HP 8405A Vector Voltmeter Partial Repair

[@karlfell3768]

Just a beautful piece of old school test equipment. Keep the videos coming. Karl

[@tgsoapbox]

Thanks - It really was a piece of art internally.

[@Testequip]

Thanks for a very interesting video. I have both the HP8405A and the HP3575A Gain Phase meter 1Hz to 13MHz (aka Vector Voltmeter). So I can measure from 1Hz to 1Ghz. I have the relevant application notes albeit it would be great if there was a few ideas on other applications. Keep up the good work!

[@tgsoapbox]

Glad you enjoyed the video - These are great tools for amateur radio people because they cover the most popular bands - Attenuators, filters, amp design, antenna work - Pretty useful.

[@alandoherty8279]

Hi, very interesting although I can't see me ever having a use for it. Can't wait to see what else it can do.. Keep "em" coming.. Cheers

[@tgsoapbox]

Thanks Alan - I have an 8714C VNA that covers 0-3GHz so I probably won't use this in anger but it's a fantastic piece to add to the collection.

[@harbselectronicslab3551]

A great old bit of gear I still enjoy dragging out to do Coax Loss measurements......I have the later 8505A

[@tgsoapbox]

Good to hear - I just picked up the 8508A so I'm going to do a video on that in a week or so.

[@amorim317]

don´t you need a dual coupler to make the measurements with the vector voltmeter?

[@tgsoapbox]

Only if you're trying to measure the reflected signal (as in return loss/vswr). For transmission measurements the second channel acts like the incident port on the coupler.

[@amorim317]

you are right, i thought you were trying to measure impeadance. thanks for answering

[@tgsoapbox]

No problem. Thanks for watching and commenting.

[@douro20]

Good luck trying to find just an air line by itself with N connectors on both ends; I've found it is very difficult.

[@pa4tim]

I have airlines from GR and a whole box of GR adapters to connect them to N, bnc etc Very handy system. I use the GR stuff on all my gear. I have attenuators, adapters, airline, T's, mixers, etc All GR-874. Besides that I have some GR-900 stuff including a beautifull GR-900 slotted line, a selection og GR-900 adapters and some airlines. Most GR-874 stuff I found for near to nothing at ham-fests. Most hams have no clue what it is.

[@tgsoapbox]

According to the manual I need a 874-LK20L 20cm Constant Impedance Adjustable Air Line to do the performance checks. I'll also need 2 874-QNP N Male to GR adapters. I'll have to check closer because I might be able to get away with a fixed air line as those are way more plentiful.

[@pa4tim]

Those are a bit harder to find. www.pa4tim.nl/?p=4686 here you see a part of my GR adapter stuff

[@tgsoapbox]

Nice - I've been eying a GR slotted line as well so I might have to just pull the trigger on these later this month.

[@Testequip]

There are no manuals for this instrument on the net. I do have a hard copy of the circuit diagram for this instrument. If you require a soft copy, don't hesitate to ask.

[@tgsoapbox]

Thanks - Appreciate that - It does look like Keysight has scanned and uploaded a full manual but you can also get it from Artek Manuals with way better schematics (usually) than the Keysight downloads.

[@Testequip]

@@tgsoapbox Thanks. I Googled a few years ago but found nothing - I Googled again and found the manuals at BAMA

[@tgsoapbox]

@@Testequip NP Glad you got them.