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OT: Test Equipment

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k0wa@swbell.net

OT: Test Equipment

If I were to buy a RF signal generator off of Ebay....what is a good one to buy? I don't want a WWII surplus RF signal generator and do not want the 10,000 dollar one either. I would like to have a transistor RF signal generator so that kind of leaves out the old Heaths and Eicos.

Does this august body of homebrew swamis have any suggestions?

Lee - K0WA

In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine?

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Jack Smith-6

Re: OT: Test Equipment

HP8640B is the generator of choice for (a) low phase noise and (b) more
or less affordable (in the $1K and less category.)

That being said, these generators are now well over 20 years old and are
notorious for mechanical problems associated with switches and tuning
gears. I would not purchase one unless you are prepared to do some work
on it. If a switch or two isn't broken when you buy it, it soon will be.
These are very complicated mechanically.

If your budget will stand it, I would purchase an HP8657B, or, as a
somewhat less desirable unit, an HP8567A. Both are synthesized signal
generators and are free of some of the problems that have been found
with their lower price brother generator, the HP8656. The phase noise
and spurious outputs of these synthesized generators are much inferior
to the 8640B. They are, however, fully synthesized, and can be remotely
controlled over an HPIB interface, neither of which is the case for the
8640B.

I have a pair of 8640Bs and a pair of 8657A's. Both 8640B's have
mechanical problems that, fortunately, I can live with as I am not all
that good at complicated mechanical repair work.

Jack K8ZOA

Lee Buller wrote:

>
> If I were to buy a RF signal generator off of Ebay....what is a good
> one to buy? I don't want a WWII surplus RF signal generator and do
> not want the 10,000 dollar one either. I would like to have a
> transistor RF signal generator so that kind of leaves out the old
> Heaths and Eicos.
>
> Does this august body of homebrew swamis have any suggestions?
>
> Lee - K0WA
>
>
> In our day and age it seems that Common Sense is in short supply. If
> you don't have any Common Sense - get some Common Sense and use it. If
> you can't find any Common Sense, ask for help from somebody who has
> some Common Sense. Is Common Sense divine?
>
> ------------------------------------------------------------------------
>
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> You must be a subscriber to post to the list.
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Don Wilhelm-4

Re: OT: Test Equipment

In reply to this post by k0wa@swbell.net

Lee,

Assuming you want quality without a lot of expense, I would wait until
an HP 8640B shows up. 500 kHz to 512 MHz CW or AM (some have FM
capabilities). They are well shielded and the output attenuator is
calibrated - goes from +20 dBm to -130 on the fixed attenuator and can
be reduced to -140 dBm.
There is some warmup drift that lasts for as much as 2 hours, but they
do settle down to a very stable frequency.

There may be newer signal generators that have the same performance
specs, but this is an old favorite of many. The only major problem I
know about is reports of broken gears - mine does not suffer from that
problem (yet).

73,
Don W3FPR

Lee Buller wrote:

alsopb

Re: OT: Test Equipment

The K-3 uses direct digital synthesis to get its frequencies, why not you?

For those of you who want to do a little HBing . There is a direct
digital synthesis RF generator kit from the below for under $30.
Upper audio to 60MHz with at least 1 Hz resolution. Fits in a tiny minibox.

http://www.amqrp.org/kits/dds60/

You need to be able to assemble SMT stuff. You also need to provide an
attenuator since it puts out several volts.
There is a free parallel port based program one may use to generate the
programming word. It can run for 10 hours on an eight pack of
rechargable AA NIMH batteries .

Several alternative ways of providing the programming word are given in
the documentation. The alternative ways involve PIC's and some
programming-- not for everyone. I threw together an alternative using
a BASIC STAMP, STAMP floating point processor, an LCD display and
pushbuttons for input. Works for me.

The unit drifts initially about 50 Hz and settles down to be as stable
as the K3 in about half an hour.

Recently used it ( + 80 db attenuation) and the FILTER tools program
described in posts on this reflector to generate a bunch of filter
plots. Worked very nicely. Held it's frequency within 1Hz for the
whole series of filter runs.

I have no financial interest in AMQRP or the DDS-60 product.

73 de Brian/K3KO

Don Wilhelm wrote:

>Lee,
>
>Assuming you want quality without a lot of expense, I would wait until
>an HP 8640B shows up. 500 kHz to 512 MHz CW or AM (some have FM
>capabilities). They are well shielded and the output attenuator is
>calibrated - goes from +20 dBm to -130 on the fixed attenuator and can
>be reduced to -140 dBm.
>There is some warmup drift that lasts for as much as 2 hours, but they
>do settle down to a very stable frequency.
>
>There may be newer signal generators that have the same performance
>specs, but this is an old favorite of many. The only major problem I
>know about is reports of broken gears - mine does not suffer from that
>problem (yet).
>
>73,
>Don W3FPR
>
>Lee Buller wrote:
>
>
>>If I were to buy a RF signal generator off of Ebay....what is a good
>>one to buy? I don't want a WWII surplus RF signal generator and do
>>not want the 10,000 dollar one either. I would like to have a
>>transistor RF signal generator so that kind of leaves out the old
>>Heaths and Eicos.
>>
>>Does this august body of homebrew swamis have any suggestions?
>>
>>Lee - K0WA
>>
>>
>>In our day and age it seems that Common Sense is in short supply. If
>>you don't have any Common Sense - get some Common Sense and use it. If
>>you can't find any Common Sense, ask for help from somebody who has
>>some Common Sense. Is Common Sense divine?
>>
>>------------------------------------------------------------------------
>>
>>_______________________________________________
>>Elecraft mailing list
>>Post to: [hidden email]
>>You must be a subscriber to post to the list.
>>Subscriber Info (Addr. Change, sub, unsub etc.):
>> http://mailman.qth.net/mailman/listinfo/elecraft
>>
>>Help: http://mailman.qth.net/subscribers.htm
>>Elecraft web page: http://www.elecraft.com
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>>
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>>
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>

Joe Planisky

Re: OT: Test Equipment

In reply to this post by k0wa@swbell.net

If you can get by with ham-band only frequency coverage, what about
using the K3 + KXV3 + some attenuators as a signal generator? You
could even forgo the KXV3 if you have attenuators that can handle 100mW.

73
--
Joe KB8AP

On Jan 22, 2009, at 11:02 AM, Lee Buller wrote:

w2bvh

Re: OT: Test Equipment

In reply to this post by k0wa@swbell.net

You might want to check out the siggen in this months QEX. It has I/Q
output up to 200MHz. Output level is settable and controllable. And if
you need low phase noise, it has provision for an external low phase
noise clock. It's also small and light; can be controlled by a pc or
external microprocessor.

Lenny W2BVH

Lee Buller wrote:

M0XDF

Re: OT: Test Equipment

In reply to this post by Don Wilhelm-4

There is one on eBay right now, with 14hr to go at $227
<http://cgi.ebay.co.uk/HP-8640B-SIGNAL-GENERATOR_W0QQitemZ280304509503QQcmdZViewItemQQptZBI_Signal_Sources?hash=item280304509503&_trksid=p3286.m63.l1177
>
73 de M0XDF, K3 #174

--
Why should I fear death? If I am, death is not. If death is, I am not.
Why
should I fear that which cannot exist when I do?
-Epicurus, philosopher (c. 341-270 BCE)

On 22 Jan 2009, at 19:31, Don Wilhelm wrote:

> Assuming you want quality without a lot of expense, I would wait
> until
> an HP 8640B shows up.

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Phil Salas

Re: OT: Test Equipment

In reply to this post by k0wa@swbell.net

Not sure what you plan on using it for, but you might just be happy with your antenna analyzer output. Antenna analyzers I've looked at (MFJ-259B, AIM4170B, AA-200) have a pretty well regulated RF output level across their full range. The MFJ-259B and AA-200 have 2Vp-p output levels, and the AIM-4170B has about a 20mVp-p output level. The MFJ-259B drifts around a lot, and needs to be run from a fixed voltage external power supply for best frequency stability after warm-up. The AIM4170B and AA-200 are synthesized and let you sweep as well. The AIM4170B even lets you zero its accuracy to WWV. Then all you need are some step- and/or fixed-attenuators to get the level to where you want it. I'm sure that the phase noise isn't HP-quality, but you can do a lot of normal ham-stuff. I use the high level outputs with an oscilloscope for filter work.

Phil - AD5X