HP 608c - Page 1
Forum section: electronics / rf-microwave

author: neo
author_rank: Super Contributor
timestamp: April 19, 2017, 06:33:36 pm
content: I should note i have no clue where i should post this so i chose here because it is vhf related, move it if i guessed wrong. I found a HP 608c rack mount for free a couple months back and it lights up and looks as if it is working, i didn't turn it on any longer than a couple of seconds. I have no clue how to test it and have no clue what i would do with it if it did work. I have three questions. How should i test it? Should i test it? Is there any use for it outside of radio use?

author: Tony_G
author_rank: Super Contributor
timestamp: April 19, 2017, 07:16:23 pm
content: You can get the manual at K04BB.com:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/HP_608_VHF_Signal_GeneratorSection 4-3 is what you're after.TonyG

author: N2IXK
author_rank: Frequent Contributor
timestamp: April 20, 2017, 02:01:58 am
content: Vintage gear like that will often benefit from a slow ramp-up of power using a variac, rather than just turning it on after sitting for possibly decades. Gives electrolytic caps a chance to "reform" a bit, reducing the chance of releasing the magic smoke from the rest of the power supply.It is a high quality bit of lab gear, but a power-hungry boatanchor by modern standards. But if you need a source of VHF test signals for whatever you are working on, it is still perfectly usable if still operational.

author: neo
author_rank: Super Contributor
timestamp: April 20, 2017, 09:57:16 am
content: Let me hazard a couple more complicated question (hazard being because i have no clue what im talking about). I need a connector whose name i don't know, type of connector for this thing? PL259 didn't fit the center pin was too big im guessing it would be N male? A 50 ohm high wattage dummy load, and then i can connector a scope probe to it and then see waveforms on my scope, correct?

author: voltz
author_rank: Frequent Contributor
timestamp: April 20, 2017, 10:43:55 am
content: From the manual, the RF output looks like a N Type connector. So you need a male N type plug.Viewing the sine wave from the generator on a scope will only work if your scope has a capable bandwidth to handle it. Start looking at the lowest frequencies first (10Mhz). You should see something. Going higher frequency and the trace will reduce. Your connecting cable (or probe) has a frequency limit too. So dont expect to see anything at the high end (470Mhz).You dont need to connect a dummy load. Its not a transmitter with watts of output. The output will be low. More like micro watts.

author: neo
author_rank: Super Contributor
timestamp: April 20, 2017, 11:14:43 am
content: Quote from: voltz on April 20, 2017, 10:43:55 amI expected that given that my scope and probes are 100 MHZ but if the thing can put out 10-90 MHZ it would prove that it works at least in the low end. Thank you for mentioning it.http://www.ebay.com/itm/N-Male-Jack-to-BNC-Female-plug-RF-coaxial-Adapter-RF-Connector-USA-/141030328117?hash=item20d6100735:g:o9cAAMXQiFxR~sGIwould this be the right adapter?

author: Tony_G
author_rank: Super Contributor
timestamp: April 20, 2017, 03:04:17 pm
content: Yes - You want an N to BNC adapter.It looks like it puts out a max of around 20mW with the calibrated range up to 5mW so you should be find to just connect it directly to the scope via either aT adapterwith a50 ohm terminatoror a50 ohm feed through terminatorif you want the scope readings to match what is on the output power dial. If you don't care then what you'll see on the scope will be twice what you see on dial.TonyG