#951

Episode 951
Let's take a look at how to test the receiver section of the radio using the RF output function of the TinySA. I try 144.000 MHz then 10.7 MHz both with narrow band FM modulation at 1000 Hz.
Be a Patron: / imsaiguy

[@w2aew]

You can generate a simple unmodulated carrier that is inside the SSB audio bandwidth and simply listen to the tone. For example, set the radio to 144MHz, and set your generator to 144.001MHz and you should hear a 1kHz tone if you set the radio to USB.

[@__--JY-Moe--__]

I saw a video about a guy that sent a photo.jpg like that!! it was funny cool !! but since there is no logic testing in this, it's kind of boring. 2 me!! good luck!!

[@joseppuig925]

I have used the TinySA to troubleshoot vintage AM-FM radios as well, injecting signal at the IF frequency, and at RF to peak sensitivity, and the spectrum analyzer to locate the local oscillator to see if it works and track its frequency as I adjust it to range. BTW, an FM demodulator will let AM signal to be listened, but under certain conditions: that the input signal has to be below the limiting threshold of the IF amplifier, because when the signal is high, it gets limited and amplitude variation is eliminated (thus, AM modulated information) by at least 40 or more dB (and this is called AM rejection ratio for an FM demodulator)

[@felixcat4346]

Thanks for the post ☺️.

[@Soupie62]

LOVE that little pick you use to activate the screen on the Tiny SA. Where did you get it?

[@IMSAIGuy]

I came with the unit. but any guitar pick would work

[@Bouvier_des_Flemish]

よくこんな古い無線機を持っていますね。私が大学生の時、無線クラブにありました。真夏になるとPLLロックが外れていました。懐かしいですが、物持ちの良さに驚きます。これでは失恋の苦い体験も忘れることがないのではないでしょうか？

[@peterrizzi7630]

I have the same radio with the same problem I would love to get one of your replacement bords

[@helijim]

I'm wondering whether to get a TinySA for aligning and repairing a CB or something like a 0.5MHz-470MHz RF Signal Generator Meter Tester for FM Radio Walkie-talkie. I think these can also do FM deviation. Do you have any thoughts? Thanks.

[@IMSAIGuy]

I have a playlist for the tinySA. you can see me use it in many ways.

[@PapasDino]

I think the FM discriminator output you described at the end of the block diagram is going to be "Audio Output" not the mode "Amplitude Modulation (AM)". Just call me nit-picky! ;-)

[@elinbenson]

Early Icom radios have problems with the trimer capacitors in their VCOs.

[@pyrokinetikrlz]

interesting to know why the radio working in FM mode was able to pick up AM signal (though, with low gain)

[@musicstevecom]

Great Video almost what I want to do, Can the TinySA RF Generator or Ultra do this I want to do the complete AM and FM ailment for a High End Tuner or receiver from the late 70's for Pioneer SX-950 and all the SX-xx50 which is very detailed?

[@IMSAIGuy]

the TinySA would be better than nothing.

[@DAVIDGREGORYKERR]

So is that transceiver is the last discrete component transceiver before ICOM moved to SDR based transceivers.

[@IMSAIGuy]

no, many many more after that one

[@milesclouston2005]

I have an ICOM IC-245 with us supposedly dead PLL. Could it be saved by this method?

[@IMSAIGuy]

I was not able to complete this project

[@milesclouston2005]

@@IMSAIGuy I am truly sorry to hear that! :(

[@cnvogel]

For SSB, just send a unmodulated carrier 1kHz higher or lower than your IF, should demodulate as 1kHz audio.

[@R2AUK]

Many thanks for sharing. Would be especially interesting to learn how the FM modulator/demodulator and PLL are implemented in this unit. BTW, SSB-modulated signal is pretty simple to generate since it's a just a tone (CW) shifted -N hertz for LSB and +N hertz for USB.

[@__--JY-Moe--__]

👍

[@TheRetiredtech]

Test it with cw I. Ssb .

[@jdmccorful]

Good stuff, looking forward to the troubleshooting.Thanks.