Date   

Re: KC3EF Mobile Equipmemt

Jerry N9AVY
 

Rick:

Funny you should mention smoke detectors. Worked with smoke detectors for 40+ years and they can be quirky.  Most of the home units are ionization type (little radioactive sticker is indicative). They are cheap to produce, hence the mass use.  Problem is they are high impedance and very susceptible to RFI... like Hi-Z microphones. Verified that with an Engineer friend back then.  

The solution has always been to replace ionization smoke detectors with photo electric ones which have low impedance front ends.    Have solved a lot of RFI problems for hams that way.
Photoelectric detectors are a bit more expensive, but it's worth it.

Jerry  n9avy



On Thursday, April 22, 2021, 07:40:31 PM CDT, Rick - N7WE <n7we1980@...> wrote:


When doing the initial shakedown on my /P setup for the car (hamsticks on mag mount, center of the CRV roof) I tuned the hamsticks with a MFJ 259B.  But when I put 25W into it from the rig, I had enought RFI inside the car to cause the computer to go all wonky and the SWR up substantially.  Bought a Balun Designs Model 1110 - QRP 1:1 Isolation/Choke Balun 1-54 MHZ, SO-239 connectors in and out.  It was about $50 as I recall.  It is rated to 300W SSB even though it says QRP.  So it is easily good for 75W continous modes.  Put it in the coax about 12" from the base of the Mag Mount and RFI disappeared.  SWR also went back to the tuned level.  My conclusion...I had massive common mode on the coax without the isolation.  These are great little chokes for PSKers.  I used another on the EagleOne off the back of the motor home as motor homes have lots of circuits (like furnace blowers, smoke alarms, vent fans, etc.) that just love to suck up RFI and do strange things.  I'm told, but haven't verified, that common mode on the coax can mess with your radiation pattern too. Of course, YMMV but that was my experience.
Rick - N7WE
070 - #1602


Re: KC3EF EL39

Richard Rohrer
 

The wx looks good for tomorrow in EL59.  I will start on 20mtrs and if that does not work, I can put the 40mtr stick on and try that.   Bill if you send your phone number to my personal e-mail kc3ef at arrl.net I will text you when we are getting to the grid. 

73
Dick - KC3EF


Re: KC3EF Mobile Equipmemt

Rick - N7WE
 

When doing the initial shakedown on my /P setup for the car (hamsticks on mag mount, center of the CRV roof) I tuned the hamsticks with a MFJ 259B.  But when I put 25W into it from the rig, I had enought RFI inside the car to cause the computer to go all wonky and the SWR up substantially.  Bought a Balun Designs Model 1110 - QRP 1:1 Isolation/Choke Balun 1-54 MHZ, SO-239 connectors in and out.  It was about $50 as I recall.  It is rated to 300W SSB even though it says QRP.  So it is easily good for 75W continous modes.  Put it in the coax about 12" from the base of the Mag Mount and RFI disappeared.  SWR also went back to the tuned level.  My conclusion...I had massive common mode on the coax without the isolation.  These are great little chokes for PSKers.  I used another on the EagleOne off the back of the motor home as motor homes have lots of circuits (like furnace blowers, smoke alarms, vent fans, etc.) that just love to suck up RFI and do strange things.  I'm told, but haven't verified, that common mode on the coax can mess with your radiation pattern too. Of course, YMMV but that was my experience.
Rick - N7WE
070 - #1602


Re: KC3EF EL39

Richard Rohrer
 

Due to time constrants we are bypassing EL39. EL59 will depend on wx.  

Dick


Re: Mobile antenna placement and patterns

stan W9SMR
 

Wow, Peter!

That was a very comprehensive exercise. Well done and thanks for sharing it.

73,
Stan
W9SMR

________________________________________
From: main@070Club.groups.io <main@070Club.groups.io> on behalf of Peter, NN9K #2629 <nn9k.peter@gmail.com>
Sent: Thursday, April 22, 2021 10:25 AM
To: main@070Club.groups.io
Subject: [070Club] Mobile antenna placement and patterns

I just uploaded a file -- 2007_MARAC_Bakeoff_Results.pdf<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2F070club.groups.io%2Fg%2Fmain%2Ffiles%2F2007_MARAC_Bakeoff_Results.pdf&data=04%7C01%7C%7Ca9284d7b30d849fb277e08d9059a6e51%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637546983089346176%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=uSGr9DgRJUOWAJouk8yyabGHVABahDtHdMFXlMuz3II%3D&reserved=0> and although it is "old" data it is still relevant today. It was probably the most comprehensive mobile antenna testing I have seen and participated in. Take your time reading it and hopefully it will help you make informed mobile antenna decisions.

RF problems during mobile operation. The Icom 7000 was very prone to RF problems even to the point of shutting of shutting down the radio. A simple torrid choke on the antenna lead would solve the problem. And I suspect the newer Icoms may also be a bit sensitive to RF on the feedline also and possibly any device attached to the radio could be affected also.

One more comment -- mag-mounts need to be grounded! A separate ground strap from the mount to a good ground point on the vehicle will make a difference in SWR and radiation pattern. Use good heavy braid and if done carefully will help keep the mount in the vehicle during sudden stops.
--
Peter, NN9K


Mobile antenna placement and patterns

Peter, NN9K #2629
 

I just uploaded a file --  2007_MARAC_Bakeoff_Results.pdf and although it is "old" data it is still relevant today. It was probably the most comprehensive mobile antenna testing I have seen and participated in. Take your time reading it and hopefully it will help you make informed mobile antenna decisions.

RF problems during mobile operation. The Icom 7000 was very prone to RF problems even to the point of shutting of shutting down the radio. A simple torrid choke on the antenna lead would solve the problem. And I suspect the newer Icoms may also be a bit sensitive to RF on the feedline also and possibly any device attached to the radio could be affected also.

One more comment -- mag-mounts need to be grounded! A separate ground strap from the mount to a good ground point on the vehicle will make a difference in SWR and radiation pattern. Use good heavy braid and if done carefully will help keep the mount in the vehicle during sudden stops.
--
Peter, NN9K


Re: KC3EF EL39

Bill-N7RI
 

Thanks Dick

Bill
N7RI
070-1191


On Thu, Apr 22, 2021, 6:57 AM Richard Rohrer <kc3ef@...> wrote:
Will be in EL39 in afternoon.  Will let you know when getting near.  

Dick


Re: KC3EF EL39

Richard Rohrer
 

Will be in EL39 in afternoon.  Will let you know when getting near.  

Dick


Re: KC3EF EL39

Bill-N7RI
 

I definitely can use EL39 , and 59 depending on which way you are headed.
Bill
N7RI

On Wed, Apr 21, 2021 at 9:40 PM Richard Rohrer <kc3ef@...> wrote:
We will be in EL39 tomorrow if anyone still needs this grid.  Send me an email to kc3er at arrl.net.  Will probably be there in the afternoon.
--
Dick - KC3EF
070 - 747



--
Bill Fults
N7RI
PODXS 070-1170


KC3EF EL39

Richard Rohrer
 

We will be in EL39 tomorrow if anyone still needs this grid.  Send me an email to kc3er at arrl.net.  Will probably be there in the afternoon.
--
Dick - KC3EF
070 - 747


Re: KC3EF 4/20 After Action Report

Richard Rohrer
 

Hi Rick,

Kathy says thanks for your kind comments, but she still is not going to EL88, hi hi.  She think we should get together and spend the $100 and go to Dry Torguas.

73
Dick - KC3ER


Re: KC3EF Mobile Equipmemt

Richard Rohrer
 

Hi Bob, 

I found on this trip that I had more problems with RF in the computer than I have ever had.  Reduced the power to 50watts and that seemed to solve the problem.  When we return to MD I am going to experiment with the setup and see if I can find out a better solution.  Since running mobile I think with the less than optimum antenna the more power is better. 

From my experience I found that sometimes some small changes in cabling can cause problems. 

73
Dick - KC3EF 


Re: KC3EF 4/20 After Action Report

Richard Rohrer
 

Hi Steve,

To answer your questions: 

1.  The mount is on the left tail light of the mini-van. 
2.  The bottom quarter/third of the hamstick is near the van body.
3.  It sticks out to the side and some what of the back. 

I chose this method, since the van has sensors on the rear bumper which trigger if any thing is around the back of the vehicle.  I had previous experience with having a ham stick mounted on a mag mount and it was fine until the xyl hit 70 mph and it flew off the back of the vehicle.  

Kathy, my xyl, has often wondered if position of the van would improve propagation in a specific direction.  She thinks that doing the experiment you proposed would be great to do.  She is a post masters nurse and computer person, so this seems like a neat idea to her.  We are going to be in South Carolina next month and could drive around the island and send test transmissions.  We will be in Tennessee in June and could do the same thing.  In July we will be in Maryland for work and could also do the same type of experiment.  It would be interesting to get several 070 members to participate and see what happens.  

73
Dick - KC3EF


Re: KC3EF Mobile Equipmemt

Bob Motyl KK6KMU
 

Dick,
Thanks for replying.  I just got a new laptop with similar specs.  Still working out the bugs.  I think I'm still getting RF to interfere with the computer.  Going to try different USB cable and some ferrite beads.  I use my ICOM IC7200. a hamstick antenna and a 30 AMP-HR battery.  Going to get a solar panel eventually to charge the battery.

Thanks again,
Bob KK6KMU


Re: KC3EF Mobile Equipmemt

Richard Rohrer
 

Hi Steve,

That is a good suggestion, but our mini-van has a built-in 120vac inverter.  The xyl says I am too lazy to crawl in the back and hook up my power supply for the computer.  I guess she is right, hi hi. 

73
Dick - KC3EF


Re: KC3EF 4/20 After Action Report

 

It might also be interesting to add a 2nd Ham Stick off the front, and phase them. They'd "fire" broadside, And I'd be pleased to donate a 20m stick and the harness if you'd like to try, John.
The harness would be 1/4 wavelength, X the velocity factor of the RG-6 phasing coax.
I've done that before, and the +++ was that it improved my receive a few db.'s. Receive is based almost entirely on resonant capture area.
Milt.
N6MG
070-650

-----Original Message-----
From: Steve W3HF <w3hf@...>
To: main@070Club.groups.io
Sent: Wed, Apr 21, 2021 10:09 am
Subject: Re: [070Club] KC3EF 4/20 After Action Report

Thinking about this and Dick's description of his setup (hamstick on a tail light mount), I have a few questions and a speculation:

- What does the tail light mount look like? I presume it's a bracket that sticks out between the tail light lens and the metal body of the car.
- Which direction does it stick out--to the back or to the side?
- Which tail light is it on?
- How much of the hamstick extends above the top of the T&C minivan? (Or what fraction of it is below the roof line?)

I wonder if part of this could be the direction the car is pointing and thus the location/orientation of the ground plane, which is affected by the answers to the questions above. It might be an interesting experiment some time to find a large empty parking lot and ask Kathy to drive around the perimeter so that the car ends up rotating 360 degrees (multiple times). If we had multiple stations listening, all in different directions, we might be able to get an idea of the pattern the antenna-on-car generates.

And if someone is good with antenna modeling software, we could compare the experimental pattern with an analytical prediction.

Steve
W3HF


Re: KC3EF 4/20 After Action Report

Jerry N9AVY
 

My 2 cents worth ...

Not an ideal spot to mount HF antenna. Years ago I had a minivan and mounted antenna on left rear quarter panel about half ways up. It did okay mostly. Any higher and I hit overhead wires which were sometimes too low or low overpasses. Everything worked pretty well until I got new van and mounted the High Sierra HF-1500 a bit lower... some impatient person passed me on left trying to get into left turn lane. Driving a big, black muscle car (her boyfriend's) she had a nice white stripe from front to back. Sure she heard about it from BF.  The high Sierra was destroyed and before I could get replacement parts High Sierra went belly up.  (Deductible was more than parts !)

Eventually went with 3 magnet mount on roof with ham stiks which worked fine except on 40/80m (wind loading problems pulled antenna off - and mag mount).  This worked okay until I worked for a company with said "NO" to ham radio. Was SSB back in those days and enjoyed whizzing alone highway yakking with hams in Europe & Australia.

A ham stik mounted in center of van roof is what works and gives best radiation pattern, but clearance to tip has to be less than 13" 6" otherwise you'll have problems with overpasses and drive up windows. Yes, I lost a few Ham Stiks to drive up windows because I was too lazy to get out a walk !

Am sure there is info somewhere on net about mobile antenna installs, but one needs to hunt for it.

Jerry N9AVY


On Wednesday, April 21, 2021, 12:09:22 PM CDT, Steve W3HF <w3hf@...> wrote:


Thinking about this and Dick's description of his setup (hamstick on a tail light mount), I have a few questions and a speculation:

- What does the tail light mount look like? I presume it's a bracket that sticks out between the tail light lens and the metal body of the car.
- Which direction does it stick out--to the back or to the side?
- Which tail light is it on?
- How much of the hamstick extends above the top of the T&C minivan? (Or what fraction of it is below the roof line?)

I wonder if part of this could be the direction the car is pointing and thus the location/orientation of the ground plane, which is affected by the answers to the questions above. It might be an interesting experiment some time to find a large empty parking lot and ask Kathy to drive around the perimeter so that the car ends up rotating 360 degrees (multiple times). If we had multiple stations listening, all in different directions, we might be able to get an idea of the pattern the antenna-on-car generates.

And if someone is good with antenna modeling software, we could compare the experimental pattern with an analytical prediction.

Steve
W3HF


Re: KC3EF 4/20 After Action Report

Steve W3HF
 

Thinking about this and Dick's description of his setup (hamstick on a tail light mount), I have a few questions and a speculation:

- What does the tail light mount look like? I presume it's a bracket that sticks out between the tail light lens and the metal body of the car.
- Which direction does it stick out--to the back or to the side?
- Which tail light is it on?
- How much of the hamstick extends above the top of the T&C minivan? (Or what fraction of it is below the roof line?)

I wonder if part of this could be the direction the car is pointing and thus the location/orientation of the ground plane, which is affected by the answers to the questions above. It might be an interesting experiment some time to find a large empty parking lot and ask Kathy to drive around the perimeter so that the car ends up rotating 360 degrees (multiple times). If we had multiple stations listening, all in different directions, we might be able to get an idea of the pattern the antenna-on-car generates.

And if someone is good with antenna modeling software, we could compare the experimental pattern with an analytical prediction.

Steve
W3HF


RC3 Standings

Jim K5SP
 

The RC3 Leaderboard and Top Ten pages of the website have been updated to reflect the standings through the 31 Flavors Contest.

Good job to all!

73

Jim K5SP


--
Jim,  K5SP #483
Executive Director/Member Services Director


Re: KC3EF 4/20 After Action Report

Rick - N7WE
 

Well prop was WEIRD yesterday to say the least!  At times Dick you were S9+ with 100% copy on this end - yet you couldn't hear me.  At other times, you would suddenly disappear off the waterfall.  I've never operated HF mobile, but from operating HF portable I have to wonder if local terrain plays a major role.  I know when portable I have been in places where I was getting out (feedback via internet), but was receiving nothing.  And that was with a 24' EagleOne off the back of the motorhome.  

Thanks so much for doing all these road trips and grids.  And for your perserverence despite tough conditions.  Special thanks to Kathy too!  If she didn't do the route plan and the driving, this would not be possible!

I'll be looking for you in EL59.  If we make it, it will finish LA for me.
--
Rick - N7WE
070 - #1602

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