Hi gang,
I've been thinking about making some homebrew connectors for RG-174/U
coax. I plan to use them to interconnect several enclosures made of PC
board material. I envision something like an SMB connector made from
some of the brass tubing that can be found in hobby shops. Rather than
re-invent the wheel, I thought I would ask here if anyone has done
something like this. The goal is to avoid the large size of something
like a BNC connector along with the attendant high cost of most all RF
connectors.

Tnx!

Bob WB0POQ

"Bob Liesenfeld" wrote in message
...
Hi gang,
I've been thinking about making some homebrew connectors for RG-174/U
coax. I plan to use them to interconnect several enclosures made of PC
board material. I envision something like an SMB connector made from
some of the brass tubing that can be found in hobby shops. Rather than
re-invent the wheel, I thought I would ask here if anyone has done
something like this. The goal is to avoid the large size of something
like a BNC connector along with the attendant high cost of most all RF
connectors.

Tnx!

Bob WB0POQ

Hi Bob,

Why not use SMA or SMB? I used perhaps 30- 40 in my homebrew RX and it makes
for easy fast connect/disconnect. The connectors are cheap as are the crimp
tool. One can assemble a jumper in 3-4 minutes. I would not advise the
RG-174 if you will be doing any soldering. Spend a few pennies more per foot
and use RG-188/RG-316 teflon.

Dale W4OP

Dale Parfitt wrote:

"Bob Liesenfeld" wrote in message
...

Hi gang,
I've been thinking about making some homebrew connectors for RG-174/U
coax. I plan to use them to interconnect several enclosures made of PC
board material. I envision something like an SMB connector made from
some of the brass tubing that can be found in hobby shops. Rather than
re-invent the wheel, I thought I would ask here if anyone has done
something like this. The goal is to avoid the large size of something
like a BNC connector along with the attendant high cost of most all RF
connectors.

Tnx!

Bob WB0POQ

Hi Bob,


Why not use SMA or SMB? I used perhaps 30- 40 in my homebrew RX and it makes
for easy fast connect/disconnect. The connectors are cheap as are the crimp
tool. One can assemble a jumper in 3-4 minutes. I would not advise the
RG-174 if you will be doing any soldering. Spend a few pennies more per foot
and use RG-188/RG-316 teflon.

Dale W4OP



Where do you get connectors? The ones I see in Digi-Key are something
like $5.00 a crack. If I'm missing something please let me know!

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

"Tim Wescott" wrote in message
...
Dale Parfitt wrote:

"Bob Liesenfeld" wrote in message
...

Hi gang,
I've been thinking about making some homebrew connectors for RG-174/U
coax. I plan to use them to interconnect several enclosures made of PC
board material. I envision something like an SMB connector made from
some of the brass tubing that can be found in hobby shops. Rather than
re-invent the wheel, I thought I would ask here if anyone has done
something like this. The goal is to avoid the large size of something
like a BNC connector along with the attendant high cost of most all RF
connectors.

Tnx!

Bob WB0POQ

Hi Bob,


Why not use SMA or SMB? I used perhaps 30- 40 in my homebrew RX and it
makes for easy fast connect/disconnect. The connectors are cheap as are
the crimp tool. One can assemble a jumper in 3-4 minutes. I would not
advise the RG-174 if you will be doing any soldering. Spend a few pennies
more per foot and use RG-188/RG-316 teflon.

Dale W4OP



Where do you get connectors? The ones I see in Digi-Key are something
like $5.00 a crack. If I'm missing something please let me know!

I got mine from The RF Connection in MD. Admittedly I bought perhaps a
hundred or so.

Dale W4OP

See if you can find a drawing of a Peltola connector. This is a very low
cost but high performance connector for RG-174 type cable (having a
solid center conductor) designed by Ron Peltola at Tektronix and used in
Tek scopes and other equipment for many years. You're likely to find
some to look at in just about any analog Tek scope from the '70s onwards.

Roy Lewallen, W7EL

Bob Liesenfeld wrote:
Hi gang,
I've been thinking about making some homebrew connectors for RG-174/U
coax. I plan to use them to interconnect several enclosures made of PC
board material. I envision something like an SMB connector made from
some of the brass tubing that can be found in hobby shops. Rather than
re-invent the wheel, I thought I would ask here if anyone has done
something like this. The goal is to avoid the large size of something
like a BNC connector along with the attendant high cost of most all RF
connectors.

Tnx!

Bob WB0POQ

Bob Liesenfeld wrote:
Hi gang,
I've been thinking about making some homebrew connectors for RG-174/U
coax. I plan to use them to interconnect several enclosures made of PC
board material. I envision something like an SMB connector made from
some of the brass tubing that can be found in hobby shops. Rather than
re-invent the wheel, I thought I would ask here if anyone has done
something like this. The goal is to avoid the large size of something
like a BNC connector along with the attendant high cost of most all RF
connectors.

Tnx!

Bob WB0POQ

What frequencies will you be working at? At HF, RCA or phono plugs are
not perfect and not awfully tiny but they aren't bad and they are
EXTREMELY cheap and widely available and easily assembled. The
impedance bump from each connection will be obviously there but for
most non-measurement HF applications it simply doesn't matter.

The more connections you'll be making or the higher your frequency
(especially above 30MHz), the harder it is to argue that you should
homebrew it from brass tubing. The cost per connector will go down in
bulk, and the reliability you need from each connector will go up.
Homebrewing loses a lot of its fun when you spend more time wiggling
connectors than actually making or using the circuit. At UHF you start
becoming acutely aware of any impedance bumps and the pre-cast
connectors take care of all those details for you very nicely up to
GHz.

As to cost, SMA/SMB/other small connectors and jumpers with preattached
connectors often show up in bulk in the auction places etc.

BNC's will look large if you're laying out PCB's with surface mount
components, that's for sure, and RCA jacks aren't a whole lot smaller.
There are some variants of phono plugs out there that are smaller but
they are not as widely available or as cheap.

Good RF crimpers are not awfully cheap but should be considered in the
TOTAL budget.

Tim.

As to cost, SMA/SMB/other small connectors and jumpers with preattached
connectors often show up in bulk in the auction places etc.
======================================
They can also be found on flea-markets ,being leftovers from mobile
phone cellinstallation contracts..............at least on European flea
markets they are plentyful.

Frank GM0CSZ / KN6WH