The Accidental Engineer

sometimes informative, sometimes funny, always interesting

Filter Mounting Options

In a rush to specify the proper filter for a particular task, an Electrical Engineer may not give much thought to “how am I going to mount this thing”?  Luckily for this Electrical Engineer (or more accurately, the Mechanical Engineer tasked with fitting all of the components into an enclosure) there are many mounting options available.  In this post, I’ll detail a few choices for mounting a simple rectangular shaped filter with connectors.  For the purpose of this discussion, I’ll assume that space is at a premium.


Tapped Holes:  By far, the most common way to mount a filter is by way of tapped holes on the bottom.  There would typically be one hole in each corner using an appropriately sized thread adequately spaced from the corners.  Some factors to think about are the overall size of the filter housing and the tap size – you would not want a tap size so large that the area around the hole would be thin and weak or with so little depth offering only 2 or 3 threads for the screw to attach.  Generally speaking, there is a size from 0-80 thru 6-32 that will provide the best combination of holding power and structural integrity.


Thru-Holes:  For applications where access to the filter’s bottom is not available, a thru-hole is the best option.  Typically, these would be in the corners of the filter and offer a “clearance hole” for the customer’s fastener.  As with tapped holes, thought should be given to select the appropriate fastener size.


Flanges or Plates:  A slight twist to thru-holes, flanges or plates offer the user the ability to use a fastener of any size to mount the filter.  The attachment points are more or less independent of the filter and reside outside of the filter housing.  Typically these options are used when there is an existing grid mounting matrix in the systems chassis and the user would like to take advantage of that grid.


While I only explored the 3 most popular options, many more are available.  If you are interested in a more substantial discussion of filter mounting options, feel free to contact me directly by email at


At Reactel, we manufacture RF & Microwave Filters, Multiplexers and Multifunction Assemblies with satisfied customers across the globe.  If you would like to explore a filter for your requirement, please visit or email me directly at


WAMI delayed is not WAMI denied

I was sorry to see the announcement that WAMICON 2020 had been canceled – sorry….. combined with WAMICON 2021.  According to the Conference organizers, “…the WAMICON 2020 Conference will be combined with WAMICON 2021.  The Conference will remain in the same location (Clearwater Beach, FL), with the new dates in March/April 2021 to be announced later.  Papers accepted in WAMICON 2020 will be presented alongside WAMICON 2021 papers.”


While you may not have heard about WAMI, it is a fabulous, well run, smaller Conference held in Florida each year.  WAMI stands for Wireless and Microwave Information and was born from the University of South Florida’s WAMI Center that was founded in 1997.  In addition to a top-flight Technical Program and the 20 or so exhibitors, WAMI’s real gem is relationship building among those in attendance.  To borrow a phrase from Dr. Larry Dunleavy, the relationships or “WAMI magic” is a significant reason this small show has such a loyal following.  WAMI is one of my favorite Conferences in our industry.


Typically held in April, WAMI fell victim to the ongoing COVID pandemic and a decision was made in February to move the Conference to a December date.  Those of us on the Steering Committee were hoping that the global situation would be back to “normal” by then and the Conference could proceed, albeit it delayed.  Regrettably, that was not the case, and the decision was made to push forward with plans for 2021.


I encourage you to visit the WAMI website ( to see what the buzz is all about, and I look forward to seeing you there in 2021.

How wide can you go?

We often get asked about how wide a filter’s bandwidth can be made.  Typical filter technologies are limited to approximately 75% BW or so.  For applications where ultra-wide, multi-octave bandwidths are required, you would need more than an ordinary filter.  The best filter choice for bandwidths in the 150% range would be a design utilizing Suspended Substrate Technology (SST).


SST is a printed board topology that utilizes a double-sided printed board between two ground planes with air dielectric traces that mirror the circuit printed on the board.  Ultra-wide responses are realized by combining highpass and lowpass circuits to create filters and multiplexers.


Using SST, achieving passbands from 2 to 18 GHz or 18 to 40 GHz and beyond are entirely possible.  If you have ultra-wide bandwidth requirements, please contact us, and we will show you how well SST will work for you.

Review of the Virtual IMS (vIMS)

Some contemplative reactions to the Virtual IMS from an Exhibitor – the comments are my own and may not be indicative of other’s experience or their impression of the vIMS.   The live portion of the Virtual IMS concluded on August 6th though much of the Conference is available On-Demand thru September 30th.  I encourage you to visit the Conference website (


If I had to rate my experience with the vIMS on a scale of 1 thru 5, I’d give it a 1.  I was underwhelmed by the interface as I noted in my earlier blog post, and the “traffic” through my booth was minimal at best.  Once I subtracted out the industry friends who swung past for a look, the numbers were quite dismal.  All told, the show regrettably met my low expectations.


Despite the poor experience I had, I am happy that I gave it a shot.  There was little to lose and very much to gain.  I enjoy being a “charter member” or “early adopter” for events in our industry and this was no different.


Looking back, I liken the vIMS to the first time IMS went to Hawaii in 2007.  Honolulu was presented as a unique way to engage with markets that were often out of reach.  Despite initial reservations – cost of travel chief among them – I decided to exhibit.  Of course, expectations (built by the pre-show hype) did not come close to reality.  However, if I am to be a supporter (some might say steward) of the industry, I feel like I have to try a variety of things.  I wised up when IMS made its inexplicable return to Honolulu again in 2017 dialing back both expectations and level of involvement as an exhibitor.  Should IMS2021 in Atlanta need to become a vIMS, the sell to the exhibitors will be much harder.  I will certainly look more critically at the idea of participating again.


Lots of negative in this post, time for some positive.  A huge amount of thanks goes to Tim Lee, General Chair IMS2020 – I know he and his large team of volunteers worked extremely hard on the original IMS2020.  Tim was looking forward to the opportunity for the industry to see what LA could offer in its return to his city for the first time since 1981.  To quickly pivot from an in-person show to a virtual one took a tremendous amount of effort in a very short amount of time.  Thanks, too, go to Lee Wood and his team at MP Associates.  Their calm and reasonable handling of 600 exhibitors belies the chaos that surrounded them.  It was certainly an “interesting” way for MP to exit as the Conference’s Exhibit and Events Manager.  I am saddened that I was not able to thank them in person for their 12 years of handling our industries showcase event.  I’ll have more on the MP exit and Horizon House entrance in a later posting.


In the meantime, stay safe and wash those hands!

Thoughts on the Virtual IMS (vIMS)

As most of you know by now, IMS2020 that was to be held in Los Angeles last month was cancelled as an in-person event and rescheduled as a virtual event for August 4-6.  Exhibitors who were involved with the in-person exhibition were offered the opportunity to participate in the vIMS.  As of this writing, it looks like approximately 200 companies took IEEE up on this offer, and Reactel is one of them.


I have been in RF & Microwave for about 35 years and while a vIMS is certainly something never tried before, I do not recall any Exhibition of this magnitude in our industry as a virtual-only event.  To pull it off seemingly on the fly, with an extremely short time-line will be nothing short of miraculous.  No matter how it turns out, General Chair Tim Lee, the folks at MP Associates and GTR deserve many thanks for making this possible.


Despite the monumental planning and forethought given, nothing can be a “drop-in” replacement for an in-person IMS.  It is just an impossible task.  I have high hopes for a successful show – but I am a little skeptical because that is my nature.  Having gone partially through the process of setting up our virtual booth, I am left feeling a bit underwhelmed.  I envisioned a more “virtual” experience with perhaps a floor plan and the ability to mouse over different booths for a preview of what might be inside and clicking to enter if it interested me.  What it looks like is more of an alphabetical directory of companies with keywords.  The list is searchable, which is nice, but again, I am underwhelmed.


I have been told many times that “you get out what you put in” and that is 100% true.  However, we do not have glitzy multimedia videos to upload in order to jazz up our virtual booth.  The hours of the exhibition look to be a challenge as well.  Reactel and many smaller companies may struggle to “staff” the booth for 36 hours across 3 days so that we can be there when an interested attendee clicks through.  At the moment, we seem better suited for an in-person show but are excited to see what the vIMS has in store for us in a couple of weeks.


I’ll have another post after the event to compare the reality with the expectations.

Connectors & Power

A recent customer asked about connector options for a filter we were building.  Reactel can use most any connector a customer needs on the filters and multiplexers we build.  Generally speaking, however, the choices become a little more limited when operating at high power levels.  This brief discussion will assume a quality built connector from a reputable manufacturer.  Using extremely low cost connectors of questionable quality will lead to inconsistent results.

A general rule of thumb would be as follows:

  • Up to 100 W: K, SMA, TNC, Type N, HN, 7-16 DIN
  • Up to 500 W: TNC, Type N, HN, 7-16 DIN
  • Up to 1 kW: Type N, HN, 7-16 DIN
  • In excess of 1 kW: HN, 7-16 DIN

A simple explanation of what would cause a connector failure at power involves the inability to handle elevated current levels and dissipation of the heat generated by that current.  There are other factors including frequency, altitude, heat-sinking and materials used that are a little too involved for this post.  Feel free to contact us with any questions you might have.

Why are there so many filter companies in Maryland?

This is a question I hear often on my travels.  What is it about Maryland that attracts the greatest concentration of filter knowledge?  Blue Crabs, the fabulous Eastern Shore, Fishers popcorn, Dolle’s Salt Water Taffy?  A 2011 article in Microwave Journal investigated this subject, and the answer is not as complex as you might think.  Give it a read; Made in Maryland: Filter Lore from Gaithersburg to the Eastern Shore.  Reactel is proud to be a part of Maryland’s filter legacy for the past 41 years.  Please contact us with your questions or requirements.

First Blog Entry – a blog post about blog posts

Hi, I’m Jim Assurian, Business Development Engineer at Reactel, Incorporated.  I have been with Reactel as an Engineer since 1991 and before that I held a variety of manufacturing positions here.  My hopes are that this space will be informative and somewhat interesting – at least as interesting as Filters, Multiplexers and Multifunction Assemblies allows me to be.

I will cover a variety of topics, not necessarily all of them technical though they will certainly lean in that direction.  During the course of my day, should an interesting topic come to mind, I’ll likely end up writing about it.  However, what is interesting to me may not be interesting to you, so feel free to ask me to discuss a particular item or issue.  My primary goal is to educate you about the challenges of filter design and open a dialogue about this backbone of communication systems.

Lastly, it should be stressed that these opinions are my own and do not necessarily reflect the views of Reactel, Incorporated.  Feel free to reach out to me –