On Mon, 19 Mar 2012 22:42:47 +0100, "Antonio I0JX"
wrote:

Frequency measurement results a
- Just turned on. Frequency = 5.000 MHz Delta F = 0
- 15 minutes after. Delta F = -98 kHz (drift = 6.5 kHz per minute)
- 30 minutes after. Delta F = - 116 kHz (drift = 3.7 kHz per minute)
- 45 minutes after. Delta F = -132 kHz (drift = 2.9 kHz per minute)
- 60 minutes after. Delta F = -141 kHz (drift = 2.3 kHz per minute)
- 75 minutes after. Delta F = -147 kHz (drift = 2.0 kHz per minute)

150KHz of 5000KHz is 3% drift. That's within the specified 5%.

Drift is too high for any practical use.

Really? I used a 3312A in the 1970's to do type certification on
various radios. It was perfectly suited for running as an audio sweep
generator, or for making manual plots of various devices frequency
response. The only time I ran into trouble was when I had to generate
a specific frequency tone, such as the Bell system test frequency of
1004Hz. I just connected a frequency counter and reset the dial every
time it tried to move.

Whether it's practical depends on what you are doing with it. What is
your application? If it's generating a 5MHz RF signal to radio
receiver, forget it. Not only is it not stable enough, but the AM and
FM noise produced by the function generator is truly awful.

But before throwing it in the waste basket (as I'll probably do in the end),

I think you'll find that it's a rather useful piece of equipment for
audio, not RF. I suggest you keep it (or sell it). Checking eBay
completed listings, they were recently sold from $70 to $150.
http://www.ebay.com/sch/i.html?_skipfnorm=1&_nkw=HP3312A&_in_kw=1&_ex_kw=& _sacat=0&_okw=&_oexkw=&_adv=1&LH_Complete=1&_udlo= &_udhi=&_samilow=&_samihi=&_sadis=200&_fpos=&_fsct =&LH_SALE_CURRENCY=0&_sop=12&_dmd=1&_ipg=50

I would be curious to know the experience of other people having that
generator or a similar one using the same (analog) frequency generation
principle (charging a capacitor at constant current). Do all of them behave
more or less the same? Is my unit faulty?

It's not faulty and all such analog instruments drift and are noisy.
Please disclose your application and I can offer a class of suitable
instruments, or a specific device that I like.

My (messy) bench:
http://802.11junk.com/jeffl/pics/home/slides/BL-shop6.html
I count 7 different signal sources on the bench. There are about 10
more scattered in different corners. One signal source just can't do
everything.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS