That coupled with the fact that the receiver probably doesn't have an

exact 50 Ohm input Z, and of course the loop antenna Z is very likely to

change over a fairly wide range anyway. So I sure wouldn't worry about

some mismatch.

I have a similar setup here where I have an 88 Foot long dipole fed with

ladder line (the best I can do here). It feeds an oversized 2KW 4:1

balun (oversized to minimize heating losses from changing the balun

characteristics) before hitting the transmatch (MFJ949E). The balun is

primarily there for balanced feed as I realize the impedance varies a

great deal over the 3.5-29MHz range I use it. But it DOES perform very

well on all HF bands (and I've even used it on 6M too). I've tried MANY

different HF antennas in this Mobile home park (NO real estate space to

speak of) and this one outperforms everything else I've tried.

Yes, some verticals were a bit better on DX (especially a Butternut HF2V

I tried on 80/40), but their noise was WAY too high here.

So, I'd suggest just trying whatever matching ratio you have and see

what works best for you overall.

73 de Phil, KO6BB

http://www.qsl.net/ko6bb/ (Web Page)

RADIOS:

Grundigs: S-350 (2006)& G6 (2011).

Icom: R-75 with Cascaded 250Hz CW Filters.

Kenwood: TS130S HF Transceiver (circa 1980).

Radio Shack: DX-380 digital portable (circa 1990).

Zenith: Royal-7000 Transoceanic (circa 1969).

Audio Interface: Two Mark One Earholes.

Decoder Software: Gray-matter between two ears.

ACCESSORIES: Homebrew LF-MF Pre-Amp, MFJ-949E HF Tuner

Homebrew 6 Hz Audio Filter.

ANTENNAS: 88' Long Ladder-line fed dipole at 35 feet AGL.

Ratzlaff 3 Foot Active Whip at 36 Feet AGL for LF/MW

4 Foot/side Tuned Rotatable Loop at 15 Feet AGL for LF

Merced, Central California, 37, 18, 37N 120, 30, 6W CM97rh

On 3/8/2013 5:02 PM, John Popelish wrote:

> On 03/08/2013 02:45 AM, ceo@... wrote:

>> I'm using http://www.mingtek.tw/pdf/B-4.pdf

>>

>> 100Î© balanced fed into pins 14 and 16

>>

>> 50Î© output to R8 from pin 1

>>

>> pins 4 and 13 grounded

>>

>> Feel free to tell me I got it all wrong, I would not be

>> at all surprised.

> Transformer (and balun) impedance ratios are proportional to

> the square of the turns ratios. Using only half of a

> winding reduces the impedance by a factor of 1/4.

>

> In concept, since a 1:2 impedance ratio requires a turns

> ratio of 1:sqrt(2), that impedance ratio can be only

> approximated.

>

> A turns ratio of 3:2 gives an impedance ratio of 9:4 or

> about 100:44.44.

>

> A turns ratio of 4:3 gives an impedance ratio of 16:9 or

> about 100:56.25.

>

> A turns ratio of 5:3 gives an impedance ratio of 25:9 or

> about 100:36.

>

> A turns ratio of 5:4 gives an impedance ratio of 25:16 or

> about 100:64.

>

> etc.

>