My hint is to use low level ( by attenuator or series resistor from Tinysa) to get the correct frequency response,calibrating receiver's IF section most? have agc control.
The filter's output impedance is higher than 50 ohm so a matching resistor or transformer should be used.
You may use tinysa as BFO for ssb also , it's stable and rather clean .
The LO at 443,9 MHz and ERA amplifier are on Ebay and the diode mixer isn't critical.
Sandro
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Re: Step attenuator for QRP transmitter to TinySA
On Sun, Feb 14, 2021 at 08:12 AM, <earla77@...> wrote:
This might have been mentioned, but I just built this $25 step attenuator kit for TinySA experiments- nice quality and works well
?I have one of these kits as well and was using it a few days ago in LOW OUTPUT mode to measure the MDS of a transceiver. What I found was that the attenuation level changed by a random amount just by having a finger on one of the pushbuttons. The way the pushbutton switches "seat" when they are released is irregular, ie the 5dB step may be 5dB...or 3.6dB, etc. I ordered a new step attenuator that uses toggle switches - I'll test it when it arrives. -- John AE5X
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On Mon, Feb 15, 2021 at 05:57 AM, Dave wrote:
The TinySA probably does not have adequate resolution to get to factory spec.
The tinySA has a very stable and accurate TCXO and output? can be between -76dBm and -6dBm The frequency resolution is in the low part of the low output mode (below 45MHz) 156Hz and 312Hz above 45MHz.? ? --
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For more info on the tinySA go to https://tinysa.org/wiki/
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Thank you Dave.
Now we are talking same language.
Qwert.
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Good stuff! ?You are in for a treat!
Start with the 455kHz stage, injecting a signal at the centre frequency just strong enough to detect. ?Align the detector first for best non-distorted signal. Then start aligning the IF filters, decreasing the IF input signal as you get more gain. Once everything is peaked to the Max you may want to de tune ever so slightly to widen the bandwidth. Which coil goes high and which goes low depends upon the arrangement. ?But don¡¯t overdo it.
Then check the 10.245 MHz oscillator and get it right on frequency.
Then proceed to align the 10.7. And the same goes for the first IF too.
I did a receiver with 82MHz first IF, using filters from a cellphone base receiver. Took a while, but it has great performance. Dave
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On Feb 15, 2021, at 09:41, qwert0173@... wrote:
?Hello Dave.
Thank you for the answer.
I am radio engineer who most of the working carrier ( 30+ years ) was close but not quite with the radio related staff. My current project is a way to get back to basics. I am building a lab which will let me measure and tune IF filters.? QRP-Labs is a good resource, I will check.
Thanks again, qwert.
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Hello Dave.
Thank you for the answer.
I am radio engineer who most of the working carrier ( 30+ years ) was close but not quite with the radio related staff. My current project is a way to get back to basics. I am building a lab which will let me measure and tune IF filters.? QRP-Labs is a good resource, I will check.
Thanks again, qwert.
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Is this a radio you have built, or a commercial radio that you think needs tuning? ?Just because you can, does not mean you should. ?The adjustment of a triple conversion superhet is no mere task for the beginner. ?It requires some precision equipment that also requires a skilled operator.
I have repaired many such radios, and while several were easy replacements of failed caps, and one or two were failed semi¡¯s, a surprising number had been fiddled with by their unaware owners and required extensive (and ultimately expensive) alignment of the PLL and IF coils. ?And it was not fun!
If you think you can, and feel the need for the experience, by all means charge ahead. ?But plan to learn a lot, and don¡¯t give up.
The QRP-Labs VFO with TCXO would provide a good oscillator source, and in addition a step attenuator is necessary to get signals weak enough for the task. ?The TinySA probably does not have adequate resolution to get to factory spec. Dave
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On Feb 15, 2021, at 05:38, qwert0173@... wrote:
?Hello John, Sandro.
I would like to tune filters for SW radio. Radio has 3 IF¡®s 455 kHz, 10.7 and 55.8 MHz. BW is 4 till 10 kHz. Which ready modules for tracking generator would supplement TinySA for that task? I learned here that I would need 433 MHz generator, mixer and 350 MHz ( or lower for my application ) low pass filter. What would you suggest?
Br, qwert.
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Hello John, Sandro.
I would like to tune filters for SW radio. Radio has 3 IF¡®s 455 kHz, 10.7 and 55.8 MHz. BW is 4 till 10 kHz. Which ready modules for tracking generator would supplement TinySA for that task? I learned here that I would need 433 MHz generator, mixer and 350 MHz ( or lower for my application ) low pass filter. What would you suggest?
Br, qwert.
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Re: Default parameters when TinySA is switched on
Hello Andrea.
I see different replay from Erik:
"The PRESET/STORE/STORE AS STARTUP is there if you want to start with certain settings."
Br.
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Re: Generator output level
Hi Erik,
Happy to know this is "normal ", and many thanks, if in the future, you can have this corrected.
Best regards ,
Georges F6DFZ?
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Re: Generator output level
George, There is a trick in the HW to extend the output levels down below -44dB. This trick depends on a, not so well specified, parameter of a component. Up till now I have not found, using a limited set of prototypes, deviations larger than 2dB.? Its currently not possible to correct this but?I will look into adding in the config data a manual settable correction entry to compensate for this deviation of lower output levels. --
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For more info on the tinySA go to https://tinysa.org/wiki/
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Hi to the group,
I just received my TinySA from Zeenko, quickly shipped and well tracked by Aliexpress.
This is a great instrument and congratulation to Erik and all for such an outstanding piece of equipment.
Thanks to this group's archives, I could find the ST driver and could upgrade the firmware to the latest version.
I own a HP generator and a Signal Hound SA44 spectrum analyser ; I checked the TinySA from 3 to 144 MHz, and with different signal levels, the result are really impressive.
As a signal generator, from 3 to 144 MHz, output level tracks very finely from -44dBm to -6dBm.
However, there is a sudden discrepancy in the output level from -45dBm to -76dBm, in fact the output level is -4 to -5 dBm lower, independent of frequency.
Is this "normal", and is it possible to correct this ?
Thanks again and best regards.
?
Georges F6DFZ
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On Sun, Feb 14, 2021 at 08:41 AM, Hans Merz wrote:
Do you know a site with a simple explanation to use the TinySA FW upgrade for a Mac??
This is better: https://nt7s.com/2019/11/updating-the-nanovna-firmware/ ?NanoVNA and tinySA use the same update method --
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For more info on the tinySA go to https://tinysa.org/wiki/
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On Sun, Feb 14, 2021 at 08:41 AM, Hans Merz wrote:
Do you know a site with a simple explanation to use the TinySA FW upgrade for a Mac??
Get dfu-util from here:? MacOS seems to be supported This is the update command dfu-util? -a 0 -s 0x08000000:leave -D tinySA.bin It is impossible to brick your tinySA ? --
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For more info on the tinySA go to https://tinysa.org/wiki/
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Hi Erik,
Thanks for your reaction. I will do the test off course. but... I have never done a USB FW upgrade. I have a MAC OS. Do you know a site with a simple explanation to use the TinySA FW upgrade for a Mac?? Sorry for the not-know how¡
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Op 14 feb. 2021, om 16:09 heeft Erik Kaashoek < erik@...> het volgende geschreven:
Hi Hans, Zeenko store will only sell genuine tinySA as it is the store from Hugen. Can you do the attenuator test as described here:? and post a photo of the screen at the end of the test. You may have to upgrade your FW as older FW do not have MEASURE/MORE/LINEAR
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For more info on the tinySA go to
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Hi Hans, Zeenko store will only sell genuine tinySA as it is the store from Hugen. Can you do the attenuator test as described here:? and post a photo of the screen at the end of the test. You may have to upgrade your FW as older FW do not have MEASURE/MORE/LINEAR
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For more info on the tinySA go to https://tinysa.org/wiki/
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First of all my complements to Erik for his TinySA project. I'm really fascinated by it.
(en petje af!)
I have a question and hope that this is the right spot to ask.
After initialising I noticed that in the selftest mentioned that test nr. 11 about the attenuator had failed. (4dBm issue).
I noticed that between manual chosen attenuation steps, it jumps 4 dBm between step 11 and 12 dB.
(firmware _v1.1-52-g1769703). I presume it's not a firmware problem but maybe the attenuator chip?
I bought the SA at the Zeenko store, and I reported them the problem and asked them also what to do best. I hope it's not a clone.
What to do best?
Thanks in advance.?
Hans Merz /Pa3AAW
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Re: Step attenuator for QRP transmitter to TinySA
I have two Kay 475 attenuators. They have a series of toggle switches. You can switch in 0 to 110 dB attenuation in 0.5 dB steps. The ones I have cover 0 to 1.0 GHz. They are high-quality and worth the money. They show up often on eBay.
Zack
I have a Kay Model 520 (Kay #80138) 0 - 10 scale rotary attenuator that I would like to use to allow me to test 100 Milliwatt to 5 Watt QRP transmitters using my TinySA, but I have not been able to find a spec sheet on the attenuator, so I don't know how many watts input it can handle and how much attenuation it will provide.
I, of course, do not want to overload the attenuator and/or the TinySA if I try to test my 5 watt QRP rig.? Anyone have any ideas?
EuGene, KA5NLY
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Re: Step attenuator for QRP transmitter to TinySA
This might have been mentioned, but I just built this $25 step attenuator kit for TinySA experiments- nice quality and works well
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Re: Step attenuator for QRP transmitter to TinySA
You can also use switches and a PCB is not absolutely needed  and the inside  The copper/PCB ground planes combined with the 0805 resistors makes it flat within 1dB up to 500MHz and max practical attenuation is 55dB ( 5+10+20+20)? In the shown attenuator there is one additional 20dB stage totalling 75dB but that is too much in this construction. --
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For more info on the tinySA go to https://tinysa.org/wiki/
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