accomplishments, your skills of
being a
- great father, etc. are of no interest to me, what-so-ever ... but
hey,
- others may like to hear it.
-
- Regards,
- JS

Dave 'obfuscate minds' . . .

Dave 'impress idiots' . . .

not 'our' dave ;;-}} ~ RHF

In article ,
D. Peter Maus wrote:
On 9/8/10 16:29 , bpnjensen wrote:
On Sep 8, 10:30 am, John wrote:
For ferrites commonly used in SWL baluns/ununs:
If you are using type 43 material in an RF transformer, performance will
fall off shortly after 10 Mhz. If the core is wound as a true balun/TLT
(Transmission Line Transformer), I have used it up to 30 Mhz.

Type 61 material is much more suitable for RF transformer from .2 Mhz to
100 Mhz. If wound as a true balun/TLT, it can be pressed into even
broader frequency service.

This page points out the
above:http://www.palomar-engineers.com/Fer...ite_cores.html

With iron:
Type 2, such as T106-2, when wound as an RF transformer is very
satisfactory to a bit beyond 10 Mhz. Wound as a true balun, I have used
it up to 30 Mhz. (it is really too lossy, for me, at 28 Mhz, 10m)

Type 6 material, such as T106-6, is good from 2-30 Mhz when used as RF
transformer (actually, I find the bandwidth to be larger in practice.)
If wound as a balun/unun/TLT, it is quite usable from MW to ~50 Mhz.
When wound as the 16:1/9:1 as I pointed out earlier, I find this to be
THE KILLER BALUN/UNUN (can be used interchangeably.)

This page points out the suitability of the material
above:http://www.palomar-engineers.com/Iro...on_powder.html

Regards,
JS

I am primarily interested in SW listening, not amateur, and really 16
- 160 meters. Would you recommend Type 61 for this application?

Bruce Jensen



Bruce,

The Amidon website has a chart of ferrite materials and their
applicability to various project types. Most of your questions can
be answered there. Including options should you like to build
something specific to your needs, deviating from the intents of an
original design.

And if you're using the Amidon charts, use the line giving useful
frequencies for "broadband transformers". Most of the Amidon frequency
spec. is for tuned circuits, but for broadband use, you're using the
core at frequencies much higher than what the same material is used
for in tuned use.

The first longwire balun I built, inspired by the product review in
a WRTH used, I think, 45 material or something around there. (Not in
the mood to dig out that bag of stuff). It only worked above 15 Mhz,
so was fine for CB listening, but who wants to do that. The transformers
I've done since use the John Bryant recommended type 77, type 75, or
type J. They're good for the range I listen to, 5-17 Mhz and probably
reasonable below that.

Type 77 is speced for tuned use around .1-1 Mhz (as I remember), but
for using it in broadband use, you're trading off some core loss with
much smaller coil windings and the benefits that gives.

Not the same thing as transmitting, where you can accept a more limited
frequency range and don't want your core to melt, or expode, or get
saturated and go nonlinear at that power level.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

On 9/9/2010 4:20 PM, dave wrote:

...
I'm not here to impress anyone. I'm just hanging around waiting for the
rare moment when HAARP isn't screwing with 30 Meters and the sun's got
some acne. I monitor real time solar data, predicted propagation,
observed propagation, and atmospheric weather.

I drop in here every 20 minutes because I used to smoke.

Yeah, well, I think you are still smoking ...

Maybe it used to be tobacco, but gawd knows what it is now! LOL

Regards,
JS