EMRFD Message Archive 8356
Message Date From Subject 8356 2013-03-17 19:21:34 Jerry Haigwood I new a generator
I am wanting to buy a better generator that I currently have. I'd really
like a nice clean HP8640B but I can't afford one. So, what do you
recommend? I am told that Wavetek 3010 is a nice generator for about $250.
Has anyone used one of these? Come on guys help me out here! Tell me what
you are using and why you like it.
Jerry W5JH
"building something without experimenting is just solder practice"
[Non-text portions of this message have been removed]8357 2013-03-17 19:23:42 Jerry Haigwood Re: I need a new generator
Jerry W5JH
"building something without experimenting is just solder practice"
8358 2013-03-17 21:28:36 Kerry Re: I need a new generator
I do note that its frequency steps are 100Hz; this is not fine enough for crystal characterisation if you need it for that (although other methods of crystal measurement such as the G3UUR method do not require a generator).
100Hz is also rather coarse if you want to examine narrow filters carefully.
It was the 100Hz step of my otherwise excellent R & S SMS that impelled me to supplement it with a HP 8657B and, eventually, an N2PK VNA and a DG8SAQ VNWA for work of this kind.
Signal generators are something that "you get what you pay for"; there are certainly price variations for each model/type (just look at the great range of asking prices for, eg, 8640s on ebay and elsewhere) but a good generator will still cost money.
The 8640 has something of "cult" status and rightly so; a very fine instrument. But this status often tends to elevate the asking price for an instrument that is now quite old.
There are, however, people who specialise in refurbishing and selling 8640s; not cheap but there is a warranty and some peace-of-mind.
I think that the 8601 you mentioned earlier would be OK at a low price; say $100. General asking price seems to be more than that but they are 40+ years old. Buy cheaply with the expectation of moving up later.
My 25-year progression through signal generators was, as near as I can remember;
Home-made GDO; Marconi TF144H; Rohde & Schwarz SMS; Home-made DDS generator from short-form kit; HP 8657B.
Kerry VK2TIL.8359 2013-03-18 02:56:56 Leon Heller Re: I new a generator 8360 2013-03-18 20:18:19 Jerry Haigwood Re: I need a new generator
I am looking at a Wavetek SG-1170/U which is a military version of a
Model 3001. It has a frequency range of .001 to 520 MHz in 1KHz steps. It
also has a vernier control which allows complete frequency coverage. It has
a calibrated attenuator and the output is +13 to -137 dbm. It also has
internal 400 and 1000 Hz AM and FM modulation with an external modulation
input. The frequency is referenced to a 10 MHz crystal oscillator.
Frequency accuracy is within .001%. The phase noise is -100dbc/Hz at 20
KHz offset which is not nearly as good as the HP8640B. The overall size is
12 x 5.25 x 13.75 inches (30.5 x 13.3 x 34.9 cm) and it weighs 24 lbs
(11.2kg). It is a lot smaller than my old HP606 generator which I no longer
use - it is just too BIG. I am seriously considering this generator. The
guy that has it for sale rebuilds and sells Wavetek generators. He says
that this one has been burning in for 250 hours and is doing well. I think
it is a lot of generator for the price ($235 USD).
Jerry W5JH
"building something without experimenting is just solder practice"
8361 2013-03-18 20:31:50 Jerry Haigwood Re: I new a generator
The Marconi 2019A looks to be a really nice generator. They also
appear to sell in the $400-800 USD range. It is something I can dream
about. ;-)
Jerry W5JH
"building something without experimenting is just solder practice"
8362 2013-03-18 20:34:54 Jerry Haigwood Re: I need a new generator
I looked up the HP8657B and it is a really nice generator! It seems to
sell for about $900 on ebay which is not a lot more than the HP8640B sells
for.
Jerry W5JH
"building something without experimenting is just solder practice"
8363 2013-03-18 22:50:40 Kerry Re: I need a new generator
Model 3001. It has a frequency range of .001 to 520 MHz in 1KHz steps. It
also has a vernier control which allows complete frequency coverage. It has
a calibrated attenuator and the output is +13 to -137 dbm. It also has
internal 400 and 1000 Hz AM and FM modulation with an external modulation
input. The frequency is referenced to a 10 MHz crystal oscillator.
Frequency accuracy is within .001%. The phase noise is -100dbc/Hz at 20
KHz offset which is not nearly as good as the HP8640B. The overall size is
12 x 5.25 x 13.75 inches (30.5 x 13.3 x 34.9 cm) and it weighs 24 lbs
(11.2kg). It is a lot smaller than my old HP606 generator which I no longer
use - it is just too BIG. I am seriously considering this generator. The
guy that has it for sale rebuilds and sells Wavetek generators. He says
that this one has been burning in for 250 hours and is doing well. I think
it is a lot of generator for the price ($235 USD).
****************************************************
That sounds like good value.
I suppose that, if you need a frequency readout finer than 1 kHz, you can use a frequency counter and adjust the vernier.
The phase noise isn't as good as other generators but I wouldn't be too concerned; I think it will be fine for 99.9% of general work.
Phase noise specs are a bit of a "mine's better than yours" thing these days. :)
All good generators are heavy and bulky; there's no substitute for mechanical rigidity and good shielding. My "ancient" TF144 weighs 75 lbs whilst my "modern" 8657B still weighs 45 lbs.
Much of the weight saving is probably in the power supplies; switch-mode vs linear.
The Wavetek does sound good to me at that price but it's your call!
Kerry VK2TIL.8368 2013-03-19 21:51:55 Dave Hartman - AC... Re: I need a new generator 8370 2013-03-19 21:51:55 Paul Re: I new a generator
The FM-10 is my primary generator, synthesized and amateur radio type calibrated output level.
de Paul, W8AEF
8374 2013-03-19 21:51:56 agustintomasferra... Re: I need a new generator
One of my monitors, shows the legend "burn in" when there is no signal sent to it. I presume both things are not related.
8376 2013-03-19 23:01:32 Kerry Re: I need a new generator
*****************************************************
No idea what it means in the context of your monitor.
In the context of signal generators and electronics generally (and a few other fields), "burning in" means that it has been running (in this case for 250 hours) and has not exhibited any problems.8382 2013-03-21 19:58:45 Jerry Haigwood Re: I need a new generator
Well I finally broke down and purchased a HP8640B with options 001,
002, 003. I found one on ebay for $350. The price of these things seem to
run from about $375 for one needing work to $1000 or more (one was listed
for $1500 as is no warranty). I am amazed at how these generators hold
their price. There seems to be a "cult" following for this generator. It
is a nice generator but for $1000 you could get something a little newer and
maybe nicer. So, I now have a 8640Jr generator designed by W7ZOI, and the
big brother HP8640B. My wife says I have to start selling off all the stuff
I no longer use. ;-)
Jerry W5JH
"building something without experimenting is just solder practice"
[Non-text portions of this message have been removed]8385 2013-03-21 21:42:41 Kerry Re: I need a new generator
Near-enough to $14000; the average price of a new car was $9000 at the time whilst the median US house price was about $85000.
The present-day support for these fine instruments is astonishing; should something go wrong, most parts, either NOS or third-party manufactured (eg the output amplifier) seem to be available.
Kerry VK2TIL.8387 2013-03-22 18:24:23 AD7ZU Re: I need a new generator
congrats on your new generator... but realize to do all those complex receiver IMD/IP3 measurements you are going to need 2 generators!
Randy
AD7ZU
________________________________
8388 2013-03-22 18:24:23 Jim Re: I need a new generator
That's a super deal on that sig generator. Congratulations.
There's a guy who advertises on ebay who does tune-ups and partial cals on 8640s, as well as some repairs if he has the parts. He's very good at what he does, and very reasonable too. I can dig out his name if anybody needs, but the usual ebay search should turn him up.
73
Jim N6OTQ
>________________________________
>8389 2013-03-22 19:47:09 Jerry Haigwood Re: I need a new generator
The second generator is going to have to wait for a while…
Jerry W5JH
"building something without experimenting is just solder practice"
8390 2013-03-22 22:29:01 Ashhar Farhan Re: I need a new generator
no one wants to ship them to India.
Instead, a handful of crystals, a free running oscillator is what I
use. The si570 sweeper is not harmonically clean enough. How does one
go about producing harmonically clean signals?
- farhan
On 3/23/13, Jerry Haigwood <jerry@w5jh.net> wrote:
> Randy,
>
> The second generator is going to have to wait for a while…
>
> Jerry W5JH
>
> "building something without experimenting is just solder practice"
>
>
>
>
>
>
>
>8391 2013-03-23 00:18:05 Kerry Re: I need a new generator
http://i47.tinypic.com/rlg681.jpg
This was before I added a LPF but after I replaced the MMIC output amplifier with a 2N5179/2N5109 discrete amplifier.
They can be made to sweep (eg http://www.vk5tm.com/homebrew/dds/dds.php ) but the output drops as frequency rises so the results will not be good.
I went through all this and finally built an N2PK VNA and a DG8SAQ VNWA.
I see that a kind soul in Europe is offering to supply parts for the N2PK VNA to people outside the US; http://groups.yahoo.com/group/N2PK-VNA/message/7714
The DG8SAQ VNWA is no longer available as a kit; assembled instruments may be purchased; cheap compared to Agilent etc instruments but still not inexpensive.
Kerry VK2TIL.8392 2013-03-23 01:00:47 Dave Re: I need a new generator
their D/A converters are 14 bit vs 10 bit. They are also not much more
expensive.
Dave - WB6DHW
<http://wb6dhw.com>
8393 2013-03-23 01:03:11 Dave Re: I need a new generator
You could put switchable LPF's after the Si570. The even harmonics
should be pretty low, especially if you use the LVDS or LVPECL versions
and utilize both outputs. It is a square wave, so the odd harmonics are
strong
Dave - WB6DHW
<http://wb6dhw.com>
8394 2013-03-23 07:34:30 Mike Czuhajewski Re: I need a new generator
>spec sheet I have, cost new $12000...
of old equipment, but don't forget to factor in the effects of
inflation since a one dollar bill buys a lot less now than it did a
couple of decades ago. According to the 1991 HP catalog, the last one
in which this item was offered, the base price was $14,600 USD and
with the 3 options mentioned it rose to $16,910.
Plugging that number into an online consumer price index (CPI)
calculator shows that it is the equivalent of $28,413 in 2012 dollars.
That makes the $325 purchase price even better! (Whenever I drag home
some bargain test equipment I like to tell my wife what it cost when
new, corrected for inflation, to show what a great bargain it is. She
never falls for it, though; it's still just another thing cluttering
up the house.)8397 2013-03-23 10:06:50 Gene Dorcas Re: I need a new generator
in my office. Of course I don't consider ham rig and electronic test equip
junk. To me it's priceless !!!
Gene, W5DOR
8407 2013-03-23 13:17:32 Jim Re: I need a new generator
Keep the list where you keep the deed to your house. If you're like many of us, your shop equipment is worth as much as your car...and although it's not a fair comparison, if you look at the "new" price of test gear and adjust for inflation (as was recently shown here on an HP8640B), you may find that the new cost of your "junk" is substantially more than the new cost of your house.
I was shocked to see that the new price of my "junk" was well over three times the price of my house.
So I sold the house and kept the junk.
73
Jim N6OTQ
>________________________________
>8411 2013-03-23 17:43:36 Leonard Re: I need a new generator 8431 2013-03-31 18:16:13 Kirk Kleinschmidt HC-49U vs. HC-49US XTALS for crystal filters?
I just bought 100 9-MHz crystals from a Chinese auction listing so I'd
have a bunch on hand to build crystal filters (now that discrete,
non-SMD crystals seem to be all but disappearing)... As pictured and
described, the units were HC-49U. As delivered, they were the "shortie"
HC-49US units.
I'm wondering if there's any practical difference between the two types when it comes to building filters?
I seem to recall that there was...but I just can't remember!
Thanks,
--Kirk, NT0Z
My book, "Stealth Amateur Radio," is now available from
www.stealthamateur.com and on the Amazon Kindle (soon)
>[Non-text portions of this message have been removed]
8435 2013-03-31 18:28:53 Nick Kennedy Re: HC-49U vs. HC-49US XTALS for crystal filters?
part numbers. Their Q measured pretty good in comparison to standard HC49.
You see them used in filters sometimes where space and height are limited,
such as in Steve Weber's ATS-3.
73-
Nick, WA5BDU
[Non-text portions of this message have been removed]8441 2013-03-31 22:35:48 Kerry Re: HC-49U vs. HC-49US XTALS for crystal filters?
Very good crystals (say Q=200 000) seem to have vanished; the best Q I see (rarely often enough to make-up a good set) ) is about 150 000, I'm happy if I see some at around 100 000 and I see Q down to 40 000 sometimes.
I can't bear to read the section in EMRFD in which Wes mentions using crystals with Q = 240 000! :(
Kerry VK2TIL.8445 2013-04-01 13:05:57 boblarkin02 Re: HC-49U vs. HC-49US XTALS for crystal filters? 8446 2013-04-01 13:34:41 Kerry Re: HC-49U vs. HC-49US XTALS for crystal filters?
These are not available in VK; they can be ordered from Digikey, Mouser etc but the shipping charges are horrendous.
They seem to pop-up on ebay occasionally so I will keep a lookout for them.
Kerry VK2TIL.