Author Topic: $45 Ebay Chinese am fm signal generator  (Read 1150 times)

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Offline axantas

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Re: $45 Ebay Chinese am fm signal generator
« Reply #1 on: February 29, 2024, 08:14:37 pm »
What do you want to achive with this "signal generator", which is in fact an AM/FM transmitter.
 

Offline Ned123Topic starter

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Re: $45 Ebay Chinese am fm signal generator
« Reply #2 on: February 29, 2024, 08:21:26 pm »
For alignment of fm receiver . I’m sure other things will be needed.
 

Offline oPossum

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Re: $45 Ebay Chinese am fm signal generator
« Reply #3 on: March 01, 2024, 04:04:52 am »
For a little bit more money you can get something with digital control of frequency and level.

https://www.aliexpress.us/item/3256805634590524.html


For $300 to $500 you can get a nice used HP 8656 or 8657
 


Online factory

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Re: $45 Ebay Chinese am fm signal generator
« Reply #5 on: March 01, 2024, 01:01:19 pm »
The design reminds me of the primitive early AM sig-gens, but missing the output attenuator & internal modulation source and proper RF connectors.

David
« Last Edit: March 01, 2024, 01:07:27 pm by factory »
 

Offline Wallace Gasiewicz

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Re: $45 Ebay Chinese am fm signal generator
« Reply #6 on: March 01, 2024, 01:20:17 pm »
Hello Ned,   
If you are attempting to get started by aligning receivers, may I suggest going to a Hamfest and talking to some of the folks there.   
There are usually used signal generators that you can buy and someone may have some test equipment you may wish to look at.   
If you strike up a conversation, you may find someone with equipment they may be willing to part with for very little money.  .Even if they do not have the equipment for sale at the Hamfest, they may be willing to dig out some stuff for you.  You might even find someone who aligns receivers and has some old equipment  they no longer need.
Starting with aligning receivers is probably a good idea. 
Here is a link to the ARRL Hamfests, just choose your state:   

https://www.arrl.org/hamfests/search 

That little transmitter you are asking about does look like a "Homebrew" item and may work just fine but it does not have a freq readout that you may need. It is pretty "old school".  That is not a bad place to start but there are all sorts of fancy new gadgets.  Look around at test equipment before making up your mind.  You may wish to start with the "basics" or go with "current technology".  The unit you are considering is very much like many old signal generators that have been in use for over 50 years. This includes the IF freq which some old RF generators did have. I think I sold an EICO freq gen for $10, it did work and had the IF freq. It did not go into the FM band though. 
At least the seller of your ebay unit provides instructions on using the unit for tuning radios.   
There does appear to be an audio generator in the unit....quote from ebay description:   
There is a sine wave inside the device with an audio of about 800Hz-1100Hz.
So it does put out a modulated signal.
« Last Edit: March 01, 2024, 01:29:14 pm by Wallace Gasiewicz »
 

Offline Ned123Topic starter

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Re: $45 Ebay Chinese am fm signal generator
« Reply #7 on: March 01, 2024, 09:27:43 pm »
 Thank everyone for your responses.It does include a few things that most basic signal generators don’t, that’s why I was interested in it. I’m just looking for something to do now that I’m retired but can’t justify  spending a lot to check or possibly adjust a few tuners I have.

 


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