gamma match 70cm handheld
 

"Jerry Martes" wrote in
news:VQiSh.2134$SK3.781@trnddc03:


"Owen Duffy" wrote in message
...
Kurt wrote in news:3McSh.7893$YL5.5717
@newssvr29.news.prodigy.net:

...
Did some testing and I don't have as much directivity but I sure as
heck have plenty of gain with this setup. I might have to get a
loop

Kurt,

Congratulations on your success.

Gain and directivity are related, Gain=Directivity/Loss, or in dB,
Gain(dB)
=Directivity(dB)-Loss(dB).

So whilst it is possible to have gain without directivity (due to
high loss), the reverse doesn't happen.

Owen

Hi Owen

I wonder if I misunderstand. I would think there could alot of ...

No, I messed the words up... it should read:

So whilst it is possible to have directivity without gain (due to
high loss), the reverse doesn't happen.

That makes more sense doesn't it.

Owen

gamma match 70cm handheld
 

Jimmie D wrote:
Kurt wrote:

Well, I had set the program to optimize the antenna for 433Mhz
as that is what I was going to start with on my tracking transmitter.
Plugged the Yagi into my handheld, set the power to low, set the fwd
indication on my SWR meter and then did the ref reading. I was shocked
to see that it was 1:1.2. Set it up to 450Mhz and saw it was 1:1. For
this new ham, it was pretty surprising for a first project.

This is exactly why I never trusted gamma matches on 70 cm. I consistently
got nearly perfectly flat matches all the way across the band using a gamma
match. This usally something aint right. and the antenna is probably
radiating more in the infra-red region than at the desire frequency. No
doubt there are others more skilled than I who can make it work For me the
quagi has worked to damned well for me to bother.

Jimmie.


Thanks for the info Jimmie. I gotta find a 70cm repeater in a
reasonable range and see if I can get some signal reports. As
mentioned, I was tentatively going to use this for RDF so in actuality
I could just connect it to a handheld scanner. I was told though if an
antenna demonstrated a good SWR on transmitting it should be good for
receiving. Sounds like that may not be the truth though judging by your
experience.

Kurt

gamma match 70cm handheld
 

Jerry Martes wrote:
"Kurt" wrote in message
...

Jimmie D wrote:

Kurt wrote:

Well, I had set the program to optimize the antenna for 433Mhz
as that is what I was going to start with on my tracking transmitter.
Plugged the Yagi into my handheld, set the power to low, set the fwd
indication on my SWR meter and then did the ref reading. I was shocked
to see that it was 1:1.2. Set it up to 450Mhz and saw it was 1:1. For
this new ham, it was pretty surprising for a first project.

This is exactly why I never trusted gamma matches on 70 cm. I
consistently got nearly perfectly flat matches all the way across the
band using a gamma match. This usally something aint right. and the
antenna is probably radiating more in the infra-red region than at the
desire frequency. No doubt there are others more skilled than I who can
make it work For me the quagi has worked to damned well for me to bother.

Jimmie.

Thanks for the info Jimmie. I gotta find a 70cm repeater in a reasonable
range and see if I can get some signal reports. As mentioned, I was
tentatively going to use this for RDF so in actuality
I could just connect it to a handheld scanner. I was told though if an
antenna demonstrated a good SWR on transmitting it should be good for
receiving. Sounds like that may not be the truth though judging by your
experience.

Kurt


Hi Kurt

The local repeater is a good source of a test signal, as you indicate.
In addition, have you considered looking for an amateur satellite on 435MHz?
AMSAT has alot of satellite pass prediction information.

Jerry


Haven't considered any satellite attempts but I did try to pick up that
spacesuit they tossed out of the ISS. Saw the ISS streaking across the
sky, which was cool, but didn't hear anything on my scanner with a
simple rubber duck. (Wonder why? sic) :-) That was before I was trying
to study for a ticket.
I'll have to look into it. I suspect if I could hear the beacon I would
be pointing in the right direction then call a CQ and see if I get a reply?

Kurt

gamma match 70cm handheld
 

"Kurt" wrote in message
...
Jimmie D wrote:
Kurt wrote:

Well, I had set the program to optimize the antenna for 433Mhz
as that is what I was going to start with on my tracking transmitter.
Plugged the Yagi into my handheld, set the power to low, set the fwd
indication on my SWR meter and then did the ref reading. I was shocked
to see that it was 1:1.2. Set it up to 450Mhz and saw it was 1:1. For
this new ham, it was pretty surprising for a first project.

This is exactly why I never trusted gamma matches on 70 cm. I
consistently got nearly perfectly flat matches all the way across the
band using a gamma match. This usally something aint right. and the
antenna is probably radiating more in the infra-red region than at the
desire frequency. No doubt there are others more skilled than I who can
make it work For me the quagi has worked to damned well for me to bother.

Jimmie.
Thanks for the info Jimmie. I gotta find a 70cm repeater in a reasonable
range and see if I can get some signal reports. As mentioned, I was
tentatively going to use this for RDF so in actuality
I could just connect it to a handheld scanner. I was told though if an
antenna demonstrated a good SWR on transmitting it should be good for
receiving. Sounds like that may not be the truth though judging by your
experience.

Kurt

Hi Kurt

The local repeater is a good source of a test signal, as you indicate.
In addition, have you considered looking for an amateur satellite on 435MHz?
AMSAT has alot of satellite pass prediction information.

Jerry

gamma match 70cm handheld
 

Kurt wrote:
Jerry Martes wrote:

"Kurt" wrote in message
...

Jimmie D wrote:

Kurt wrote:

Well, I had set the program to optimize the antenna for 433Mhz
as that is what I was going to start with on my tracking transmitter.
Plugged the Yagi into my handheld, set the power to low, set the fwd
indication on my SWR meter and then did the ref reading. I was shocked
to see that it was 1:1.2. Set it up to 450Mhz and saw it was 1:1. For
this new ham, it was pretty surprising for a first project.

This is exactly why I never trusted gamma matches on 70 cm. I
consistently got nearly perfectly flat matches all the way across
the band using a gamma match. This usally something aint right. and
the antenna is probably radiating more in the infra-red region than
at the desire frequency. No doubt there are others more skilled than
I who can make it work For me the quagi has worked to damned well
for me to bother.

Jimmie.


Thanks for the info Jimmie. I gotta find a 70cm repeater in a
reasonable range and see if I can get some signal reports. As
mentioned, I was tentatively going to use this for RDF so in actuality
I could just connect it to a handheld scanner. I was told though if an
antenna demonstrated a good SWR on transmitting it should be good for
receiving. Sounds like that may not be the truth though judging by your
experience.

Kurt



Hi Kurt

The local repeater is a good source of a test signal, as you
indicate. In addition, have you considered looking for an amateur
satellite on 435MHz? AMSAT has alot of satellite pass prediction
information.

Jerry

Haven't considered any satellite attempts but I did try to pick up that
spacesuit they tossed out of the ISS. Saw the ISS streaking across the
sky, which was cool, but didn't hear anything on my scanner with a
simple rubber duck. (Wonder why? sic) :-) That was before I was trying
to study for a ticket.
I'll have to look into it. I suspect if I could hear the beacon I would
be pointing in the right direction then call a CQ and see if I get a reply?

Kurt
Did a radio test with a 10mW beeline transmitter. Put it up in a tree
at 8' and had houses and car dealers in front of me. Lost reception
with an aftermarket Diamond antenna on the H/T at .6mi. Bought some
stuff at a large store like Walmart and put the homemade 7 Element beam
on the H/T in the parking lot.Opened the squelch up and sure enough, I
could readily discern the beeping and hear my callsign and voltage
readings that were transmitted in Morse at 1.3 miles. Had a great F/B
ratio so I could get a bearing. Works good for fringe stuff. Have a
loop for closer in bearing determinations.

Kurt