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+--- Thread: Ladder line Quick connections (/thread-640.html)
Ladder line Quick connections - VK4AQJ - 20-09-2018
I'm trying to find something that probably doesn't exist. I use 450Ohm Ladder line for my MF ATU, and I use the same line for 160metres. I have to make and break the connection every time I switch from one to the other.
At the moment, I'm using MC4 solar power connectors. They are weatherproof, will withstand movement of the ladder line due to wind, and you can make and break the connection using a special MC4 spanner. I use male and female connectors on the two terminals so that I can only connect them one way.
The MC4 connectors are ok, but they are a bit fiddly to disconnect, especially in the dark, (OK, I could install a light) and they seem like overkill in terms of size, rating etc.
The question is - Is there something already available for make and break connections on 450 Ohm ladder line? THey have to be robust and weatherproof. I've tried searching with no luck, but maybe it has a special name that I'm unaware of. (or it doesn't exist)
RE: Ladder line Quick connections - VK4ADC - 20-09-2018
It may not be spaced correctly for 450 ohm line but in the early days when everybody used open line feeders :
http://www.ssapl.com.au/product/44486-knife-switch-double-pole-double-throw
Then again, you could disassemble the basic bits from this and reassemble on a different insulating material (eg kitchen chopping board) with the spacing set up differently to maintain the 450 ohm spacing.
RE: Ladder line Quick connections - VK4WDM - 20-09-2018
(20-09-2018, 06:47 AM)VK4ADC Wrote: It may not be spaced correctly for 450 ohm line but in the early days when everybody used open line feeders :
http://www.ssapl.com.au/product/44486-knife-switch-double-pole-double-throw
Then again, you could disassemble the basic bits from this and reassemble on a different insulating material (eg kitchen chopping board) with the spacing set up differently to maintain the 450 ohm spacing.
Yep, good ole knife switch! A change in spacing for a few cms is unlikely to cause much of problem. You could mount it in a box with a push rod coming out of the bottom to water-proof it and it should be easy to devise a remote way of doing the push-pull from inside the shack.
73
Wayne VK4WDM
RE: Ladder line Quick connections - VK4AQJ - 21-09-2018
Good idea! I was asking the wrong question. As Wayne said, the spacing would not be too much of an issue. Remote operation is less of an issue, as all I have to do is walk across to the tuner out on the deck, which I can adjust while watching the SWR.
I started off using binocular glasses to see the SWR, but now I have a sheet magnifier in a frame mounted in front of the digital display so that I can read it from outside while making the adjustment.
73 - Jim VK4AQJ
RE: Ladder line Quick connections - VU2NAN - 19-01-2019
Hi OM Jim,
Should you ever need remote operation, a DPDT Latching Relay would be the right choice as it would obviate the need to keep relay coils on continuously.
73,
Nandu.
RE: Ladder line Quick connections - VK4ADC - 20-01-2019
(19-01-2019, 04:27 PM)VU2NAN Wrote: Hi OM Jim,
Should you ever need remote operation, a DPDT Latching Relay would be the right choice as it would obviate the need to keep relay coils on continuously.
73,
Nandu.
Nandu
The physical closeness of the pairs of DPDT relay contacts within a single relay unit would not retain the 450 ohm characteristic impedance of the open wire line. The other issue might be that we don't know what RF transmitter power level is involved so finding a latching relay to handle the RF current might be difficult, let alone the breakdown voltage rating (high Z = high voltages).
Most latching relays require the polarity to be changed for subsequent changeovers so that might complicate the switching control arrangements slightly. (Yes, I am aware that some latching relays have two coils but they aren't commonly found.)
I use SMA latching relays in my microwave transverters and use a "buck" electrolytic capacitor arrangement in series with the coil and the +12V to snap them in quickly and then the quiescent relay current reduces to a very low nominal value. Works well except you must make sure that the latching state is set on initial power-up so that you know which way it is set (ie Tx or Rx).
RE: Ladder line Quick connections - VU2NAN - 20-01-2019
Hi OM Doug,
In that case OM Jim's best bet is the DPDT knife switch!
Many thanks.
73,
Nandu.
RE: Ladder line Quick connections - VK5ZD - 20-01-2019
(20-01-2019, 10:58 AM)VK4ADC Wrote: The physical closeness of the pairs of DPDT relay contacts within a single relay unit would not retain the 450 ohm characteristic impedance of the open wire line.
You could use two relays spaced the right distance apart. Automotive relays would probably do if you don't mind keeping the coils energised.
Another option would be to use just the centre pin of 2 standard connectors (e.g. BNC, N, etc.) if you prefer something that can be physically disconnected.
RE: Ladder line Quick connections - VK4AQJ - 04-03-2019
(20-01-2019, 04:43 PM)VU2NAN Wrote: Hi OM Doug,
In that case OM Jim's best bet is the DPDT knife switch!
Many thanks.
73,
Nandu.
- and that's exactly what I did! - but thank you for the suggestion anyway.
RE: Ladder line Quick connections - VK6ZFG - 04-03-2019
It would appear as if the feeder is used at MF.
If so, any impedance irregularity by what ever system is used will have little impact at MF.
What is used will however need to be suitable for the voltage present at that point. This may or may not be an issue. It will also need to cater for the weather/environment location.
The challenge is finding some simple, readily used connectors to do the job. 2 pole connectors would make life easy. How about sealed multipole automotive connectors you now can get?
73s
Igor
RE: Ladder line Quick connections - VK2CSW - 04-03-2019
How about Anderson Connectors?
I use the 50 Amp version for 12 v camp wiring - they're quite robust and readily available.
https://www.jaycar.com.au/anderson-50a-power-connector-8-gauge-contacts/p/PT4425
RE: Ladder line Quick connections - VK6ZFG - 04-03-2019
Type of automotive connectors I had in mind.
https://www.ebay.com/itm/Waterproof-Connector-Plug-2-Pin-socket-Wire-Seal-Automotive/352564252574?hash=item5216778f9e:g:iEUAAOSwC9hcNcjH:rk:6:pf:0
Could use ones with more poles and leave out the inner ones to increase spacing if that is desired.
https://www.ebay.com/itm/Practical-Car-1-2-3-4-5-6-Pin-Wire-Way-Electrical-Connector-Terminal-Blade-Fuses/372508945149?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3De43441f33f7242d0a8fc6c33021d0ff7%26pid%3D100005%26rk%3D4%26rkt%3D12%26sd%3D112497498101%26itm%3D372508945149&_trksid=p2047675.c100005.m1851
Just a matter of looking through the multiple choices out there.
Originally though of the 30A Andersons but decided against them as they are not weatherproof
Igor
RE: Ladder line Quick connections - VK3RX - 05-03-2019
My open wire line is about 100mm apart and goes to a remote antenna coupler under the eaves of the house.
About 300mm away from the coupler I have automotive bullet connectors on each line for quick disconnect in case of storms. These are covered for water proofing, but I'm also looking for something better.
These have caught my eye:
https://www.jaycar.com.au/waterproof-solar-power-pv-connector-4mm-male/p/PP5102
https://www.jaycar.com.au/waterproof-solar-power-pv-connector-4mm-female/p/PS5100
RE: Ladder line Quick connections - VK4AQJ - 29-10-2019
I solved this problem with a knife switch, which is still working great. Thanks for all the suggestions though.
(05-03-2019, 01:51 PM)VK3RX Wrote: My open wire line is about 100mm apart and goes to a remote antenna coupler under the eaves of the house.
About 300mm away from the coupler I have automotive bullet connectors on each line for quick disconnect in case of storms. These are covered for water proofing, but I'm also looking for something better.
These have caught my eye:
https://www.jaycar.com.au/waterproof-solar-power-pv-connector-4mm-male/p/PP5102
https://www.jaycar.com.au/waterproof-solar-power-pv-connector-4mm-female/p/PS5100
Yes, those are the ones I used originally. They are good and waterproof. You might have to built up the insulation thickness for them, but that shouldn't be a problem.