开云体育

We use blocks covered with static dissipative film (Amstat, etc.) The surface resistance is sufficiently high that it doesn't load the RF system, but it also prevents the charge that inevitably

Large styrofoam blocks are the "standard" in professional communities. At home, with all the RF test equipment, I use either corrugated boxes or an empty 50-gallon rubbish can. I could buy large

Corrugation should lower the dielectric constant and loss of any material roughly in proportion to its air content. So corrugated cardboard should have better specs than the uncorrugated cardboard

One can easily MEASURE the εr of the corrugated box material. Build a parallel plate capacitor using aluminum foil, single or double-sided FR-4 PCB, or some other creative set of flat conductors.

Possibly the εr rating of the corrugated paper, itself, is well above unity, which I seriously doubt. But a large box is pretty much all air with an εr miniscually larger than unity. Dave - W?LEV

I used to use cardboard to support things until I found these 1 MHz specs for cardboard with a density 0.5 ounces per cubic inch: dielectric constant 6, loss tangent 0.04. By contrast, styrofoam type

When I worked on GPS initial design we had a rigorous spec for the noise temperature of several of the receivers. This was in the late 1970's. We could not make the spec with anything from the US at

I was just speaking with a fellow who does such work and, unsurprisingly, his first question to me was "How many initially and per year and what is the budget?". It might wind up cheaper renting a

Dry discarded corrogated shipping boxes also work well. Dave - W?LEV wrote: -- Dave - W?LEV

The Buy American Act probably falls in the exception: "the items to be procured or the materials from which they are manufactured must be present in the United States in sufficient and reasonably

Order from R&L Electronics: * https://www2.randl.com/* No connection other than ordered quite a number of Chinese electronics including the NANOVNAs and TinySAs / Ultra. My credit card issued on my CU

I placed a lot of orders on AliExpress over several years, including the NanoVNA, TinySA, etc. Most of the time it worked fine. Until recently! AliExpress sent my last three orders through a little

I have found that blocks of Styrofoam are excellent for this use; polystyrene is a pretty good dielectric and the foam is 99% air so even better. 73, Don N2VGU

hi Daniel, maybe this can help: https://nanovna.com/?page_id=121 best 73 de i2NDT Claudio

Hi Arun, I can vouch for Mini Circuits transformers. I had Mini Circuits build some custom 100 Ohm balanced hybrid splitters for a VDSL broadband startup project in Australia. We used 100 Ohm Cat5

Hello Mark, I do not pretend to be an expert here, but I will make a few observations. 1. Many posts in this group have already noted that connecting a NanoVNA to a computer via USB cable results in

Echoing what Dave posted, I agree it would be best to physically locate Nano VNA at the antenna feed point. This could be physically dangerous or impossible. And how to view or save the measurement? I

Unbalanced antenna should have sufficiently large ground plane to minimize impact of transmission line. Objects near the antenna can change characteristics of the antenna. Such as people and things in

Yeah, indeed... so onto question 2... anybody in the US want to build one that can be sold to federal agencies or federal contractors? It involves some paperwork if haven't built for them before.

Highly unlikely. Are there any US manufacturers building anything in the way of "consumer" electronics?