Show us your Grip Dip / Wave Absorption Meters - Page 1
Forum section: electronics / rf-microwave

author: vinlove
author_rank: Frequent Contributor
timestamp: July 28, 2019, 12:16:25 pm
content: Are they useful in RF work?Are they still in use a lot?How are you using them? How often?Show us your Grid Dip / Wave Absorption meters. Thanks.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: July 28, 2019, 12:24:27 pm
content: Haven't used it for a while but here it ishttp://home.alphalink.com.au/~parkerp/projects/projdip.htm

author: vinlove
author_rank: Frequent Contributor
timestamp: July 28, 2019, 12:47:30 pm
content: Great stuff, very interesting. Thank you for your link.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 28, 2019, 02:02:50 pm
content: James Millen PN# 90651. Ad from the 1957 Radio Amature's Handbook. It was designed to run down to 1.7MHz but you can see I made up a coil to get me into the AM broadcast band .I have attached a PDF I made for it in case it may be helpful to someone.

author: vinlove
author_rank: Frequent Contributor
timestamp: July 28, 2019, 02:19:07 pm
content: Great looking meter. Looks like high quality stuff.I just acquired a Heathkit GD-1U, and it seems working fine. I did tune it to around 200kHz, and my LW radio was receiving the signal. Really impressed. It comes with 4x coils which covers 50Khz - 250Mhz or something like that.

author: StuartA
author_rank: Regular Contributor
timestamp: July 29, 2019, 08:48:50 pm
content: A couple of years ago, there was a very active thread on GDO's on the UK Vintage Radio Repair and Restoration forum.After about two weeks of discussion, with contributions from people in a number of countries, the concensus seemed to be that the Millen GDO (often referred to as the "Megacycle Meter") might well have been the best GDO ever made (and very many models of GDO have appeared over the years). I think that the same assessment has been made elsewhere on the net. Quite why it attracts so much positive comment is hard to say. It is slightly unusual in that it uses an Acorn valve. Whatever the reason, it does seem that Millen hit the 'sweet spot' of GDO design and construction. The manuals for it are easily findable on the web. Acorn valves are still obtainable, so making your own version would not be hard.

author: 9aplus
author_rank: Regular Contributor
timestamp: July 29, 2019, 09:16:40 pm
content: This is schematic of my old KYORITSU 126 GRID-DIPPER, after repair.Original transistor in oscillator gone west, therefore modern 2N2222Now working from 250 kHz up to more than 146 MHz

author: tautech
author_rank: Super Contributor
timestamp: July 30, 2019, 03:25:51 am
content: SVA1015X

author: edavid
author_rank: Super Contributor
timestamp: July 30, 2019, 03:43:30 am
content: Quote from: StuartA on July 29, 2019, 08:48:50 pmYou are actually describing the Measurements 59, not a Millen GDO.Here's the thread that you mentioned:https://www.vintage-radio.net/forum/showthread.php?t=142437

author: StuartA
author_rank: Regular Contributor
timestamp: August 02, 2019, 10:14:29 pm
content: Quote from: edavid on July 30, 2019, 03:43:30 amYou are 100% correct - I am having yet another "Senior Moment". And...while I recall great enthusiasm for the Measurements 59, I don't recall the Millen (or anything else) getting so much support

author: Bud
author_rank: Super Contributor
timestamp: August 04, 2019, 02:35:13 am
content: Simpson 77

author: vinlove
author_rank: Frequent Contributor
timestamp: August 05, 2019, 09:01:57 am
content: Great posts !!I am using my GDO as a signal generator, and seems working OK.

author: richnormand
author_rank: Unknown
timestamp: August 08, 2019, 06:52:38 pm
content: Here is my Heathkit GD-1B grid dip meter measuring a 8.2MHz security tag from a store...Uses a 6T6 tube and covers 2 to 250MHz.

author: w2aew
author_rank: Super Contributor
timestamp: August 09, 2019, 05:53:51 pm
content: Here's mine. I built this in the late 70s...

author: StuartA
author_rank: Regular Contributor
timestamp: August 12, 2019, 12:55:45 am
content: Heathkit produced a number of GDO's, initially with valves (tubes) and then transistors, but they also did one version using a tunnel diode. I think the model number was HM10. While the various other models seem to have survived to the present time, I've never encountered one of the tunnel diode models. Can anyone surprise me.S

author: richnormand
author_rank: Unknown
timestamp: August 12, 2019, 01:47:43 am
content: Here it is:

author: StuartA
author_rank: Regular Contributor
timestamp: August 12, 2019, 02:44:37 am
content: That is very neat! Is that your unit or are you just pointing us at the Youtube video (I think it was a US accent not Canadian)? A couple of years ago, I tried to build the oscillator circuit of the HM10. The tunnel diodes I had were some very old devices which showed good DC characteristics, but I couldn't make them oscillate. As I recall, there were some Russian tunnel diodes selling on ebay at the time. It's now on the list of "Things I must try Again....Sometime".S

author: chrisl
author_rank: Regular Contributor
timestamp: August 12, 2019, 03:51:16 am
content: I built a FET Dip Meter back in the 70s and used a lot for tuning TX/RX coils and antennas.Then I bought a DM-81 Dip Meter from Kenwood early in the 80s and used for many years.Once I got my spectrum analyzers and vector network analyzers I have not used the dip meter but it is still fun to look at it once in a while....

author: vinlove
author_rank: Frequent Contributor
timestamp: August 12, 2019, 09:47:35 am
content: I also have a LOWE FX-1 dip meter. It also detects RF in the vicinity.

author: richnormand
author_rank: Unknown
timestamp: August 12, 2019, 10:56:48 pm
content: Quote from: StuartA on August 12, 2019, 02:44:37 amJust pointing at the youtube video as it was the most informative one.Mine is the Heathkit GD-1B a few post earlier.

author: edigi
author_rank: Regular Contributor
timestamp: August 15, 2019, 12:00:25 pm
content: My version is pretty new (just a little bit older than 3 decades) and pretty unique (a single copy exists from it).I don't even know from where I've got the schematic, although it was built by me. Actually this is the second version and I liked the first one better. Housing is from circuit board. Not a very nice job I must admit, but it worked (in fact still works).Around that time I've used GDOs (O for oscillator) a lot (with interchangeable coils that I could not find and strangely also paper scale is for HF only in this version).With the advent of NanoVNA, SDR and affordable SAs probably it won't see much use any time soon (maybe ever).We just have to move on with the technology changes.

author: StuartA
author_rank: Regular Contributor
timestamp: August 16, 2019, 06:51:58 pm
content: Well, the range of people interested in ham radio ranges from pure hobbyists like me, to people who are highly qualified professional engineers. The NanoVNA may be fine for the latter, but the hobbyist may well be happier with a good (simple) GDO?S

author: edigi
author_rank: Regular Contributor
timestamp: August 18, 2019, 08:15:48 am
content: Quote from: StuartA on August 16, 2019, 06:51:58 pmWith a 2 port VNA you can get a lot more information in a lot less time than with GDO. NanoVNA is definitely for hobbyist, for professional use there are too many limiting factors like frequency range, dynamic range, usability and possibility to make documentation with it etc.I suspect that even the Siglent VNA mentioned earlier is bought mainly by hobbyist.

author: tautech
author_rank: Super Contributor
timestamp: August 18, 2019, 09:03:02 am
content: Quote from: edigi on August 18, 2019, 08:15:48 amOnly committed hobbyists with the budget but small business see the SVA as a cost effective tool for their RF needs.With a 3.2GHz model coming later this year there'll be more interest in these SVA models.

author: joeqsmith
author_rank: Super Contributor
timestamp: August 18, 2019, 02:33:49 pm
content: Quote from: tautech on August 18, 2019, 09:03:02 amHas any details been released that you can post for the 3.2GHz model? Will they offer some sort of evaluation period?

author: tautech
author_rank: Super Contributor
timestamp: August 18, 2019, 07:38:55 pm
content: Quote from: joeqsmith on August 18, 2019, 02:33:49 pmNothing official Joe however I'll share a little with you via PM.

author: erikka
author_rank: Regular Contributor
timestamp: August 20, 2019, 12:32:10 pm
content: the first measuring device I build. The association table between numbers on the dial, coil and frequency is not shown.Range 0.5MHz - 100MHzStill useful as signal generator, tunable power meter and to quickly check LC tuning

author: StuartA
author_rank: Regular Contributor
timestamp: August 25, 2019, 12:08:55 am
content: Quote from: joeqsmith on August 17, 2019, 07:00:47 pmRight, so the threadisabout grid dip meters, so surely, VNA's of any kind are off topic ?