Date   

Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Klaus Brosche
 

If that happens again in the future:

1st: check the DUOr reception in stand-alone mode first,
w/o a PC connection/connected, just receiving with the DUOr alone.

If that's OK, and receive is not OK within SW-2 software, I would guess
it's a driver (USB), OS or some other Software issue.

Klaus, DK3QN


Am 21.10.2020 um 20:09 schrieb Bertrand via groups.io:

Hello all

I made a 3rd reset of the rx, and it works now ....
computer mysteries added to radio mysteries?

Thanks to all



Le 21/10/2020 à 19:57, Bertrand via groups.io a écrit :
I have tried all same cable and antenna with an other RX
and other antenna and cable with FDM-DUO



Le 21/10/2020 à 19:52, Klaus Brosche a écrit :
"plugging in any antenna has absolutely no effect visually or to the ear."

Did you plug in the various antennas directly into the DUOr or via a Coax switch?

Did you check the Coax cable(s) for a short? "Standard" PL-259 male connectors
are somewhat prone to that.

Klaus, DK3QN


Am 21.10.2020 um 12:29 schrieb Bertrand via groups.io:
Hello all

I am the very new owner of an FDM-DUOr, I was able to play with it yesterday all day without problems.
But this morning it acts as if there is no antenna, I only have noise on all bands and plugging in any antenna has absolutely no effect visually or to the ear.
Do you have any idea what's going on?
(I performed a reset, but no effect)

73 and stay Safe






Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Bertrand
 

Hello all

I made a 3rd reset of the rx, and it works now ....
computer mysteries added to radio mysteries?

Thanks to all



Le 21/10/2020 à 19:57, Bertrand via groups.io a écrit :
I have tried all same cable and antenna with an other RX
and other antenna and cable with FDM-DUO



Le 21/10/2020 à 19:52, Klaus Brosche a écrit :
"plugging in any antenna has absolutely no effect visually or to the ear."

Did you plug in the various antennas directly into the DUOr or via a Coax switch?

Did you check the Coax cable(s) for a short? "Standard" PL-259 male connectors
are somewhat prone to that.

Klaus, DK3QN


Am 21.10.2020 um 12:29 schrieb Bertrand via groups.io:
Hello all

I am the very new owner of an FDM-DUOr, I was able to play with it yesterday all day without problems.
But this morning it acts as if there is no antenna, I only have noise on all bands and plugging in any antenna has absolutely no effect visually or to the ear.
Do you have any idea what's going on?
(I performed a reset, but no effect)

73 and stay Safe





Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Klaus Brosche
 

Just to make sure:

same cableing into another receiver: reception OK.

same cableing to the DUOr: reception NOT OK.

Correct?

Klaus, DK3QN


Am 21.10.2020 um 19:57 schrieb Bertrand via groups.io:

I have tried all same cable and antenna with an other RX
and other antenna and cable with FDM-DUO



Le 21/10/2020 à 19:52, Klaus Brosche a écrit :
"plugging in any antenna has absolutely no effect visually or to the ear."

Did you plug in the various antennas directly into the DUOr or via a Coax switch?

Did you check the Coax cable(s) for a short? "Standard" PL-259 male connectors
are somewhat prone to that.

Klaus, DK3QN


Am 21.10.2020 um 12:29 schrieb Bertrand via groups.io:
Hello all

I am the very new owner of an FDM-DUOr, I was able to play with it yesterday all day without problems.
But this morning it acts as if there is no antenna, I only have noise on all bands and plugging in any antenna has absolutely no effect visually or to the ear.
Do you have any idea what's going on?
(I performed a reset, but no effect)

73 and stay Safe





Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Bertrand
 

I have tried all same cable and antenna with an other RX
and other antenna and cable with FDM-DUO



Le 21/10/2020 à 19:52, Klaus Brosche a écrit :

"plugging in any antenna has absolutely no effect visually or to the ear."

Did you plug in the various antennas directly into the DUOr or via a Coax switch?

Did you check the Coax cable(s) for a short? "Standard" PL-259 male connectors
are somewhat prone to that.

Klaus, DK3QN


Am 21.10.2020 um 12:29 schrieb Bertrand via groups.io:
Hello all

I am the very new owner of an FDM-DUOr, I was able to play with it yesterday all day without problems.
But this morning it acts as if there is no antenna, I only have noise on all bands and plugging in any antenna has absolutely no effect visually or to the ear.
Do you have any idea what's going on?
(I performed a reset, but no effect)

73 and stay Safe




Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Klaus Brosche
 

"plugging in any antenna has absolutely no effect visually or to the ear."

Did you plug in the various antennas directly into the DUOr or via a Coax switch?

Did you check the Coax cable(s) for a short? "Standard" PL-259 male connectors
are somewhat prone to that.

Klaus, DK3QN


Am 21.10.2020 um 12:29 schrieb Bertrand via groups.io:

Hello all

I am the very new owner of an FDM-DUOr, I was able to play with it yesterday all day without problems.
But this morning it acts as if there is no antenna, I only have noise on all bands and plugging in any antenna has absolutely no effect visually or to the ear.
Do you have any idea what's going on?
(I performed a reset, but no effect)

73 and stay Safe



Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Bertrand
 

Here is one

for the tests : RTL Broadcast 234khz


Le 21/10/2020 à 18:47, Simon a écrit :
Put up a screen shot if using pc..this will help..







Re: #fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Simon
 

Put up a screen shot if using pc..this will help..


#fdm-duor FDM-DUOr act like there is no antenna #fdm-duor

Bertrand
 

Hello all

I am the very new owner of an FDM-DUOr, I was able to play with it yesterday all day without problems.
But this morning it acts as if there is no antenna, I only have noise on all bands and plugging in any antenna has absolutely no effect visually or to the ear.
Do you have any idea what's going on?
(I performed a reset, but no effect)

73 and stay Safe


Re: SW2 v3.45

Vianney Colombat
 

Hello Raimund,

no, latest change on TCP connection was on version 1.149

Vianney


Il 18/10/2020 14:31, Raimund ha scritto:
Hi Vianney,

I have a question related to Software FDM S2, S3.

Does the latest version include any changes regarding the TCP connection?

Until now I have never read a comment with specifics.

Thanks,
Raimund
.

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Re: Elad Duo Overload Performance Measurements

Klaus Brosche
 

Hi Clint,

Thanks for your comments, appreciated!

From my remembrance, QST had reviews on the TR-7 as well as on SWAN/Cubic radios, e.g. Astro-150 and Astro-102 (at least).

For their testing process and possible 'bad' result(s) for a specific DUT, they seem to get back to the manufacturer
first order to discuss such findings *before* they publish their review in QST finally. (E.g. for SunSDR)

Which I find is a fair procedure.

As far as advertising dollar revenue goes: sure they are in a need to leverage from this money.
On the other hand, manufacturers need those ads in order to promote their product(s).
QST is one of their most (if not *the* most) important marketing media, imho not only for the US and Canada.

Re. test results (numbers, graphs, etc.) vs. textual wording in QST reviews, being not always in synch:
This, imho, stems from the fact that the textual reviewer, the one that is putting the DUT through an
on-the-air experience, is not the same person who performed the technical analysis generating the numbers.

I would assume (and expect) that the technical analysis happens *before* the on-the-air review (reason: see
above) and that the latter reviewer is not given the 'numbers' beforehand.

Thus, there is a likelihood for discrepancies between 'numbers' and 'on-the-air experience'.
From my understanding, the 'on-the-air' review process is done at the (textual) reviewers
private location (including his antennas, etc.) which, depending on the local circumstances, may or
may not disclose any particular deficiencies of a product.
Not to speak about external influencing factors for such kind of 'on-the-air' tests, like RF propagation/
Solar Cycle, neighbourhood of many high power ham radio stations, etc.

Overall, I must say I have full trust in QST reviews, especially in the 'numbers' part ;-)
My only 'gripe' is their inconsistency in a few cases where they've changed the vertical scale on
some of their graphs, which is a little misleading when looking at these with just a quick glance.

73, and stay safe!

Klaus, DK3QN


Am 18.10.2020 um 00:39 schrieb Clint Chron:

Hi Klaus,

 

The author of the article was Rob.  I have a 2020 email from Rob with the same Elad Duo report.  I was comparing notes with Rob on a couple of questionable performance areas – I had much better test results of my Duo.  Rob acknowledged that perhaps he had a defective Duo and would test again if he could get hold of a more recent unit.

 

I like the QST product reviews – lots of good measured technical specs, but I cannot totally depend upon those reviews to give the complete picture on the performance of a radio.  Sometimes, the written review does not totally match with the measured specs.  A typical example would be some of the noisy transmitters that have been reviewed.  The specs plainly show the noise trash, but no mention is made of this noise trash in the write-up.  A much older example is the SGC SG-2020 transceiver.  The ones with the ADSP-II module always sounded terrible on SSB.  I owned four of them at different times – I wanted to make sure that I did not have a bad unit.  I went back and reviewed the QST product review.  No mention was made of the terrible sounding audio, but the measured receiver audio response identified the problem.  Today, when someone asks me about the SG-2020, I tell them it is a great radio but the audio on SSB sounds terrible and the alignment procedure is impossible unless you get the customized cal settings from SGC.

 

ARRL is in a difficult position.  The organization exists because of advertising dollar revenue.  If they upset the big manufacturers by writing critical reviews, then ARRL will soon be out of business.  Some radio manufacturers never submitted their radios to QST for testing.  Typical examples would be the Atlas 210 series and the Swan series.  I can only guess that the QST testing process would turn up a number of serious issues.  Conversely, I never saw any reviews for the Collin’s S line and the Drake TR series of transceiver.   I think that it also should be noted that much of the current Product Review receiver testing process is a direct result of push-back from Rob and Adam Farson.  It took them several years to convince the product testers to update their testing process to more accurately depict actual receiver performance.

 

So to balance the info in QST product reviews, I also have to read the write-up from Rob and Adam Farson.  For Rob’s receiver result test site, one can easily rank the radios on other factors.  I feel confident that his current ranking is accurate and Rob will tell you that any of the top ten radios would work good for just about anyone.

 

The Elad Duo is in a unique niche market – it does things that no other radio will do.  I have an IC-7300 and I like the radio.  Its overload performance is slightly better than the Elad Duo.  I keep going back to the Elad Duo because of the finely detailed spectrum display with the SW2 software, the small size, the 0 dbm output signal generator, and the product support.    

 

73

Clint

W7KEC

 

 

 

 

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Klaus Brosche
Sent: Saturday, October 17, 2020 2:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] Elad Duo Overload Performance Measurements

 

Hi Clint,

 

It was ME!

 

In Sherwoods 'official' list, which he calls 'Receiver Test Data', there is no entry about the DUO.
Thats for sure, I've just checked that list again just a minute ago.

 

The data published re. the link you've provided are from 2015, as far as the date code is concerned,
and it is totally unclear to me who the author of this writing was!

 

This writing is not signed by Sherwood nor does any DUO performance entries show up at
Sherwoods list!

 

For any performance ratings of the DUO, I'd rather rely on the QST reviews dated May 2016.

 

IMHO, QST reviews have a coherent testing methodology which is also published and explained.

 

However, sometimes you need to read 'between the lines' or definitely read their 'sidebars' ;-)

 

Klaus, DK3QN

 

 

Am 17.10.2020 um 16:46 schrieb Clint Chron:

Someone mentioned that there was not any receiver test reports for the Elad Duo on Rob Sherwood's site.  Rob provided test results in this link:
https://www.dj0ip.de/sherwood-forest/sherwood-hf-xcvr-tests/elad-ftm-duo/

The Elad S2 receiver has the same basic receiver as the Duo.  In this link, Adam Farson provides test results for the S2:

https://www.ab4oj.com/sdr/elad/fdm_s2_notes.pdf

The overload capability of the Elad Duo compares very favorably with other high end SDR radios.  If you add a receiver band pass filter, the overload results are among the best of the class.

Please note that the high end analog transceivers still have better overload performance than most SDR receivers.

73
Clint
W7KEC

 



Re: Duo with pc headset ssb #eladduo

Harke Smits
 

Hello Paul,

I would start with reading the note by Andy first. You can find it here:

Indeed, I use the DUO with a DB6NT transverter (3cm), or my own (13cm), but the switching principle is exactly the same. So you need to place a resistor (4k7) from +TX (at 2m) to output. I use a 3 resonator hi-Q band pass filter at 144 MHz with a notch at 122 MHz.Align with vna. At the input a low pass filter. Also the TX section uses a low pass filter. In fact rather simple. Let me know by pm if you need more info. The sequencer is in the transverter.
Best 73 de

Harke, PA0HRK


On Sunday, October 18, 2020, 04:33:45 PM GMT+2, Paul Andrews <pandrews@...> wrote:


Harke,

Thanks for the good news.  I want to use the Duo as an IF radio for a Khune transverter.

Do you also use a filter on the TX output?

Should I use a bandpass filter centered at 144 MHz or a 122 MHz bandstop (notch) or both?

I enjoyed your webpage on SpectraVue.

73 - Paul - W2HRO

On Sun, Oct 18, 2020, 06:41 Harke Smits via groups.io <yrrah53=yahoo.com@groups.io> wrote:
Gentlemen,

Allow me to throw some experience in. A couple of years ago I was looking for a decent 2m sdr and I was unimpressed by the market. Either not good enough or too expensive. My application is base station for microwave EME. Then I was informed of the article by G4JNT about using the FDM-DUO at 2 m and I immediately bought a DUO (second hand). It uses the DUO RX in undersampling mode, it's clock is at about 122 MHz. The TX is used normally as the sample frequency is higher than 144 MHz at about 225 MHz. All you need are some filters and amplifiers. It works like a charm and I could even recommend using the DUO as your 2m home base station in all but the most demanding operating conditions. I used a vna to align the filters; with a notch at about 122 MHz. I do not need a low noise figure at 2m obviously, but that is not a problem at all actually with a PGA103 in the front end. With a good signal generator I calibrated the DUO's S-meter by inserting a small attenuator at the RX side in front of the DUO. I found the compression level at 2m to be quite high but unfortunately I can not do NPR measurements at 144 MHz due to lack of a good notch filter.  I have used it at 13 and 3 cm EME without any limitation. I hear beacons, sun- and moon-noise and of course: many stations. For me this has made EME (with my relative small station) really great fun.
I have never operated the DUO in any other operating condition, but at 2 m it's great.
The filters and amplifiers are housed in a small case under the DUO which also contains a Wenzel 10 MHz OCXO to stabilize the DUO.
Just a happy user and no connection to ELAD in any form......
Best 73 de

Harke, PA0HRK


On Sunday, October 18, 2020, 03:31:40 AM GMT+2, Paul Andrews <pandrews@...> wrote:


Are you using this 144 Mhz filter / amp design with your Duo?

The Duo as a 28 MHz IF radio is excellent.  I use it on 432 and 1296 MHz.

No I better understand the limitations at 144 MHz undersampling.

If the Duo is run at 144 MHz with a transverter, is the filtering still required?

73 - Paul - W2HRO

On Sat, Oct 17, 2020, 18:34 Neil Smith G4DBN <neil@...> wrote:
Hi Paul I use a G4DDK Anglian transverter to get the DUO on to 144, but
it is quite simple to get around the mathematical and technological
issues with the DUO at 144 MHz.  Running 144 MHz on a 122.88 MHz sampled
A/D converter means you lose a lot of sensitivity simply because of the
way sampling works. The noise figure of the DUO at 144 MHz is extremely
poor as a result.  Also there is aliasing, so you get noise from the
image frequency as well, and Band 2 FM broadcast breakthrough from
around 100 MHz.

Andy G4JNT has designed a filter and amplifier board to improve the DUO
performance on 144. Have a look at
http://www.g4jnt.com/FDM-DUO_at_VHF.pdf
<http://www.g4jnt.com/FDM-DUO_at_VHF.pdf> where all is explained...

Neil G4DBN

On 17/10/2020 23:19, Paul Andrews wrote:
> Neil,
>
> Do you use a 144 MHz IF with your 10 GHz system.   I tried using my
> FDM-DUO configured for 144 MHz with a Khune transverter.  I was not
> successful looking for the beacon.
>
> 73 - Paul - W2HRO







Re: Duo with pc headset ssb #eladduo

Paul Andrews
 

Harke,

Thanks for the good news.  I want to use the Duo as an IF radio for a Khune transverter.

Do you also use a filter on the TX output?

Should I use a bandpass filter centered at 144 MHz or a 122 MHz bandstop (notch) or both?

I enjoyed your webpage on SpectraVue.

73 - Paul - W2HRO

On Sun, Oct 18, 2020, 06:41 Harke Smits via groups.io <yrrah53=yahoo.com@groups.io> wrote:
Gentlemen,

Allow me to throw some experience in. A couple of years ago I was looking for a decent 2m sdr and I was unimpressed by the market. Either not good enough or too expensive. My application is base station for microwave EME. Then I was informed of the article by G4JNT about using the FDM-DUO at 2 m and I immediately bought a DUO (second hand). It uses the DUO RX in undersampling mode, it's clock is at about 122 MHz. The TX is used normally as the sample frequency is higher than 144 MHz at about 225 MHz. All you need are some filters and amplifiers. It works like a charm and I could even recommend using the DUO as your 2m home base station in all but the most demanding operating conditions. I used a vna to align the filters; with a notch at about 122 MHz. I do not need a low noise figure at 2m obviously, but that is not a problem at all actually with a PGA103 in the front end. With a good signal generator I calibrated the DUO's S-meter by inserting a small attenuator at the RX side in front of the DUO. I found the compression level at 2m to be quite high but unfortunately I can not do NPR measurements at 144 MHz due to lack of a good notch filter.  I have used it at 13 and 3 cm EME without any limitation. I hear beacons, sun- and moon-noise and of course: many stations. For me this has made EME (with my relative small station) really great fun.
I have never operated the DUO in any other operating condition, but at 2 m it's great.
The filters and amplifiers are housed in a small case under the DUO which also contains a Wenzel 10 MHz OCXO to stabilize the DUO.
Just a happy user and no connection to ELAD in any form......
Best 73 de

Harke, PA0HRK


On Sunday, October 18, 2020, 03:31:40 AM GMT+2, Paul Andrews <pandrews@...> wrote:


Are you using this 144 Mhz filter / amp design with your Duo?

The Duo as a 28 MHz IF radio is excellent.  I use it on 432 and 1296 MHz.

No I better understand the limitations at 144 MHz undersampling.

If the Duo is run at 144 MHz with a transverter, is the filtering still required?

73 - Paul - W2HRO

On Sat, Oct 17, 2020, 18:34 Neil Smith G4DBN <neil@...> wrote:
Hi Paul I use a G4DDK Anglian transverter to get the DUO on to 144, but
it is quite simple to get around the mathematical and technological
issues with the DUO at 144 MHz.  Running 144 MHz on a 122.88 MHz sampled
A/D converter means you lose a lot of sensitivity simply because of the
way sampling works. The noise figure of the DUO at 144 MHz is extremely
poor as a result.  Also there is aliasing, so you get noise from the
image frequency as well, and Band 2 FM broadcast breakthrough from
around 100 MHz.

Andy G4JNT has designed a filter and amplifier board to improve the DUO
performance on 144. Have a look at
http://www.g4jnt.com/FDM-DUO_at_VHF.pdf
<http://www.g4jnt.com/FDM-DUO_at_VHF.pdf> where all is explained...

Neil G4DBN

On 17/10/2020 23:19, Paul Andrews wrote:
> Neil,
>
> Do you use a 144 MHz IF with your 10 GHz system.   I tried using my
> FDM-DUO configured for 144 MHz with a Khune transverter.  I was not
> successful looking for the beacon.
>
> 73 - Paul - W2HRO







Re: Hangup on TX

Antony Watts
 

To conclude on this puzzle. The inputs I got were

Morris
- 3t ferrites on USB leads. Ordered FT140-43 x 4

Neil
- TEST PTT
- PTT foot switch,
- quit WSJT,
- RF spikes

Vianney
- if DTR or RTS used disconnect CAT cable.
- Change VFO A/B or VFO mode (USB, LSB, CW…)

My solution has been to try USB cable with 3turns though FT140-43 toroids, which worked, and now I have swapped to two screened USB cables with built in ferrites at both ends. And the problems have gone away.

Thanks to everyone

Antony
M0IFA


Re: Elad Duo Overload Performance Measurements

Clint Chron
 

I am not sure when QST shifted from having manufacturers submit radios for testing to the current plan of buying the radios outright.  To QST's credit, 50 years ago, they would not accept any advertisements for beam antennas that listed antenna gain.

One interesting stat about the equipment buying habits of hams.  Quantity of sales does not always equate to quality of the equipment. Atlas supposedly sold about 40,000 units during the period of 1974 to 1979, but the 210X radios had some serious problems - noisy transmitters and drifty VFOs.  Yet the radio was popular for mobile setups because it did what no other radio could do.  The quality and features of the Japanese manufacturers finally put Atlas out of business.  Today, there are some radios that have excellent quality and low price, but not many units are sold - I suspect that the Elad Duo is in that category.  I read somewhere that Elecraft has sold less than 8000 K3s over the last 8+ years.

Icom has sold 20,000+ IC-7300s in the last 5 years - high quality radio, low price, and excellent features.  It would interesting to see sales stats for radios from other manufacturers.

73
Clint
W7KEC


Re: SW2 v3.45

 

Hi Vianney,

I have a question related to Software FDM S2, S3.

Does the latest version include any changes regarding the TCP connection?

Until now I have never read a comment with specifics.

Thanks,
Raimund
.


Re: Tx / Soundcard levels

DAVID IW5BNL
 

Hi All,

I definitely found time to work on IQ modulator on DUO.
I confirm Andy data : with IQ mode enable all A/D scale can be used.
I implement a SSB on gnu radio based on QEX Nov/Dec 2014 article : 'Controlled Envelope Single Sideband' by W9GR.
It work very well producing very clean DUO spectrum even at high compression level.
DUO internal IQ modulator is very well designed.
Attached a screen shot of my IQ ssb modulator.
If some one like to test it I can share.

Ciao,

David
IW5BNL

Il giorno sab 19 set 2020 alle ore 13:44 Andy G4JNT <andy.g4jnt@...> ha scritto:
I'm posting this to both Groups as it's an odd interrelation between WSJT-X and the Elad FDM-Duo .
I was testing the Duo's internal soundcard on Tx, monitoring the level generated at the 0dBm output.

As a source I was Using I2PHD's T-Cube tone generator, and also a utility I wrote to play .WAV files.  I write these .WAV files directly from software so know exactly what range of digits make up any waveform.  I've generated several ones with a single tone at 1kHz at levels of 0dB (32767/-32676 peak-peak)  -3db (27170 pk-pk) , -6, -9dB   etc etc.   These were used to verify that T-Cube gave an output level, when set to 0dB of +/- 32767, set to -20dB, +/- 3277   etc etc.    Everything is in agreement, and proved that T-Cube's output level can be determined exactly

The FDM-Duo appears to saturate, with it's 0dBm at maximum output, at a soundcard input level of around -7.7dB,  ie digital values up to +/- 13500.

I also tested a PCM2900 line in/out USB sondcard chip, and this follows faithfully (with 2V pk-pk of audio out) at a level of 0dB input from the driving software.

Now the oddity :

The WSJT-X tune control nicely drives the FDM-Duo and moving the 'Pwr' slider reduces Tx level almost as soon as it is moved.   This suggests it is delivering a tone of +/- 13500 or thereabouts.  If it were any higher, there'd be a delay in dropping the 'Pwr' control before RF power actually dropped.  ie. it would still be delivering max power at half slider setting.   This sort-of matching power level for WSJT-X vs. FDM-Duo was also observed by G4DBN when this subject cropped up a few weeks ago - and was speculated, at the time, as perhaps some sort of 'standard'
........BUT .............
When I do the same test using the PCM2900 soundcard chip, TUNE on WSJT-X delivers an output from it corresponding to +/-32767 digital drive, and the 'Pwr' control lowers it from, this.  Which intuitively, I would have expected to be the case.    Why should WSJT-X NOT give maximum amplitude from teh soundcard?

It's almost as if WSJT-X is recognising what sort of Soundcard is connected, and adjusting the digital drive level, (the numbers sent to the soundcard device) accordingly.  I find this very hard to believe !



Re: EU/worldwide S3 Owners

Morris G1PIB
 

Hello Paul,
I do not know of any UK deliveries yet !
Mine is still on order I can only put in down to virus causing
short staffed customs ?
jugding from what I hear it  is still worth the wait...
As a point of discussion I wonder if the S3  will be incorporated
into the Duo X  (with downconvertor as an added bonus )
that would something else !!

Morris g1pib  .....returned to overcast Somerset


Re: Duo with pc headset ssb #eladduo

Harke Smits
 

Gentlemen,

Allow me to throw some experience in. A couple of years ago I was looking for a decent 2m sdr and I was unimpressed by the market. Either not good enough or too expensive. My application is base station for microwave EME. Then I was informed of the article by G4JNT about using the FDM-DUO at 2 m and I immediately bought a DUO (second hand). It uses the DUO RX in undersampling mode, it's clock is at about 122 MHz. The TX is used normally as the sample frequency is higher than 144 MHz at about 225 MHz. All you need are some filters and amplifiers. It works like a charm and I could even recommend using the DUO as your 2m home base station in all but the most demanding operating conditions. I used a vna to align the filters; with a notch at about 122 MHz. I do not need a low noise figure at 2m obviously, but that is not a problem at all actually with a PGA103 in the front end. With a good signal generator I calibrated the DUO's S-meter by inserting a small attenuator at the RX side in front of the DUO. I found the compression level at 2m to be quite high but unfortunately I can not do NPR measurements at 144 MHz due to lack of a good notch filter.  I have used it at 13 and 3 cm EME without any limitation. I hear beacons, sun- and moon-noise and of course: many stations. For me this has made EME (with my relative small station) really great fun.
I have never operated the DUO in any other operating condition, but at 2 m it's great.
The filters and amplifiers are housed in a small case under the DUO which also contains a Wenzel 10 MHz OCXO to stabilize the DUO.
Just a happy user and no connection to ELAD in any form......
Best 73 de

Harke, PA0HRK


On Sunday, October 18, 2020, 03:31:40 AM GMT+2, Paul Andrews <pandrews@...> wrote:


Are you using this 144 Mhz filter / amp design with your Duo?

The Duo as a 28 MHz IF radio is excellent.  I use it on 432 and 1296 MHz.

No I better understand the limitations at 144 MHz undersampling.

If the Duo is run at 144 MHz with a transverter, is the filtering still required?

73 - Paul - W2HRO

On Sat, Oct 17, 2020, 18:34 Neil Smith G4DBN <neil@...> wrote:
Hi Paul I use a G4DDK Anglian transverter to get the DUO on to 144, but
it is quite simple to get around the mathematical and technological
issues with the DUO at 144 MHz.  Running 144 MHz on a 122.88 MHz sampled
A/D converter means you lose a lot of sensitivity simply because of the
way sampling works. The noise figure of the DUO at 144 MHz is extremely
poor as a result.  Also there is aliasing, so you get noise from the
image frequency as well, and Band 2 FM broadcast breakthrough from
around 100 MHz.

Andy G4JNT has designed a filter and amplifier board to improve the DUO
performance on 144. Have a look at
http://www.g4jnt.com/FDM-DUO_at_VHF.pdf
<http://www.g4jnt.com/FDM-DUO_at_VHF.pdf> where all is explained...

Neil G4DBN

On 17/10/2020 23:19, Paul Andrews wrote:
> Neil,
>
> Do you use a 144 MHz IF with your 10 GHz system.   I tried using my
> FDM-DUO configured for 144 MHz with a Khune transverter.  I was not
> successful looking for the beacon.
>
> 73 - Paul - W2HRO







Re: Elad Duo Overload Performance Measurements

Jerry
 

On Sat, Oct 17, 2020 at 03:39 PM, Clint Chron wrote:
ARRL is in a difficult position.  The organization exists because of advertising dollar revenue.  If they upset the big manufacturers by writing critical reviews, then ARRL will soon be out of business.  Some radio manufacturers never submitted their radios to QST for testing. 
I don’t know how the ARRL did reviews back in the days when Swan, Collins, and Drake made amateur gear, but nowadays manufacturers don’t “submit their radios to QST for testing”. When QST does a rig review, they buy the rig anonymously through retail channels. This ensures they get a rig representative of production and not one cherry-picked by the manufacturer. After testing the rig, they sell it at auction.


Re: New Duo X

Marc Pilotte
 

The FDM-DUO is just fine w/it’s SO-239 connectors. I...and hundreds upon hundreds of other PROUD owners of the FDM-DUO’s, would be greatly inconvenienced by that mod. 
If it ain’t broke...YOU CAN’T FIX  IT!!!
de WB9DBD 

On Sat, Oct 17, 2020 at 2:53 PM PAUL-M7PVS <psloper@...> wrote:
Ahh ok :) well it’s a shame there is no native Mac app for this as a Mac user as well as windows and Linux but I think flex have got it wrong by having a. Free app for windows and a pay for app for the flex but as we all know software developers cost lots of money


From: EladSDR@groups.io <EladSDR@groups.io> on behalf of Mike Chace-Ortiz <mchaceortiz@...>
Sent: Saturday, October 17, 2020 3:28:59 PM

To: EladSDR@groups.io <EladSDR@groups.io>
Subject: Re: [EladSDR] New Duo X
 
It was Paul, 

I was addressing the other Paul (Elad USA) about my experience with the SunSDR. macOS native software but RX lacking compared to FDM-S2.

73
—mco

On Oct 17, 2020, at 10:22, PAUL-M7PVS <psloper@...> wrote:

I thought it was something to do with apple ;)


From: EladSDR@groups.io <EladSDR@groups.io> on behalf of Klaus Brosche <klaus.brosche@...>
Sent: Saturday, October 17, 2020 3:19:31 PM
To: EladSDR@groups.io <EladSDR@groups.io>
Subject: Re: [EladSDR] New Duo X
 
Besides the international standard of 'Q code' abbreviations, there are quite
a number of ham radio specific abbreviations used in CW traffic.
That is to speed up the communication flow.

The word "sorry" in morse code would be sent like this:
...  ---  .-.  .-.  -.--  (5 letters)

"sri" looks like this:
...  .-.  ..   (3 letters)

A list of these specific ham radio abbreviations can be found here:
https://cwops.org/wp-content/uploads/2018/07/CW-Abbreviations.pdf

72, Klaus, DK3QN


Am 17.10.2020 um 15:32 schrieb Paul White:
"sri"?
What am I missing?



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