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Hugh's Wild West animal tracking aerial



 
 
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  #1  
Old January 20th 18, 05:42 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default Hugh's Wild West animal tracking aerial

He's tracking some small beast using what appears to be a three element
yagi (with a stub matcher on the driven element.) It looks like it's
tuned to about 200MHz.
This tracking thing always seen to be done with such an aerial using
similar or lower frequencies. The result is that the tracking aerial can
only be a two, three, or four element, so it has very poor directional
characteristics. The fact that the operator has no understanding of RF
so holds the aerial pointing up at the sky or down at the ground can't
help either.
Looking at the product adverts, the polar response diagrams show, as
you'd expect, extremely wide forward lobes, poor front/back radio, and
not much gain.
The tracking seems to depend as much on simply roaming around until
proximity increases the signal strength, rather than taking a bearing
from the aerial and following it.
Why don't these devices use low UHF, so 450 MHz or thereabouts, with a
log periodic receiving aerial and a pre-amp? I don't think problems of
foliage attenuation would be very great at such frequencies. In any case
the extra gain made possible by the use of a multi-element aerial would
compensate.

Bill
Ads
  #2  
Old January 20th 18, 10:00 PM posted to uk.tech.digital-tv
Graham.[_12_]
external usenet poster
 
Posts: 472
Default Hugh's Wild West animal tracking aerial

He's tracking some small beast using what appears to be a three element
yagi (with a stub matcher on the driven element.) It looks like it's
tuned to about 200MHz.
This tracking thing always seen to be done with such an aerial using
similar or lower frequencies. The result is that the tracking aerial can
only be a two, three, or four element, so it has very poor directional
characteristics. The fact that the operator has no understanding of RF
so holds the aerial pointing up at the sky or down at the ground can't
help either.
Looking at the product adverts, the polar response diagrams show, as
you'd expect, extremely wide forward lobes, poor front/back radio, and
not much gain.
The tracking seems to depend as much on simply roaming around until
proximity increases the signal strength, rather than taking a bearing
from the aerial and following it.
Why don't these devices use low UHF, so 450 MHz or thereabouts, with a
log periodic receiving aerial and a pre-amp? I don't think problems of
foliage attenuation would be very great at such frequencies. In any case
the extra gain made possible by the use of a multi-element aerial would
compensate.

Bill


Amatur radio foxhunts on 144Mhz seem to succeed with much the same
equipment.
I've done it on Topband with a ferrite rod aerial.

I wonder what animals these guys were tracking in 2011?
(You will probebly need to download and enlarge).

https://www.flickr.com/gp/g3zvt/bC5s6d
--

Graham.
%Profound_observation%
  #3  
Old January 21st 18, 07:27 AM posted to uk.tech.digital-tv
Brian Gaff
external usenet poster
 
Posts: 7,250
Default Hugh's Wild West animal tracking aerial

I have a feeling that some do use such a system. I recall talking to
somebody even in the 80s in Jersey from the Zoo there that had just been
abroad tracking some kind of animal and their kit looked a bit like a very
large and long toilet roll holder with a handle. I never did establish how
it actually worked though.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bill Wright" wrote in message
news
He's tracking some small beast using what appears to be a three element
yagi (with a stub matcher on the driven element.) It looks like it's tuned
to about 200MHz.
This tracking thing always seen to be done with such an aerial using
similar or lower frequencies. The result is that the tracking aerial can
only be a two, three, or four element, so it has very poor directional
characteristics. The fact that the operator has no understanding of RF so
holds the aerial pointing up at the sky or down at the ground can't help
either.
Looking at the product adverts, the polar response diagrams show, as you'd
expect, extremely wide forward lobes, poor front/back radio, and not much
gain.
The tracking seems to depend as much on simply roaming around until
proximity increases the signal strength, rather than taking a bearing from
the aerial and following it.
Why don't these devices use low UHF, so 450 MHz or thereabouts, with a log
periodic receiving aerial and a pre-amp? I don't think problems of foliage
attenuation would be very great at such frequencies. In any case the extra
gain made possible by the use of a multi-element aerial would compensate.

Bill



  #4  
Old January 23rd 18, 07:11 AM posted to uk.tech.digital-tv
Phi
external usenet poster
 
Posts: 318
Default Hugh's Wild West animal tracking aerial


"Bill Wright" wrote in message
news
He's tracking some small beast using what appears to be a three element
yagi (with a stub matcher on the driven element.) It looks like it's tuned
to about 200MHz.
This tracking thing always seen to be done with such an aerial using
similar or lower frequencies. The result is that the tracking aerial can
only be a two, three, or four element, so it has very poor directional
characteristics. The fact that the operator has no understanding of RF so
holds the aerial pointing up at the sky or down at the ground can't help
either.
Looking at the product adverts, the polar response diagrams show, as you'd
expect, extremely wide forward lobes, poor front/back radio, and not much
gain.
The tracking seems to depend as much on simply roaming around until
proximity increases the signal strength, rather than taking a bearing from
the aerial and following it.
Why don't these devices use low UHF, so 450 MHz or thereabouts, with a log
periodic receiving aerial and a pre-amp? I don't think problems of foliage
attenuation would be very great at such frequencies. In any case the extra
gain made possible by the use of a multi-element aerial would compensate.

Bill



I was commissioned to make a single transistor transmitter back in the
sixties that operated ~100 MHz. It was connected to the speaker of a
radiogram so an aquaintance could spy on the conversations of his wife in
his flat to get divorce evidence.
It could be picked up half a mile away on a standard FM radio.

  #5  
Old January 23rd 18, 01:14 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default Hugh's Wild West animal tracking aerial

On 23/01/2018 08:11, Phi wrote:

I was commissioned to make a single transistor transmitter back in the
sixties that operated ~100 MHz. It was connected to the speaker of a
radiogram so an aquaintance could spy on the conversations of his wife
in his flat to get divorce evidence.
It could be picked up half a mile away on a standard FM radio.


Using the speaker as a mike?

Bill
  #6  
Old January 24th 18, 12:28 AM posted to uk.tech.digital-tv
Graham.[_12_]
external usenet poster
 
Posts: 472
Default Hugh's Wild West animal tracking aerial


"Bill Wright" wrote in message
news
He's tracking some small beast using what appears to be a three element
yagi (with a stub matcher on the driven element.) It looks like it's tuned
to about 200MHz.
This tracking thing always seen to be done with such an aerial using
similar or lower frequencies. The result is that the tracking aerial can
only be a two, three, or four element, so it has very poor directional
characteristics. The fact that the operator has no understanding of RF so
holds the aerial pointing up at the sky or down at the ground can't help
either.
Looking at the product adverts, the polar response diagrams show, as you'd
expect, extremely wide forward lobes, poor front/back radio, and not much
gain.
The tracking seems to depend as much on simply roaming around until
proximity increases the signal strength, rather than taking a bearing from
the aerial and following it.
Why don't these devices use low UHF, so 450 MHz or thereabouts, with a log
periodic receiving aerial and a pre-amp? I don't think problems of foliage
attenuation would be very great at such frequencies. In any case the extra
gain made possible by the use of a multi-element aerial would compensate.

Bill



I was commissioned to make a single transistor transmitter back in the
sixties that operated ~100 MHz. It was connected to the speaker of a
radiogram so an aquaintance could spy on the conversations of his wife in
his flat to get divorce evidence.
It could be picked up half a mile away on a standard FM radio.


I made many of those, but mine invariably used two transistor and an
electret mic. I wouldn't have risked exposing my illegal projects to
the judicial system though, even in a civil case.
--

Graham.
%Profound_observation%
  #7  
Old January 24th 18, 04:20 AM posted to uk.tech.digital-tv
Phi
external usenet poster
 
Posts: 318
Default Hugh's Wild West animal tracking aerial


"Bill Wright" wrote in message
news
On 23/01/2018 08:11, Phi wrote:

I was commissioned to make a single transistor transmitter back in the
sixties that operated ~100 MHz. It was connected to the speaker of a
radiogram so an aquaintance could spy on the conversations of his wife in
his flat to get divorce evidence.
It could be picked up half a mile away on a standard FM radio.


Using the speaker as a mike?

Bill


  #8  
Old January 24th 18, 04:21 AM posted to uk.tech.digital-tv
Phi
external usenet poster
 
Posts: 318
Default Hugh's Wild West animal tracking aerial


"Bill Wright" wrote in message
news
On 23/01/2018 08:11, Phi wrote:

I was commissioned to make a single transistor transmitter back in the
sixties that operated ~100 MHz. It was connected to the speaker of a
radiogram so an aquaintance could spy on the conversations of his wife in
his flat to get divorce evidence.
It could be picked up half a mile away on a standard FM radio.


Using the speaker as a mike?

Bill


Yes

  #9  
Old January 24th 18, 11:09 AM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,448
Default Hugh's Wild West animal tracking aerial

On 24/01/2018 05:21, Phi wrote:

Using the speaker as a mike?

Bill


Yes


I did that once to spy on the other kids in our gang hut. It was basey
and no top but perfectly intelligible.

Bill
 




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