Elecraft

Really OT: Inside-the-vehicle HF antennas (possible bonus points)

Classic

List

Threaded

23 messages Options

wayne burdick

Really OT: Inside-the-vehicle HF antennas (possible bonus points)

Administrator

I’m dealing with one of the last unsolved problems in amateur radio: how to operate HF mobile without an antenna. At least not one that, according to some vehicle co-owners/spouses, would defile your new sedan.

For 10 bonus points that have only philosophical value, your challenge is to create an invisible mobile antenna and actually make a QSO on it. For practical purposes (i.e., not frying the car or passengers) let’s say the maximum power level is 10 watts. The bands of interest are 40-10 meters.

Here are some ideas I’m considering:

- mag loop in the rear window
- thin wire loop on a roof rack
- gamma match to the entire roof
- surface acoustic waves
- prayer

Other ideas?

Yes, I know this violates the laws of physics and bioethics. And I fully expect the car to generate debilitating levels of RFI. But isn’t this the least you’d expect from an unsolved problem?

Thanks in advance,

Wayne
N6KR

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

k4vd

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

Have you considered an isotropic antenna? I understand it is an ideal
antenna that radiates in all directions and has no physical form. Sounds
like the perfect stealth antenna to me. I've seen them advertised in the
back of True Detective magazines alongside the x-ray glasses.

I was thinking a towed array like a submarine uses. They are pretty
stealthy but you might need to register them separately as a towed vehicle.

Wait - that's an idea. Trailer hitch and set up a trailer as a mobile
antenna farm.

73,
Kev K4VD

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

k6mkf

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

You may want to have some minimum distance required for the QSO. Two KC2s and a short length of coax would do the trick between two cars parked next to each other. ;>)

-- Mike Flowers, K6MKF, NCDXC - "It's about DX!"

> On Jul 15, 2017, at 5:53 PM, Wayne Burdick <[hidden email]> wrote:
>
> I’m dealing with one of the last unsolved problems in amateur radio: how to operate HF mobile without an antenna. At least not one that, according to some vehicle co-owners/spouses, would defile your new sedan.
>
> For 10 bonus points that have only philosophical value, your challenge is to create an invisible mobile antenna and actually make a QSO on it. For practical purposes (i.e., not frying the car or passengers) let’s say the maximum power level is 10 watts. The bands of interest are 40-10 meters.
>
> Here are some ideas I’m considering:
>
> - mag loop in the rear window
> - thin wire loop on a roof rack
> - gamma match to the entire roof
> - surface acoustic waves
> - prayer
>
> Other ideas?
>
> Yes, I know this violates the laws of physics and bioethics. And I fully expect the car to generate debilitating levels of RFI. But isn’t this the least you’d expect from an unsolved problem?
>
> Thanks in advance,
>
> Wayne
> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Alan Bloom

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

One of my colleagues at HP told me he once made a CB antenna by feeding
the front window of his car between the rear-view mirror and the dash.
Basically a big slot antenna. He claimed it worked great. I don't
remember how he said he matched it to 50 ohms.

Alan N1AL

On 07/15/2017 05:53 PM, Wayne Burdick wrote:

> I’m dealing with one of the last unsolved problems in amateur radio: how to operate HF mobile without an antenna. At least not one that, according to some vehicle co-owners/spouses, would defile your new sedan.
>
> For 10 bonus points that have only philosophical value, your challenge is to create an invisible mobile antenna and actually make a QSO on it. For practical purposes (i.e., not frying the car or passengers) let’s say the maximum power level is 10 watts. The bands of interest are 40-10 meters.
>
> Here are some ideas I’m considering:
>
> - mag loop in the rear window
> - thin wire loop on a roof rack
> - gamma match to the entire roof
> - surface acoustic waves
> - prayer
>
> Other ideas?
>
> Yes, I know this violates the laws of physics and bioethics. And I fully expect the car to generate debilitating levels of RFI. But isn’t this the least you’d expect from an unsolved problem?
>
> Thanks in advance,
>
> Wayne
> N6KR
>

Michael Chowning

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

Spouse proof mobile antenna on that new car:

1) go to a customizing shop, and have them remove your sunroof
2) take the sunroof to a custom glass shop, have them lay out one layer of shatterproof glass
3) you lay out appropriate length thin wire on the glass according to the frequencies you desire; be sure to provide wire lead out
4) have the glass fabricators carefully sandwich another layer of glass
5) take glass sunroof back to the customizing shop to be re-installed
6) for extra bonus points, remember most sunroof tilt up a few degrees, giving it a modicum of directionality
7) for a whole lot of bonus points, tell the customizing shop you want the sunroof to pop up a foot above and for you to be able to rotate it at least a 180 degrees, since there is electrical power, you could even motorized it.

Now all you have to do, is get permission to rack mount your radio in place of the passenger seat.
Seriously, here is a link from Ohio State Unversity on experimental antennas in clothes of the military.

https://news.osu.edu/news/2011/08/22/antcloth/

Mike, N8TTR

> On Jul 15, 2017, at 8:53 PM, Wayne Burdick <[hidden email]> wrote:
>
> I’m dealing with one of the last unsolved problems in amateur radio: how to operate HF mobile without an antenna. At least not one that, according to some vehicle co-owners/spouses, would defile your new sedan.
>
> For 10 bonus points that have only philosophical value, your challenge is to create an invisible mobile antenna and actually make a QSO on it. For practical purposes (i.e., not frying the car or passengers) let’s say the maximum power level is 10 watts. The bands of interest are 40-10 meters.
>
> Here are some ideas I’m considering:
>
> - mag loop in the rear window
> - thin wire loop on a roof rack
> - gamma match to the entire roof
> - surface acoustic waves
> - prayer
>
> Other ideas?
>
> Yes, I know this violates the laws of physics and bioethics. And I fully expect the car to generate debilitating levels of RFI. But isn’t this the least you’d expect from an unsolved problem?
>
> Thanks in advance,
>
> Wayne
> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Randy Bright

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

Would there be a way to repurpose the defrost wiring that is sandwiched
between the layers of glass in some back windows and use that thin wire for
your antenna?

Randy
AK4QK
Member Calhoun County Amateur Radio Assn.
NAQCC #6312

On Jul 15, 2017 7:54 PM, "Wayne Burdick" <[hidden email]> wrote:

> I’m dealing with one of the last unsolved problems in amateur radio: how
> to operate HF mobile without an antenna. At least not one that, according
> to some vehicle co-owners/spouses, would defile your new sedan.
>
> For 10 bonus points that have only philosophical value, your challenge is
> to create an invisible mobile antenna and actually make a QSO on it. For
> practical purposes (i.e., not frying the car or passengers) let’s say the
> maximum power level is 10 watts. The bands of interest are 40-10 meters.
>
> Here are some ideas I’m considering:
>
> - mag loop in the rear window
> - thin wire loop on a roof rack
> - gamma match to the entire roof
> - surface acoustic waves
> - prayer
>
> Other ideas?
>
> Yes, I know this violates the laws of physics and bioethics. And I fully
> expect the car to generate debilitating levels of RFI. But isn’t this the
> least you’d expect from an unsolved problem?
>
> Thanks in advance,
>
> Wayne
> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

Regarding the defrost heat element, there's two terminals, one on either
side. However with the resistance of the defrost wiring in the window,
it might be more like a dummy load. Of course one could just feed one
side against the auto body, unless one drives a Corvette which is mostly
plastic. grrrr

Seems I recall a DDRR antenna which was a low profile, roof mountable
antenna. The 40M version would be a bit large with a diameter of some
9 ft, although one might reduce the size and still make a 40M - 10M of
reasonable dimensions with reasonable efficiency.

73

Bob, K4TAX

K3S s/n 10163

> On Jul 15, 2017 7:54 PM, "Wayne Burdick" <[hidden email]> wrote:
>
>> I’m dealing with one of the last unsolved problems in amateur radio: how
>> to operate HF mobile without an antenna. At least not one that, according
>> to some vehicle co-owners/spouses, would defile your new sedan.
>>
>> For 10 bonus points that have only philosophical value, your challenge is
>> to create an invisible mobile antenna and actually make a QSO on it. For
>> practical purposes (i.e., not frying the car or passengers) let’s say the
>> maximum power level is 10 watts. The bands of interest are 40-10 meters.
>>
>> Here are some ideas I’m considering:
>>
>> - mag loop in the rear window
>> - thin wire loop on a roof rack
>> - gamma match to the entire roof
>> - surface acoustic waves
>> - prayer
>>
>> Other ideas?
>>
>> Yes, I know this violates the laws of physics and bioethics. And I fully
>> expect the car to generate debilitating levels of RFI. But isn’t this the
>> least you’d expect from an unsolved problem?
>>
>> Thanks in advance,
>>
>> Wayne
>> N6KR
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Barry

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Randy Bright

Even if you can get something to radiate, there's always the issue of RFI to the car's electronics. Careful!

Barry W2UP

Kevin Cozens-2

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Randy Bright

On 2017-07-15 11:18 PM, Randy Bright wrote:
> Would there be a way to repurpose the defrost wiring that is sandwiched
> between the layers of glass in some back windows and use that thin wire for
> your antenna?

I was going to mention this. I'm sure that I have read about someone who has
done that. I don't remember if they used the existing wiring in the rear
window or had it redone so it still looked like defrost wiring.

--
Cheers!

Kevin.

http://www.ve3syb.ca/ |"Nerds make the shiny things that distract
Owner of Elecraft K2 #2172 | the mouth-breathers, and that's why we're
| powerful!"
#include <disclaimer/favourite> | --Chris Hardwick
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

k6dgw

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Bob McGraw - K4TAX

The Southern Pacific RR [now Union Pacific] used 160 MHz DDRR antennas
on some of their signalling equipment. Generally on top of a big steel
box beside the track(s). Had a base plate bolted to the box, and a
single 25-30 cm element, parallel to the top of the box, spaced about
6-7 cm above it. The whole antenna looked like it was cast in one
piece. For 20 m, it would be significantly larger, but might be
disguised as, or in, a roof rack. A lot of folks drive around with
stuff piled on their cars these days.

http://www.orionmicro.com/ant/ddrr/ddrr1.htm has some design info

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 7/15/17 8:37 PM, Bob McGraw K4TAX wrote:

> Regarding the defrost heat element, there's two terminals, one on
> either side. However with the resistance of the defrost wiring in the
> window, it might be more like a dummy load. Of course one could just
> feed one side against the auto body, unless one drives a Corvette
> which is mostly plastic. grrrr
>
> Seems I recall a DDRR antenna which was a low profile, roof mountable
> antenna. The 40M version would be a bit large with a diameter of
> some 9 ft, although one might reduce the size and still make a 40M -
> 10M of reasonable dimensions with reasonable efficiency.
>
> 73
>
> Bob, K4TAX
>
> K3S s/n 10163
>
>
>
>> On Jul 15, 2017 7:54 PM, "Wayne Burdick" <[hidden email]> wrote:
>>
>>> I’m dealing with one of the last unsolved problems in amateur radio:
>>> how
>>> to operate HF mobile without an antenna. At least not one that,
>>> according
>>> to some vehicle co-owners/spouses, would defile your new sedan.
>>>
>>> For 10 bonus points that have only philosophical value, your
>>> challenge is
>>> to create an invisible mobile antenna and actually make a QSO on it.
>>> For
>>> practical purposes (i.e., not frying the car or passengers) let’s
>>> say the
>>> maximum power level is 10 watts. The bands of interest are 40-10
>>> meters.
>>>
>>> Here are some ideas I’m considering:
>>>
>>> - mag loop in the rear window
>>> - thin wire loop on a roof rack
>>> - gamma match to the entire roof
>>> - surface acoustic waves
>>> - prayer
>>>
>>> Other ideas?
>>>
>>> Yes, I know this violates the laws of physics and bioethics. And I
>>> fully
>>> expect the car to generate debilitating levels of RFI. But isn’t
>>> this the
>>> least you’d expect from an unsolved problem?
>>>
>>> Thanks in advance,
>>>
>>> Wayne
>>> N6KR
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Clay Autery-2

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Randy Bright

Yep... we owned at least one car growing up that had the antenna in the
windshield.... As I remember it, it came up from the bottom of the
center windshield... two parallel black (tiny) wires. At the top they
each bent out toward the sides of the windshield about 2 inches from the
top... 1 inch diameter or so radius bend, and the horizontal runs were
somewhere around a foot long...

73,

______________________
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 7/16/2017 12:04 PM, Ron D'Eau Claire wrote:
> I thought that was how FM antennas were implemented in some cars already, but without using resistance wire.
>
> 73, Ron AC7AC
>
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Barry Baines

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

Wayne:

> On Jul 15, 2017, at 8:53 PM, Wayne Burdick <[hidden email]> wrote:
>
> I’m dealing with one of the last unsolved problems in amateur radio: how to operate HF mobile without an antenna. At least not one that, according to some vehicle co-owners/spouses, would defile your new sedan.
>
> For 10 bonus points that have only philosophical value, your challenge is to create an invisible mobile antenna and actually make a QSO on it. For practical purposes (i.e., not frying the car or passengers) let’s say the maximum power level is 10 watts. The bands of interest are 40-10 meters.

If the goal is to operate HF while mobile “without an antenna”, why not take an entirely different approach using existing Elecraft product offerings that entirely avoids the issue of trying to mount antennas on vehicles that are becoming less and less “amateur friendly?”

My suggestion is to operate an Elecraft base station remotely while mobile using the K3/0-Mini and RemoteRig 1258MKII in the vehicle tethered to an iPhone or other Smartphone. The K3/0-Mini operates superbly with RemoteRig to connect to base stations. The Smartphone acts as a “Wifi hotspot” in the vehicle; use the WiFi option of RemoteRig 1258MKII to connect to the smartphone or use a separate “WAP” (Wireless Access Point) such as the TPLink TL-WR802N ($20.00) that is tied to the RemoteRig 1258MKII via an ethernet connection between the two.

Depending upon the types of interfaces incorporated at the base station, one can also control the rotor and KPA500 through the web browser of the smartphone if using the RemoteRig RC-1216H to interface to each device at the home station (one RC-1216H for each device).

The ability to operate amateur radio through internet links while mobile has been well established. For example, in the case of DMR (Digital Mobile Radio) offered by various VHF and UHF repeater organizations, I’ve had excellent performance using the RFShark “openSPOT” tied through a TL-802N WAP and connected to the internet via my iPhone 7 “hotspot”. The openSPOT acts as a mini-repeater in the vehicle with RF from a radio (such as a HT) being sent through the internet; likewise, packets received from the internet are broadcast by the openSPOT to the HT in the vehicle. I’ve been able to communicate through two different DMR networks (DMR+ and Brandmeister) while mobile, allowing me to utilize DMR repeater networks while out-of-range of DMR repeaters. This has allowed me to communicate with friends in New England and North Florida/South Georgia when I’m not in repeater coverage within those areas.

In essence, the K3/0-Mini coupled to a RemoteRig 1258MKII and linked to a smartphone via Wifi is taking a similar approach, but with the interface between the K3/0-Mini being hardwired to the RemoteRig 1258MKII. The RemoteRig can be placed under a car seat and the K3/0-Mini can be placed anywhere where the operator can access it just as with a mobile rig control head. If a WAP is used, it can also be placed beneath the seat.

Are there downsides to operating HF via internet back to the home station (or some other locale)? Providing Grid Squares based upon vehicle location is out since the location of the transmitter is what determines which grid square one is operating from, and not the location of operator. Internet quality through cellular networks can vary while mobile, but overall the throughput of the K3/0-Mini using audio CODECs offered by the RemoteRig equipment that require less bandwidth should still work well.

Food for thought,

Barry Baines, WD4ASW
(Currently in Boston, MA)

>
> Here are some ideas I’m considering:
>
> - mag loop in the rear window
> - thin wire loop on a roof rack
> - gamma match to the entire roof
> - surface acoustic waves
> - prayer
>
> Other ideas?
>
> Yes, I know this violates the laws of physics and bioethics. And I fully expect the car to generate debilitating levels of RFI. But isn’t this the least you’d expect from an unsolved problem?
>
> Thanks in advance,
>
> Wayne
> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Phil Kane-2

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Michael Chowning

On 7/15/2017 7:53 PM, Michael Chowning wrote:

> Now all you have to do, is get permission to rack mount your radio in place of the passenger seat.
> Seriously, here is a link from Ohio State Unversity on experimental antennas in clothes of the military.

Seriously -- a certain three-letter agency that I am a survivor of did
the roof-install and rack-install in certain vehicles in the 1970s and
'80s. Some of the early ones were done in my own garage! No longer done!

----
73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Phil Kane-2

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Randy Bright

On 7/15/2017 8:18 PM, Randy Bright wrote:

> Would there be a way to repurpose the defrost wiring that is sandwiched
> between the layers of glass in some back windows and use that thin wire for
> your antenna?

Has been done for sneaky mobile DF systems decades ago. We called then
"defroster antennas" but only got L/R indications. Had to turn the
whole car to get real bearings!

--
73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Phil Kane-2

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Bob McGraw - K4TAX

On 7/15/2017 8:37 PM, Bob McGraw K4TAX wrote:

> Seems I recall a DDRR antenna which was a low profile, roof mountable
> antenna.

Are you referring to what we called the "towel rack" antenna which was
originally made for Air Rescue Helicopters in the Vietnam-War era? They
were replaced by the "defroster antennas".

----

73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Phil Kane-2

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by k6dgw

On 7/16/2017 10:37 AM, Fred Jensen wrote:

> The Southern Pacific RR [now Union Pacific] used 160 MHz DDRR antennas
> on some of their signalling equipment. Generally on top of a big steel
> box beside the track(s). Had a base plate bolted to the box, and a
> single 25-30 cm element, parallel to the top of the box, spaced about
> 6-7 cm above it. The whole antenna looked like it was cast in one
> piece.

Not only the SP, but many other roads as well. That antenna - the
Excalibur by Sinclair - was one of the most popular locomotive antennas
and is also used on signal equipment boxes because it is almost
indestructible. It was originally made to go through a bus wash rack
undamaged! We used them on a series of trucks because of their
ruggedness. They are still being made but they aren't cheap - the VHF
version is in the $150 class.
Depending on the manufacturer, there are two versions, the "exposed"
solid-metal version and one in a fiberglass radome.

> For 20 m, it would be significantly larger, but might be disguised
> as, or in, a roof rack. A lot of folks drive around with stuff piled
> on their cars these days.

We installed a 30-40 MHz version in a fiberglass radome on one truck -
it looked like an inverted canoe! I would put a VHF version on the
family car but the wife settled for a mag-mount. I'm not sure how it
would work with a 2m/440 rig - there's a separate 450 MHz-band version.

--
73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Matthew Cook

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

Mount your iPad/Tablet to the dash, install 3G/4G internet capable router
(internal antennas) into the car, Heil Headset & RR1274 then remote into
your K3/KPA500/KAT500 remote station at home. Works rather nicely.

Otherwise ruggedised whip tuner under the bonnet (err hood) with a thin
discrete stainless steel whip mounted on the front of the car there
somewhere.

73

Matthew
VK5ZM

On 16 July 2017 at 10:23, Wayne Burdick <[hidden email]> wrote:

pa0pje

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by Randy Bright

Not only FM, Ron. In my car it's for both FM, MW and LW
The lines are formed in a strange way, not just horizontal parallel
wires but here and there are openings. It works well on all three bands,
that is until the last MW and LW transmitters are turned off here in
Europe and FM will be left alone... FM is largely swapped for DAB+ at
the moment.

72,
Peter

Op 2017-07-16 om 19:04 schreef Ron D'Eau Claire:
> I thought that was how FM antennas were implemented in some cars already, but without using resistance wire.
>
> 73, Ron AC7AC
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Lyle Johnson

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In my Model S all AM/FM broadcast reception antennas are hidden in the
driver-side mirror housing.

I suggest you simply make a physically small antenna that can fit under
some plastic part of your car. Wayne has a Prius so it is mostly
plastic bodywork providing lots of opportunities.

Then insert the small antenna into a very low loss, extremely high-k
dielectric to make the physically small antenna electrically resonant at
the desired frequency. If it works, patent the dielectric material!

You can then encase a typical satellite TV dish in the same dielectric
and have a very directional HF beam and get around all the HOA problems
for those who operate radio while NOT in their car :-)

Air as a dielectric is so 20th century...

73,

Lyle KK7P

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Russ W9RB

Re: Really OT: Inside-the-vehicle HF antennas (possible bonus points)

In reply to this post by wayne burdick

So I guess this wouldn't qualify as stealthy :)

73, Russ - W9RB