RFI from Ham Radio Causes Shades to Activate

[RubiconTrail]

Galvanized should work as well as stainless, as long as it is thick enough to maintain integrity. The only advantage of stainless is that it tends to corrode less in the presence of dissimilar metals. I made the plate in my shop, just put it in the shear and then used a strippit fabricator to punch the hole. I know, not everyone...Any countertop shop that does sheet metal should be able to produce one for you or I can punch one out for you if you're ever nearby. I have no plans for the east int he near future, but will be in Southern California and Arizona this winter as well as Moab in the Spring.

tTurns out he K-99 is hard to come by. Hardened coax assembly made for the military in the 80's with a durable connection at the NMO base and extra shielding because they were just starting to commonly use microwave frequencies and were dealing with RF leakage. I have some new old ones and didn't realize they were unavailable until I tried to find them.

So the most durable and RF leak free NMO connector you can find. I hear Laird makes good ones.

https://www.solidsignal.com/pview.asp?p=nmohpcg518

[NXR]

Originally Posted by nagias

I recently decided to run a few cables from the rooftop into the front windshield driver side cabinet through the vertical aft of the front end cap. Cables included were for a couple of Weboost Antennas and a RG59 cable for a 2m Ham radio.

The installation went fine except for the scary surprise that when the transmit button is pressed on our Yaesu FT2980R, the front day shades activate and start closing. I can avoid the shades from activating if the transmit power is set to the low.

Besides rerouting the cable a different way, any suggestions on what can be done to avoid the shades from activating?

RG59 is 75 ohm cable for TVs. Did you use RG59 or did you mean to write RG58?

Ray

[NXR]

Originally Posted by Gary.Jones

Good luck with it. Verticals are a bear to have installed correctly in a motorcoach because while it is easy to mount an antenna on the roof, the roof has little significant metal to act as the ground plane in close proximity to the base of the antenna..

Yup, this is why I was looking at the COMPACtenna instead. Only 7" tall for the 2M/440 version and no real ground plane required, just some metal below it. Installing it in the middle of a flat metal roof makes it perform poorly. Installing it on the car cowling (or on a motorhome ladder) works much better.

The comparative reports from people that have actually used it say there is no real difference with a full-sized 2M/440 vertical.

The fellow who invented it lives the next city over and I've talked with him about using it on a motorhome. He's certain ti will work fine. I even bought the cable to run from the top of the ladder to the driver's compartment at Dayton/Xenia.

Since there doesn't seem to be a lot of .52 activity while traveling I decided to go a different route instead and installed a Yaesu Fusion Wires-X node in a motorhome compartment. The radio is an FTM-100D cranked down to 1 watt on low power to a 90-degree SO239-to-female BNC to a 2M/440 HT whip. The PC is a PiPo X8S, about $110. It connects to the Internet Wires-X network using the hotspot I already had installed.

So now I just use the FT2DR HT and can literally "talk to the world". Or just my buddies, which is more the reality of it.

Except for the PiPo and a small 12 VDC power supply I already had the equipment in the house; I just moved it to the motorhome in the driveway.

Ray

[nagias]

Originally Posted by NXR

RG59 is 75 ohm cable for TVs. Did you use RG59 or did you mean to write RG58?

Ray

Indeed, the mount uses RG58 cabling and I misstated earlier. Thanks for catching that.


Ray, thanks for describing your setup. It appears to be well adapted for a mobile/RVing scenario.

[NXR]

Originally Posted by nagias

Indeed, the mount uses RG58 cabling and I misstated earlier. Thanks for catching that.

Too bad. That would have been an easy fix.

Ray

[nagias]

Thanks John for the additional info and recommendations for an alternate mount.

Update:
As the weather has dried out the issue has returned, so at least it is reproducible.
The ferrite chokes from Amazon, wrapped around the shade wiring and antenna cable did not help. They do not describe the type of material used but they were the quickest to get and with the free returns, the easiest to evaluate.

Any suggestions on what might be a better choke to try out?

[FreshAir]

RG-59 and RG-6 are 75 Ohm coax cables designed for cable television but because they have wide frequency response and low line loss with an impedance of 75 ohms they are commonly used in Ham Radio applications using a standard 50 Ohm amateur radio antenna system. There may be a little impedance mismatch on the 50 Ohm antenna to about 1.5:1 SWR. Still within the 2.1 SWR recommended limit. An antenna tuner can help.

50 Ohm RG-58 or RG8 is the best cable to use but is more expensive.
Ham operators like to save a buck when they can.

The grounding, like mentioned, is very important. Also the 2 meter band at a 38" 1/2 wave length requires keeping cable run lengths to multiples of 38". As I recall the OP's SWR is perfect at 1:1 so grounding and cable length is not suspect. FWIW.

pat

[Mark_K5LXP]

Originally Posted by RubiconTrail

So the most durable and RF leak free NMO connector you can find. I hear Laird makes good ones.

While it can't hurt to use premium mounts, in this application it won't really make a difference. The antenna is mounted to a largely RF transparent surface and no amount of shielding of the coax center conductor is going to decrease the common mode present. The preponderance of incident RF is from the antenna, and the installation is promoting CM current on the feedline.

Mark B.
Albuquerque, NM

[Mark_K5LXP]

Originally Posted by nagias

Any suggestions on what might be a better choke to try out?

Did you do the sweep/survey to see what frequencies and power levels the problem appears? Without knowing that you're shooting in the dark. The ferrites you tried might be having a positive effect already but without a baseline to compare to you won't know it. Sometimes you get lucky shotgunning the solution but you can go through a lot of time and ferrites before you hit the magic spot, if you do at all.

Mark B.
Albuquerque, NM

[nagias]

Originally Posted by FreshAir

The grounding, like mentioned, is very important. Also the 2 meter band at a 38" 1/2 wave length requires keeping cable run lengths to multiples of 38". As I recall the OP's SWR is perfect at 1:1 so grounding and cable length is not suspect. FWIW.

pat

Pat,
I am still waiting for my SWR meter to arrive so have not been able to test my setup yet. John mentioned that his setup yielded a SWR of 1:1.

[nagias]

Originally Posted by Mark_K5LXP

Did you do the sweep/survey to see what frequencies and power levels the problem appears? Without knowing that you're shooting in the dark. The ferrites you tried might be having a positive effect already but without a baseline to compare to you won't know it. Sometimes you get lucky shotgunning the solution but you can go through a lot of time and ferrites before you hit the magic spot, if you do at all.

Mark B.
Albuquerque, NM

Mark,
I checked simplex frequencies as they are of primary interest to me. No interference occurs at the lowest radio power setting across the entire range. Interference is observed at the high power setting across the entire range. At intermediate power settings, more interference appeared to occur at the higher end of the range (>146.5). So far, I have only tested a couple of frequencies (146.45 and 146.50) with the chokes and there was no apparent difference with and without the chokes.