[Elecraft] [qrp-l.org] Signal / RF generator

[Don Wilhelm]

Jerry,

I answered on the Elecraft reflector, but will repeat it here for those 
interested.

Since the question was about what signal generators we have, I thought I 
would add the list of what I have here - some have specific purposes 
while others are general purpose.

I have several signal generators.  The two most important properties of 
a signal generator (for me) are frequency stability and clean sine-wave 
output.  If one has attenuators, then control of the output level is not 
a requirement as long as the generator level is steady.
Generators that I have available
- A homebrew generator with about 10 dBm output (variable in steps down 
to about -20 dBm - the design is the dual range generator shown in 
Experimental Methods for RF Design.  This was built in an ARC-5 
transmitter frame so it has mechanical stability lots of bandspread with 
the geared tuning capacitor(s) drive. and covers from about 3 MHz to 50 
MHz.
-  A DDS vfo that is controlled by the parallel port on the workshop 
computer 100 Hz to 30 MHz in 1 Hz steps.  Very stable and no warm-up 
drift.  No level adjustment on the output, uses the AmQRP DDS kit as its 
basis.
- A high level generator as shown in the K1 and K2 manuals 
(Troubleshooting section).  I used a plug-in crystal so I can change 
input frequencies easily.
- The Elecraft XG2 for calibrating S-meters and doing MDS related 
measurements.
- An HP8640B - this is my main workhorse generator, it has very low 
phase noise, and is quite stable after a 2 hour warmup period plus it 
has AM and FM modulation and provisions for sweeping it if required.  It 
goes down to 500 kHz and up to 512 MHz.  It is very well shielded so 
there is no leakage and the output level can be adjusted from a high of 
+23 dBm to -140 dBm with its internal attenuator.
- In addition, I have my K2 and a few QRP transmitters which can also 
serve as a high level signal generator within the ham bands, and yes, I 
can use the output from my MFJ259B or my Micro908 antenna analyzers as a 
useful signal source in many cases.  The generator I choose depends on 
what I am trying to accomplish.

Get a copy of Experimental Methods in RF Design and turn to the 
Measurements chapter if you have a mind to build a generator, several 
are detailed there.

I might also mention that I have a LOT of 28.322 MHz oscillators if 
anyone wants to use one as a base for a signal generator (think about a 
divider followed by a Low Pass Filter.  I can mail one to you for $3.

73,
Don W3FPR



n0jrn wrote:
> Gang:              Considering the purchase of a signal generator for 
> aligning the projects in the shack.
>
> Looking on e-bay shows several low cost options.  Most are pretty old 
> and likely in need of some work.
>
> SO figure I would query the group to see what everyone else is using.
>
> IF your using a signal / RF generator,  what brand, model and options 
> are you using ???
>
> Was there a reason you choice the unit you have over some other ????
>
> Just curious
>
> 73         Jerry             N0JRN
>
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