- Amateur Radio (Ham Radio) Community

Call Search

New to Ham Radio?
My Profile

Friends Remembered
Survey Question

DX Cluster Spots

Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement

Reviews Categories | Tools & Test Equipment for the amateur radio work bench | HP-8640B Help

Reviews Summary for HP-8640B
HP-8640B Reviews: 9 Average rating: 4.9/5 MSRP: $Available used.
Description: This is a signal generator that covers 455kc to 510 mhz and is one of the best signal generator available on the used market from $400.00 to the $1000.00 range.
Product is in production.
More info: http://Sold use from
Email Subscription
You are not subscribed to this review.

My Subscriptions
Subscriptions Help

You can write your own review of the HP-8640B.

W5CRY Rating: 5/5 Nov 17, 2013 04:41 Send this review to a friend
Great Generator  Time owned: more than 12 months
I purchased an HP-8640B from an auction site some ten years ago and it has performed reliably, until recently, when the frequency display became erratic. Two known problems with this instrument is the little contacts on the Frequency/FM Selector Switch or cracked or broken gears in the assembly. After some research on the internet, I found Electronic Revisited. Bill the owner is an absolute encyclopedia of knowledge about the 8640. He was most helpful via email and offers an 8640B repair service. In the end he rebuilt my Switch Selector Assembly and my trusty 8640B is back to working great ! There is a gentlemen in Italy who is manufacturing new gears for the 8640B, I purchased a set just for future insurance and found them to appear to be very good quality.
AC5UP Rating: 5/5 May 21, 2011 21:47 Send this review to a friend
Built To Survive!  Time owned: more than 12 months
I have the Navy version configured with Option 323. Once you get past the bright yellow find-me-under-water case (which I repainted with Krylon dove grey) it's an intuitive generator that's very easy to use.

Mine was an ePray bargain that arrived DOA. Opened it up to find the cable harness between the RF PA and output attenuator had been unplugged. There is no way this just happened. Best guess is that's how they're de-milled prior to auction. I re-attached the harness, added a Ty-Rap to keep it that way, and it hasn't missed a beat since.

HP built these like Steven Spielberg built Jessica Rabbit. Absolutely outstanding. Spot-on dead accurate and stable -after- it has achieved run temperature which takes 30-45 minutes. The mil version does not have the PLL frequency lock so there is a slight amount of drift, but I've learned that mine always drifts downward in frequency. So I set it a tad high then let it drift through the alignment frequency while I tweak. The unit was intended to run 24/7.

For all I know there's something newer, synthesized, digital and so near perfection that it's a better buy than the 8640B, but you won't find anything built better or likely to outlive one.

The full set of books are available on the Agilent web site as a free download.
WA4AOS Rating: 5/5 Aug 28, 2010 11:16 Send this review to a friend
EXCELLENT GEN  Time owned: more than 12 months
I have a small business where I primarily restore R 390, R 390A and R 392 receivers. I own 3 of these generators, one for each bench and they are outstanding. There is a fellow out of TX named Gene who restores these beast and sells them on epray. His units sell for about $900 with 01, 02 and 03 options. The test equipment companies sell them for about the same but they are often dogs. Gene's units are clean and he does an excellent job getting them right.
These gens are rock solid and very clean. I have used them for experimental filter design work and could not be more pleased.
The one down side is many of the gears up front are special and made of plastic, It is common to find them cracked. I have a few parts queens on hand to rob from should I need to later.
I have worked on lots of very complex and well made electronic test gear, receivers and transmitters. The 8640B is probably the most well made piece of equipment that I have worked with. This unit was made for serious long term applications and will hopefully serve me for the duration.
W8AAZ Rating: 4/5 Mar 19, 2009 19:28 Send this review to a friend
Heavy but clean spectrum  Time owned: more than 12 months
I have used or owned these in the past quite alot. Both the mil. version and the commercial. Of course the mil. version does not have the freq.lock feature and requires a long warm up. And it is built like a tank. Nothing flimsy. HP's golden age of hi grade test gear. The thing has a UHF cavity oscillator for tuning, and divides it down for the lower ranges, thus lower freq ranges have less and less drift. For testing bandpass of receivers, the clean carrier is a boon. Some of the synthesized generators are not as clean. SO if you are testing a rx. for the minus 60 selectivity response, the noisier synth. units will give a falsely broad skirt response. Downside is the weight and size. IF you got the room for it, you can't go wrong with a good HP. Somewhat outdated in appearance and controls.
N4UE Rating: 5/5 Oct 24, 2008 17:02 Send this review to a friend
A 'standard'  Time owned: 3 to 6 months
Hi. I have a bunch of HP Signal Generators. Most are of the 606 and 608 vintage. Although excellent, the 608s lack coverage below 10 MHz. I came across my 8640B on ePay, er, eBay. The seller stated it was in good condition and "works as far as we can tell". What the heck, I did a 'Buy it Now', for pretty cheap. The unit was packed in spray in foam and arrived in perfect shape. The only thing wrong (!!!) was that the 'Fine Tune' control was not working. There was a label on the front stating so. I used it for a while in this state (which is not difficult) until I ran across an 8640B 'guru'. He told me that the 'fine tuning' was part of the cavity and was mechanical. Heck, I opened her up and lo and behold, there was NO shaft connecting the knob to the shaft on the cavity. There is an offset to these 2 shafts, which probably accounts for the broken/missing part. I found a short piece of vinyl tubing that was a press fit on both shafts and she's back in business.

The inside of these units are just scary - beautiful!!!
If I were to nit pick, I would rather have LCD display segments rather than those 'dots'.
Once you select your frequency and "Lock" it, it will stay there ALL week!!!

Wonderful! Wish I had bought one years ago!
By the way, ALL of it's Manuals are available FREE on Aligent's website. In PDF format, they are great. Just buy stock in a paper company first!!! ha ha


SV8YM Rating: 5/5 Sep 24, 2008 03:50 Send this review to a friend
A great classic  Time owned: more than 12 months
The HP-8640(A or B) may be a bit old, but for amateur radio purposes it just can't be beat! Its phase noise performance is exceptional, enabling dynamic testing of even the best receivers. All it requires is a bit of infrequent basic maintenance, and it goes on ticking - but even in case of trouble, it can be (relatively) easily repaired. A great instrument to own and a joy to use.
WN5EGO Rating: 5/5 Jan 27, 2008 12:10 Send this review to a friend
Great tool!  Time owned: more than 12 months
I use my HP-8640B (with options 001, 002, and 003)
to align my R-390 and R-390A receivers, among other duties. It's a fine gadget for that. It also has turned out to be useful in aligning more modern receivers, such as the Debeg E2000, with IFs up in the VHF.

One particularly useful dodge with the 8640B, when I want to get response curves for a device, is to
drive the 8640B's FM modulation input, in DC mode,
with a linear ramp, and use the same ramp as the X-axis drive on my 'scope.

The attenuator does down to tiny levels with great
accuracy, and the shielding is good enough that
the generator just doesn't leak.

One of the options takes my 8640B up to 1024 MHz
according to the specs and about 1200 MHz in practice; the bottom end is officially 500 KHz, and in practice about 440 KHz, which covers almost
all IF's I've ever had to deal with.

I wish I had another.
K7LZR Rating: 5/5 Sep 17, 2006 01:48 Send this review to a friend
Excellent  Time owned: more than 12 months
I've been using an HP 8640B for about 2 years for every type of servicing from alignments to receiver sensitivity tests. I find it to be a quality, professional grade instrument which offers great accuracy, stability, and output purity. These generators offer all of the needed features for most applications, and they are easy to service and maintain. These units are true bargain jewels.

K6DPZ Rating: 5/5 Jul 22, 2006 06:07 Send this review to a friend
One of the greatest units available for the price. .  Time owned: more than 12 months
We use these generators in repairing all types of radio communications equiptment AM and FM in our shop and has lived up to all expetations.very low phase and very high accuracy in sensitivity.measurments.And can be very stable with its phase lock has .1 uv to 3 volt output at 50 ohms.And some are available with reverse power protection.

If you have any questions, problems, or suggestions about Reviews, please email your Reviews Manager.