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Another Signal generator question

2FB327

2FB327

Active Member
Oct 31, 2012
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Are there any other affordable option besides the
B&K 2040 or the 1040 service master?

All I want to do is inject the tone into the radio to set receive and maybe have a 1Khz tone.

I can't see paying a couple of hundred dollars for something that might work from eba*.

Is there a model that does the above?
 

If you are just wanting a 1khz tone, use an af generator like audacity. I made a cable with an 1/8" mono plug, a dpdt switch and a mic plug.

But for the rx section you'll need an rf generator and some of those won't do af.
 
the cheapest way to do it would be to use another CB radio connected to a dummy load as your signal generator.
this will be a much more stable signal than any of the cheap RF signal gens available on ebay.
turn the power down to about 1 watt so you can leave it keyed for extended periods, and if it provides too strong a signal you can just move it into another room.
(dont use any signal more than about an S-1 to align your radio)

and for the 1khz tone, just get a kit like this:
Canakits CK107 1kHz Portable Sine Wave Generator Kit | eBay

you inject it into the mic socket of the radio you are using for the sign gen and you will have a modulated tone to tune with.

you can also use that kit to allow you to tune the transmitter for max PEP watts.
LC
 
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Thanks so much, I'll get the kit.

I got a lot of old radios to use so I'm good there.
 
I suppose you can use another radio to align the receive of another. But let's look at this for another moment. First, how are you going to adjust the receiver's sensitivity? When an alignment is done, you have to use a very low signal at a specific given strength so as to not overpower the AGC circuit in the receive.

One microvolt feed is pretty much the universal method/level given to do this operation. One microvolt - or written as 1uV - is one millionth of just one watt is then inputted into the radio's SO-239 plug. Even if you turn your 'generator radio' output down all of the way using a dummy load instead of an antenna, the proximity to the radio being aligned will easily have more than 4uV getting in to its receive. Which will cause the AGC circuit to kick in and this will affect the radio sensitivity and the subsequent result will be skewed. The game is over once that level is exceeded and the AGC kicks in.

Example of a Galaxy radio input requirement - which is typical BTW:

AM/FM RF & IF SENSITIVITY:
RF Generator output to 26.965 MHz at 1uV modulated 30% with 1 KHz audio tone.
Click to expand...

When it is time to adjust the radio's receive meter to S-9; then 100uV is used. This requires a calibrated output from the sig/gen into the radio to get the proper adjustment done. These are only a couple of examples of the need for a sig/gen with a calibrated output. The Squelch and SSB receive also require a calibrated signal with different output levels to adjust them correctly too.

So while the idea to use another radio to align the receive on another can be used in a situation where the radio is so out of whack that it gets you close is OK. But don't think that it will get you exact results. It won't. It is a dubious compromise.

Just sayin . . .
 
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The 1khz audio tone and the ~27mhz radio sig/gen are two completely different animals. The 1khz tone generator is OK to use for audio work; but one still needs a real sig/gen with a calibrated, adjustable output to do accurate receive alignments.
 
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Thanks some more, I'm after correct alignment.
So back to the orignal question, is there an afforable alternative for just 10 and 11M?
 
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I lost my last post?
Thanks some more, is there an affordable alternative to perform the above?
Most of the B&K stuff goes for high dollar on e-ba**.
Are there any other brands, models that will fit the bill to get started in 10 and 11 Meter.
 
The B&K stuff isn't the most expensive nor is it the most accurate that can be found. I got a Hp 8656B for $250, and that is the best one to get. If you can find one for that price that works, it is real lab-grade gear, as they usually sell for twice that much.

But even the B&K will work because it has a calibrated output. The B&K will drift off-freq a bit, but for $150 it will do the job fine once it is warmed up and you modify it so that you can hook up a lab-grade freq counter to it.
 
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Question for the inquisitive... What happens if you take the HP and feed the pre driver of a cobra with the HP set at a pilot carrier of 10 KHz. in the FM mode at full deviation? Be careful how you answer because not everyone will resist :)
 

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