Nelson Antennas 40-10 HF COMMON MODE RF CHOKE. HIGH CHOKING IMPEDANCE TEST SPECS

Description

Nelson Antennas
40m-10m
HF COMMON MODE RF Choke
This RF Choke made by Nelson Antennas (KD8UJM), Nelson_Antennas is one of ebays most successful antenna companies with nothing but rave reviews for the last decade. We highly encourage anyone interested in or needing an RF Choke to read this entire listing whether you end up purchasing our product or another product somewhere else. We feel there are too  many run-of-the-mill cheaply made chokes that do not provide the properly needed information in selecting any RF Choke. This is because testing is not done by many who claim their choke will do wonders across all HF bands. It is very possible for run-of-the-mill chokes to be very ineffective at certain frequencies and also a very common problem with run-of-the-mill chokes is that under certain conditions, they can even amplify RF issues significantly by becoming resonant. Nelson Antennas RF Chokes will NOT become resonant. This RF Choke is not a cheaply made unit made with ferrite beads, but rather a large and properly selected toroidal core/s for a combination of power handling and to do exactly what we intend our RF Choke to do.
When selecting a choke, such as these (no matter who you buy from), you must have a few basic questions answered. The first question you need to ask yourself is, are you looking for a general HF choke or are you having RF issues on one or two bands, because if there is an issue on one or two bands you can select a choke that primarily focuses a high choking impedance with only a resistive component (so the choke does not resonate) or amplify the issues. So it is very important that you know what the choking impedance is on every band and whether or not that choking impedance is resistive or reactive.
This RF Choke is what we consider the best 40-10m coverage choke because the choking impedance is purely resistive from 5.6MHz through 29.2MHz.
Choking Impedance as follows: (Rounded)
1.8MHz to 5MHz =  1k ohms
5.6MHz to 29.2MHz=2k-2.2k ohms (**pure resistive**)
This chokes impedance is purely resistive from 5.6 MHz - 29.2MHz! In other words, we challenge you to find a better choke with such a wide resistive reactance. This means the choke will have no chance of becoming part of the problem or even amplifying it.
Power handling capability is 1kw PEP from 160 meters through 10 meters.
MUST READ INSTALLATION DIRECTIONS BELOW
For end fed antenna installations:
End fed antennas almost always need to use the shield of the coaxial cable as a counter poise, so improper placement of an RF Choke will not lead you to the desired result. For any end fed antenna installation of a choke needs to be place in line right before your coax enters the building. In other words, with end fed antennas you almost always want the choke on your coax as far away from the antenna itself to allow the shield of the coax to be used as a counter poise effectively, this is very important with end fed antennas.
Standard Dipole antenna installation:
With standard dipoles or off center dipoles, sometimes we like a small section of our coax to radiate as part of the antenna, because that can allow us some vertical polarization as well. If that is the case for you, install the choke inline at the point which you would like your coax to stop radiating. If you do not wish any of your coax to radiate or be part of your antenna you should install this choke in line as close to your antennas feed point as possible.
This choke is 3.5 inches in diameter and approximately 3.25 inches long, not including SO-239 connectors and weighs just over 12 ounces.
The very high quality SO-239 connectors are fully sealed as is the housing.
Nelson Antennas has also designed and tested 2 additional chokes, I will be the only distributor of and I will be listing them soon.
To give customers a more customizable choke to their needs, this choke will be more specialized towards great specifications from 40m-10m and I also have a 2nd choke listed with high specifications for 160m-10m, pure resistive from 5.5 through 26.5MHz.  That choke is eBay item number
264946030545
A VERY DETAILED RECENT CUSTOMER FEEDBACK OF WHAT A WELL DESIGNED CHOKE CAN DO IN THE RIGHT CIRCUMSTANCE
Sent:
Mar-25-21 08:59
Hello: I feed six different HF transceivers thru a six position coax switch in to my Kenwood TL-922 HF Amp. Was having a problem with just one of the transceivers, a TS-430S was not getting full out-put on TL-922 & Amp was arcing on 20-meters with TS-430S. SWR between TS-430S and TL-922 was fine less than 1.5 to 1. figured problem was some kind of common mode issue between Xcvr & Amp. Did a search on E-bay for a choke and came across your product. I liked what I read and ordered your choke. I installed your RF choke between my coax switch & input to TL-922 amp. Like magic!! TS-430 drove TL-922 amp to full out-put & no more arcing in amp tank circuit. Your product solved my problem hands down !!!. You might let other Hams know about this. your choke solves other types of common mode issues. as in my case interfacing of rig & amp. Common mode issues do occur in the Shack. I will be ordering another choke from you next month.
PS: I do believe my receive might be a little quieter. Have the same gain but I seem to hear the weaker signals a bit better after installing your choke. I will evaluate this further, more than likely the local man-made noise was being picked up by the coax shield & now is being attenuated by your RF choke. common mode noise on coax shield being removed. another great feature of your choke.
73's again Dave
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