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