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March 2010 Archives

 

21 March 2010

I have a new "sort of" kit. Last year, I designed a 3-dB hybrid coupler, the Z10050A, to be used to split a signal into two paths (to connect two receivers to one antenna, for example) or to combine two signals into one (two signal generators combined for intermodulation testing, most commonly). The Z10050A consisted of a small printed circuit board, parts, three BNC connectors and a 2"x2"x1" case.

I decided not to make the Z10050A a full kit because it's too labor intensive for me, particularly if bought assembled.

There's still interest in an inexpensive 3-dB hybrid coupler, and I've recently sold a few "parts only" kits. These include all the electronic parts needed to make the coupler. The builder is responsible for an enclosure and three connectors of choice.

The kit does not include a printed circuit board because it's simple enough not to need one and in fact the coupler has a bit better port-to-port isolation when built with the parts hanging in air.

I've written an 8-page "Notes on Building the Z10050A" manual for the parts kit, with illustrations on how to build a coupler with the parts, as well as measurements on a sample coupler. Click here to read the manual. The Z10050A is quite a decent performer, as good as a similar Mini-Circuits coupler in my measurements.

The Z10050A  parts kit is $5.00 for one, $9.00 for two. This price includes postage within the USA. DX prices are $6.00 for one, $10.00 for two, which includes first class (air) postage.

There's a separate page for the Z10050A at Z10050A 3 dB Hybrid
 

21 March 2010

Last September, Bob, K7HBG, loaned me an AADE L/C IIB inductance and capacitance meter to review. After making a few measurements of standard inductors and capacitors, it was apparent that the meter failed to meet the specified standards.

I returned the L/C IIB to Bob, along with a summary of my findings and he sent the meter to AADE for repair and recalibration. (Bob had one of the first L/C IIB meters, purchased some 15 years ago, and it had not been calibrated since purchase.)

I've now had a second pass at the L/C IIB meter and have written a detailed review of it, available by clicking here. (This is a 1.5 MB PDF file.) I've also added a short page for the meter AADE L/C IIB Meter Review but it is just a placeholder for the PDF file.

If you don't care to read the full review, my conclusion is that it is a useful instrument for builders and generally meets its quoted performance standards. It has several limitations and a knowledge of those limits will aid the user in interpreting measurement results. Considering the price (kit is around $100, assembled is $ 130) it's a good performer.

 

16 March 2010

I've added a new web page Accuracy of W7ZOI AD8307-based Power Meter which links to a detailed analysis and calibration I did recently of a power meter build by Gary, W2GNN, from  the June 2001 QST article by Wes Hayward, W7ZOI and Bob Larkin, W7PUA.

 

15 March 2010

I've been remiss in not updating the web site for 11 days. I have several interesting documents to post but have not had enough time to do so yet.

I have made a small revision to the Z10040B construction and operating manual, available by clicking here.

 

04 March 2010

I found an error in my paper on intermodulation performance of the Z1501D active antenna. The error is at page 17 and I over-stated the predicted strength of the 3rd order intermodulation signal produced by two -20 dBm signals. The unwanted interfering signal (in "S-units) is not S-5 as I originally said, but S-0 and hence below the noise level in all but the exceptionally low noise locations.

Although I computed the interference level in dBm correctly, I mis-read my spread sheet conversion from dBm to S-units. The spread sheet is in both dBm and dBW and I looked at the dBW column when originally drafting the analysis.

A corrected version of the analysis now replaces the original document.
 

02 March 2010

All outstanding orders for Z1501D active antenna, Z1203A coupler are completed and shipped.

The photo below shows five Z1203A couplers on my bench ready for assembly Saturday morning, completed late Sunday.
 

02 March 2010

As usual, last month's Updates are now in the archive. You may view the February 2010 updates by clicking here or by the links in the  table at the top of this page.