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Hi All,

Well I do have a Softrock Ensemble II LF ordered and eagerly awaiting it's arrival (being built by Tony Parks).? Over the years I've had a number of Softrocks, built most of them myself.? But at 78 eyes are a bit older and I don't think I'm the sharpest knife in the drawer any longer ;-)? Also, it's been awhile since I used a Softrock but figured that since I sold my Perseus it'll help fill in the gap in chasing/recording NDBs (my primary use for one).

I DO know that I always used a pair of transformers between my Softrock and the external soundcard.? My external soundcard of choice has traditionally been the "Ultimate USB Audio 2.0" with a 24 bit/192kHz response.? It's noise floor is supposed to be -108dB, not sure how that compares to others, but is more than good enough as any time I connect an antenna the existing noise floor rises, a good test to see if the receiver is the limiting factor.

Any-who, it's been so many years since I built my last setup that I forgot which transformers I used (to keep the center spike down).? I do know they were little red Triad units, I think 600/600 Ohms and was checking the Mouser catalog.? It seems that the frequency response of most that they have are 300Hz-100kHz. It seems that if I want to use the full range of the sound card (192kHz) I'd want transformers with more than a 100kHz upper limit, but like I said, it's been so many years that I've forgotten probably 90% of what I knew (been working with Electronics since around 1953).

QUESTION:? If you were ordering a pair of transformers, what would you buy, and where???

--
<>< 73 From "The Beaconeer's Lair" ><>
Specializing in DXing NDBs (Longwave Beacons)
Phil, KO6BB,

RADIOS:
YAESU: FTDX-101MP Xceiver, Dual SDR Receivers (~2020)
YAESU: FTDX-3000 Xceiver, DSP IF, 300Hz Roofing filter (~2019).
Icom: IC-718 Xceiver, DSP.
Uniden: SDS-200 Scanner, 25-1300MHz (2020)
Portables: Eton Elite 750 (2), AKA Grundig Satelite 750 (2020)
Sangean ATS-909X2 (2021), Tecsun PL-990 (2021)
ACC: MFJ-993B Auto Antenna Matcher.
HOMEBREW 4 Port Antenna Multicoupler, Feeds 4 RX's.

ANTENNAS: 88 foot Long Ladder-line fed dipole, ~35 feet AGL for MW/HF.
Top Loaded Tee (Dipole fed as single element) ~35 Feet AGL.
Butternut HF-6V 6 Band Vertical, ~12 Feet AGL for 75-10M
Ratzlaff Active whip, 5 Foot Long, ~22 Feet AGL For LF/MW/HF.
Wellbrook ALA1530LN Loop For LF/MW/HF at ~17 Feet AGL
Diamond Discone ~35 feet AGL for Scanner.
QTH: Merced, California, 37, 18, 37N 120, 30, 6W CM97rh

On 22/06/2022 21:18, Philip Atchley via groups.io wrote:

I DO know that I always used a pair of transformers between my Softrock and the external soundcard.

I never use transformers.
With attention to ground loops any disturbance around the centre may be minimised, even eliminated.

73 Alan G4ZFQ

Phil,

I did a little digging and found this:

Re: Audio isolation transformer question
From: Philip Atchley <ko6bb1@...>
Date: Thu, 01 Mar 2018 11:15:15 EST

Hi,

I've used Triad SP-67 600:600 Ohm transformers with great success. Not cheap, but good quality, compact, and they seem to be well matched as images etc are nearly non-existent.

NOTE: I have my HRD set up to display 192KCs of bandwidth, there is a very narrow "notch" right on the LO frequency. That is determined by the low frequency cutoff of the transformer, but it also prevents the sharp "spike" that you may otherwise see at the LO frequency.

Think I got mine from Mouser Electronics.

73 From "The Beaconeer's Lair"

I hope this helps.

73,
Patrick KF4LMZ

Thank you Patrick,

That email sure looks familiar ;-)? Hey, that was over 4 years ago, is it any wonder that this old man forgot it.

<>< 73 From "The Beaconeer's Lair" ><>
Specializing in DXing NDBs (Longwave Beacons)
Phil, KO6BB,

RADIOS:
YAESU: FTDX-101MP Xceiver, Dual SDR Receivers (~2020)
YAESU: FTDX-3000 Xceiver, DSP IF, 300Hz Roofing filter (~2019).
Icom: IC-718 Xceiver, DSP.
Uniden: SDS-200 Scanner, 25-1300MHz (2020)
Portables: Eton Elite 750 (2), AKA Grundig Satelite 750 (2020)
Sangean ATS-909X2 (2021), Tecsun PL-990 (2021)
ACC: MFJ-993B Auto Antenna Matcher.
HOMEBREW 4 Port Antenna Multicoupler, Feeds 4 RX's.
HOMEBREW Tunable LF-MF Pre-Amp.
ANTENNAS: 88 foot Long Ladder-line fed dipole, ~35 feet AGL for MW/HF.
Top Loaded Tee (Dipole fed as single element) ~35 Feet AGL.
Butternut HF-6V 6 Band Vertical, ~12 Feet AGL for 75-10M
Ratzlaff Active whip, 5 Foot Long, ~22 Feet AGL For LF/MW/HF.
Wellbrook ALA1530LN Loop For LF/MW/HF at ~17 Feet AGL
Diamond Discone ~35 feet AGL for Scanner.
QTH: Merced, California, 37, 18, 37N 120, 30, 6W CM97rh

Thank you Alan,

Yes, I remember you mentioning that before.? While I do try to make sure that everything is well grounded to a copper busbar under the operating bench (even the computer tower), there is so much equipment here all interconnected, it's unlikely to achieve a perfect no-ground-loop situation. . .

Since it's been so long since I last did a Softrock install I'll probably have some more questions.

<>< 73 From "The Beaconeer's Lair" ><>
Specializing in DXing NDBs (Longwave Beacons)
Phil, KO6BB,

RADIOS:
YAESU: FTDX-101MP Xceiver, Dual SDR Receivers (~2020)
YAESU: FTDX-3000 Xceiver, DSP IF, 300Hz Roofing filter (~2019).
Icom: IC-718 Xceiver, DSP.
Uniden: SDS-200 Scanner, 25-1300MHz (2020)
Portables: Eton Elite 750 (2), AKA Grundig Satelite 750 (2020)
Sangean ATS-909X2 (2021), Tecsun PL-990 (2021)
ACC: MFJ-993B Auto Antenna Matcher.
HOMEBREW 4 Port Antenna Multicoupler, Feeds 4 RX's.
HOMEBREW Tunable LF-MF Pre-Amp.
ANTENNAS: 88 foot Long Ladder-line fed dipole, ~35 feet AGL for MW/HF.
Top Loaded Tee (Dipole fed as single element) ~35 Feet AGL.
Butternut HF-6V 6 Band Vertical, ~12 Feet AGL for 75-10M
Ratzlaff Active whip, 5 Foot Long, ~22 Feet AGL For LF/MW/HF.
Wellbrook ALA1530LN Loop For LF/MW/HF at ~17 Feet AGL
Diamond Discone ~35 feet AGL for Scanner.
QTH: Merced, California, 37, 18, 37N 120, 30, 6W CM97rh