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echristley(at)nc.rr.com
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 Posted: Wed Oct 17, 2007 7:48 am Post subject: RG-174? |
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I built a transponder antennae, and the plans I used called for using a
surface mount SMA connector. Good enough, but now to get cable to match
to it. I happened to have a spare antennae for my wireless router, with
an SMA connector on one end. Inspect the cable, and it's RG-174.
I haven't a clue what RG-174 is.
Google-time. Search for "coax cable RG-174". The first hit is an ad,
but the second one appears to be REAL information. John Bryant and Bill
Bowers (didn't he design some antennae for airplanes?) ran some tests on
the stuff. Appears that using it could cost you a dB...if you need
100ft. I need about 8, and I could make it shorter if I HAD to.
So the question. Is there any reason NOT to use this thin, light, cheap
cable?
Just to take the obvious off the table:
It can be delicate...Fix that with proper routing and strain relief.
Those connectors are awfully small for my fat fingers...Deal with it,
and do it over till you get it right.
I'm thinking I will do good to cut the cable off this antennae since it
already has the SMA connector and I know it works.
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mprather(at)spro.net
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| Posted: Wed Oct 17, 2007 8:58 am Post subject: RG-174? |
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Why not use surface mount BNC connector? Or, why not use an SMA connector
on the end of RG-400. I think one of the connectors listed on this page
might work:
http://www.smelectronics.us/smacableconnectorsa.htm
Then again, you can buy premade cables with SMA on one end and BNC on the
other. Eliminates the need to find correct crimp tools. If it's RG-174,
as you pointed out, the losses will be small for short runs.
Regards,
Matt-
| Quote: |
<echristley(at)nc.rr.com>
I built a transponder antennae, and the plans I used called for using a
surface mount SMA connector. Good enough, but now to get cable to match
to it. I happened to have a spare antennae for my wireless router, with
an SMA connector on one end. Inspect the cable, and it's RG-174.
I haven't a clue what RG-174 is.
Google-time. Search for "coax cable RG-174". The first hit is an ad,
but the second one appears to be REAL information. John Bryant and Bill
Bowers (didn't he design some antennae for airplanes?) ran some tests on
the stuff. Appears that using it could cost you a dB...if you need
100ft. I need about 8, and I could make it shorter if I HAD to.
So the question. Is there any reason NOT to use this thin, light, cheap
cable?
Just to take the obvious off the table:
It can be delicate...Fix that with proper routing and strain relief.
Those connectors are awfully small for my fat fingers...Deal with it,
and do it over till you get it right.
I'm thinking I will do good to cut the cable off this antennae since it
already has the SMA connector and I know it works.
|
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echristley(at)nc.rr.com
Guest
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| Posted: Wed Oct 17, 2007 11:45 am Post subject: RG-174? |
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Matt Prather wrote:
| Quote: |
Why not use surface mount BNC connector? Or, why not use an SMA connector
on the end of RG-400.
|
The plans said to use SMA. The antennae is awfully small, and so the
SMA didn't seem like a half bad idea.
http://ernest.isa-geek.org/Delta/Pictures/TransponderAntennae.jpg
Most of all, I think you missed the part where I said I have a cable in
hand. 8*) Changing to BNC might be a good experiment...except that I
already have a cable in my hand.
The question was directed more at the suitability of RG-174. There's a
lot of back and forth about RG-58 vs RG-400, but RG-174 I've not heard
about. It is MUCH thinner, more flexible, no more expensive, just as
available (now that the RatShack is useless and everything is ordered
off the internet anyway) and lighter. I'm looking for a solid reason
NOT to use it, because I've not heard about it and those unknown
unknowns are the ones that will get you killed. Other than that minor
detail, it looks like a winner all the way around.
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mprather(at)spro.net
Guest
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| Posted: Wed Oct 17, 2007 12:28 pm Post subject: RG-174? |
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Sorry, I did miss the fact that you already have a cable.. If it's not
too difficult to swap it later, I'd try running the cable you already have
- it's paid for. If the performance isn't acceptable, change it for
something lower loss at TXP frequency. I notice that around 1000MHz,
RG-174 is significantly more lossy than the larger diameter cables..
There will be a measurable drop in radiated power (if you chose to look),
but that might not affect system performance noticeably. TXP works line
of sight, and the ground station antennas are likely pretty well
optimized.
Regards,
Matt-
| Quote: |
<echristley(at)nc.rr.com>
Matt Prather wrote:
>
> <mprather(at)spro.net>
>
> Why not use surface mount BNC connector? Or, why not use an SMA
> connector
> on the end of RG-400.
The plans said to use SMA. The antennae is awfully small, and so the
SMA didn't seem like a half bad idea.
http://ernest.isa-geek.org/Delta/Pictures/TransponderAntennae.jpg
Most of all, I think you missed the part where I said I have a cable in
hand. 8*) Changing to BNC might be a good experiment...except that I
already have a cable in my hand.
The question was directed more at the suitability of RG-174. There's a
lot of back and forth about RG-58 vs RG-400, but RG-174 I've not heard
about. It is MUCH thinner, more flexible, no more expensive, just as
available (now that the RatShack is useless and everything is ordered
off the internet anyway) and lighter. I'm looking for a solid reason
NOT to use it, because I've not heard about it and those unknown
unknowns are the ones that will get you killed. Other than that minor
detail, it looks like a winner all the way around.
|
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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