[Elecraft] signal generator

[Jim Wiley]

Steve -

I am going to take a chance and assume that the DDS in your address 
means Doctor of Dental Surgery (A dentist). 


Comparing  Hakko 808 and a signal generator is an uncertain exercise at 
best.   The two instruments are used for quite different purposes.  The 
comparison might be likened to comparing dental floss and an X-ray 
machine.  Dental floss is used to remove unwanted material between 
teeth, a Hakko 808 is used to remove unwanted solder from circuit 
boards.   The X-ray machine is used to examine the patient's innards (to 
some degree or another) and the signal generator is used to examine a 
receiver's performance (or lack thereof). 


All that being said, my favorite signal generator is the Hewlett-Packard 
(HP) 8640B.  Working units, not necessarily "in cal", but certainly 
usable, are available for as little as $250 on eBay or at hamfests.  
New, these instruments were in the $12,000 to $18,000 range, depending 
on options and year of manufacture.  There are a number of other good 
instruments, some made by HP, and others by Fluke, Marconi, General 
Radio, Boonton, and others.  The basic things to look for are frequency 
coverage (500 KHz to 500 MHz  is adequate for most ham radio 
applications),  quality of the attenuator (for accurate  sensitivity 
measurements), modulation types (AM and FM preferred, but AM only will 
do for many uses),  frequency  readout accuracy (digital counters are 
nice) and  stability (phase locked oscillators or synthesizers are 
best).   There are other factors that can be important as well, such as 
phase noise and jitter,  maximum output capability, and protection from 
reverse power.   The HP 8640B (with various options) fits this bill 
nicely, but is not the only answer. 


I have seen hams use the most basic signal generators with skill and 
ingenuity to achieve remarkable results, and the basic signal generator 
offered by elecraft is an example of this.  Homemade equipment is often 
used successfully.  The ARRL handbook has some examples that might be 
useful.   Also, check flea markets and auctions for older Heathkit 
units.  While not anything close to the performance of professional 
grade units, they are often "good enough" for basic signal tracing and 
troubleshooting. 


Finally, signal tracing, as opposed to signal injection,  is usually 
accomplished with a device known oddly enough as a "signal tracer" - 
typically a device that can grab small signals and amplify them enough 
to drive a small speaker. Often including a Rf detector probe, they can 
be very useful in finding out where something has gone awry.  Signal 
Tracers and Signal Generators are often used together, with one 
supplying the signal to be traced, the other doing the tracing.


There are several good books on equipment servicing that can take you 
farther.  The ARRL lists a couple in their bookstore section, and again 
their handbook has some basic servicing tips. .


Good luck!


73

- Jim, KL7CC

 

Steve Harpole, DDS wrote:

>Anyone have any suggestions as to what brand , model of signal generator that is comparable in popularity as the Hakko 808 desoldering tool?  Curious as to what others use , if  they are into signal tracing..
>
>Thanks,
>
>Steve
>KQ4UB
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