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Old April 6th 05, 03:46 AM
Pete KE9OA
 
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Default High performance MW receiver

I am finishing up the MW receiver..............anyway, I have a high
impedance antenna input in addition to the 50 ohm input. With this type of
receiver is the high impedance input enough, or would interested parties
rather have both inputs.
The reason I am asking this is because my employer would like to have all
jacks mounted to the main PC board. The only thing I have been able to find
so far has been a right angle BNC connector for the 50 ohm input.
Opinions welcomed!

Pete


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Old April 6th 05, 03:57 AM
RHF
 
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Pete [KE9OA],
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Old April 6th 05, 12:49 PM
Pete KE9OA
 
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The progress is very good for the Loop Antenna, meaning that I built up a
prototype this weekend. It works very well. Later on this week, I will be
doing more experimentation with a regeneration circuit. Since the loopstick
is balanced, I am thinking about adding a feedback winding at each end of
the loopstick; this way, balance is maintained. It uses the common diff-amp,
with a pair of JFETs that are buffered with an emitter follower. I am using
Varactor tuning........the advantage with this approach is
twofold.........first of all, it eliminates that hard to get tuning
capacitor, and secondly, it eliminates the proximity effect from you hand
when tuning because the tuning voltage point for the Varactor is at AC
ground.

Pete

"RHF" wrote in message
oups.com...
Pete [KE9OA],
.
Glad to hear that the work continues
and that the project is near completion.
.
What is the status of your Loop Antenna - Option ?
.
waiting and hoping ~ RHF
. . . . .



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Old April 6th 05, 04:04 AM
 
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In a straight line,it is only fifty miles from where I live here in the
West side of Jackson,Mississippi to Monticello,Mississippi.Will that
radio pick up that AM station in Monticello in the daytime from Jackson
without an external antenna? If not,take it back to the drawing board.
cuhulin

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Old April 6th 05, 12:53 PM
Pete KE9OA
 
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With the active loopstick, it shouldn't be a problem..........that is, if
the signal that you are looking for is above the ambient noise level.
Remember those ads for the Drake SW-4 receiver? They would always say "if
conditions permit, you will be able to hear the signal".
I think you be happy with the radio. I had a visitor from Minnesota a few
weeks ago. When he heard one of the prototypes, he said "let me know when it
hits the market". (slightly paraphrased). He was impressed with the audio
performance of the prototype, and this was just using an LM386 as the audio
amp. The final design will use an automotive power amp, with a really cool
audio processor ahead of it.

Pete

wrote in message
...
In a straight line,it is only fifty miles from where I live here in the
West side of Jackson,Mississippi to Monticello,Mississippi.Will that
radio pick up that AM station in Monticello in the daytime from Jackson
without an external antenna? If not,take it back to the drawing board.
cuhulin





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Old April 6th 05, 04:17 AM
starman
 
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Hi Pete,

If you have to choose only one antenna impedance input, the high one
would probably be more useful, particularly for users of real long wires
like beverage antennas. However those like myself with an inverted-L
which uses a matching transformer and coax lead would appreciate the
50-ohm input.
Is there a reason why you are considering only a BNC connector for the
low impedance input? How about a PC board mounted female F-connector
which can be adapted by the users to their antenna lead wire.

Any idea on when the MW receiver may hit the market?

Pete KE9OA wrote:

I am finishing up the MW receiver..............anyway, I have a high
impedance antenna input in addition to the 50 ohm input. With this type of
receiver is the high impedance input enough, or would interested parties
rather have both inputs.
The reason I am asking this is because my employer would like to have all
jacks mounted to the main PC board. The only thing I have been able to find
so far has been a right angle BNC connector for the 50 ohm input.
Opinions welcomed!

Pete


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Old April 6th 05, 07:00 AM
Michael A. Terrell
 
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starman wrote:

Hi Pete,

If you have to choose only one antenna impedance input, the high one
would probably be more useful, particularly for users of real long wires
like beverage antennas. However those like myself with an inverted-L
which uses a matching transformer and coax lead would appreciate the
50-ohm input.
Is there a reason why you are considering only a BNC connector for the
low impedance input? How about a PC board mounted female F-connector
which can be adapted by the users to their antenna lead wire.



The "F" connectors are 75 ohm impedance.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida
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Old April 6th 05, 12:57 PM
Pete KE9OA
 
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I have decided to include the SO-239 connector.

Pete

"Michael A. Terrell" wrote in message
...
starman wrote:

Hi Pete,

If you have to choose only one antenna impedance input, the high one
would probably be more useful, particularly for users of real long wires
like beverage antennas. However those like myself with an inverted-L
which uses a matching transformer and coax lead would appreciate the
50-ohm input.
Is there a reason why you are considering only a BNC connector for the
low impedance input? How about a PC board mounted female F-connector
which can be adapted by the users to their antenna lead wire.



The "F" connectors are 75 ohm impedance.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida



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Old April 7th 05, 03:31 AM
starman
 
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"Michael A. Terrell" wrote:

starman wrote:

Hi Pete,

If you have to choose only one antenna impedance input, the high one
would probably be more useful, particularly for users of real long wires
like beverage antennas. However those like myself with an inverted-L
which uses a matching transformer and coax lead would appreciate the
50-ohm input.
Is there a reason why you are considering only a BNC connector for the
low impedance input? How about a PC board mounted female F-connector
which can be adapted by the users to their antenna lead wire.


The "F" connectors are 75 ohm impedance.


Technically true for VHF and UHF but not that important for MW or HF
reception. I use R6U coax (75-ohm) for my HF antenna lead.

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Old April 7th 05, 03:53 AM
Michael A. Terrell
 
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starman wrote:

"Michael A. Terrell" wrote:

The "F" connectors are 75 ohm impedance.


Technically true for VHF and UHF but not that important for MW or HF
reception. I use R6U coax (75-ohm) for my HF antenna lead.


Having worked in TV broadcast and with critical telemetry video, it
does matter in a lot of applications at these frequencies. Use what you
want, but I prefer to use the proper connectors for the application, and
"F" connectors are not known for high reliability. When I ran the
repair facility for United Video one of my jobs was to test sample
connectors. A high percentage of "F" connectors didn't pass the basic
tests. They were flimsy, had bad swages between the parts and poor
plating. LIke some beautiful samples we got. They passed every test
except plating. They were un-plated brass that corroded just from body
oils.
--
Former professional electron wrangler.

Michael A. Terrell
Central Florida


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