Solderless twist-on BNC connectors

[DonTom]

My professionally made BNC cable, between my KX2 and my KXPA100 RF amp, has been giving me intermittent problems and it was a bit too short for what I wanted which was to have the KX2 farther away from the RF amp.

So this morning, after my favorite breakfast place anywhere, the House Of Cheng, I went to the ACE Hardware just across the street. There, they sell RG-59 coax and twist-on solderless BNC connectors, which I have never tried before. I purchased the connectors and a few feet of RG59 cable, among a few other things.

I am impressed! They only take a minute to install, have nothing to solder, and work perfectly.

73, -Don- Tucson, AZ

 

[CharlesinGA]

Your post prompted me to look for adapters I have been craving. My cable to cable modem connection is the typical screw on type, a real PITA when I have to disconnect it in a hurry, due to thunderstorms approaching. I keep wishing I had BNC connectors so I did a search just now, and turned up what I needed. An adapter that would attached to the end of the cable, and an adapter that would screw onto the modem, so I would have a quick BNC connection. Found them at Show Me Cables. Prices seem reasonable, so I will order them.

Charles

 

[DonTom]

Your post prompted me to look for adapters I have been craving. My cable to cable modem connection is the typical screw on type, a real PITA when I have to disconnect it in a hurry, due to thunderstorms approaching. I keep wishing I had BNC connectors so I did a search just now, and turned up what I needed. An adapter that would attached to the end of the cable, and an adapter that would screw onto the modem, so I would have a quick BNC connection. Found them at Show Me Cables. Prices seem reasonable, so I will order them.

Charles

Yeah, they have adapters for everything possible these days. I am glad you found my post to be helpful to you. BNC cables are very simple to make with these twist-ons.

The ones I got at ACE today were these, the JHIU0015.

But you won't even have to bother with that as you have the adapters for both ends there.

-Don- Tucson, AZ

 

[Lou Schneider]

Is your old cable 50 ohms? RG59 is 75 ohms.

 

[DonTom]

Is your old cable 50 ohms? RG59 is 75 ohms.

Yes, but this falls under "who cares?" I certainly don't. And neither does the rig. It is only used to drive my RF amp and I have a lot more drive than I need besides the fact the KX2 tunes to a perfect match into the KXPA100 RF amp. The KX2 (as well as the KXPA100 RF amp) have their own antenna tuners built in.

They do not have the 50-ohm (RG58 or whatever) cable in stock at the ACE Hardware here in Tucson. I would have purchased it instead if they had it, but I didn't care that they didn't as long as they had the 75-ohm RG59 as I knew that would get the job done.

73, -Don- AA6GA/7 (At Tiny's Restaurant in Tucson)

 

[gwinger]

The best and easiest to use are the compression connectors. Once on, they will not pull apart.

You will also need the tool. It has adapters for BNC, F and RCA connectors.

 

[DonTom]

Once on, they will not pull apart.

I doubt these twist-ons will fall apart either. But even if the compression ones hold up better, I still prefer these twist-ons because even if they do pull apart, 20 seconds is all it will take to do a repair job. No tools are required on the connector, so they stay as new. Only a flush cutter is needed for coax. That was the only tool I used today and no tools of any type made contact with the BNC.

-Don- Tucson, AZ

 

[jymbee]

The best and easiest to use are the compression connectors. Once on, they will not pull apart.
View attachment 176333
You will also need the tool. It has adapters for BNC, F and RCA connectors.
View attachment 176334

Perhaps the twist-ons have come a along way since I tried using them some yeas ago. The ones I tried came apart too easily.

Switched to the compression connectors like you posted and haven't had any issues since. Given you have to buy the tool as well, probably no worth it for just a couple of connections.

I've had the compression tool, cutters, cable strippers for some time and they've gotten a lot of use over the years.

 

[DonTom]

The ones I tried came apart too easily.

Mine feel quite tight, yet were not difficult to put together. But perhaps only time will tell.

Mine will get moved around a bit over time. But I am not all that concerned even if they do fall apart as they will only take a few seconds to put back together.

Unless the center of the coax gets broken inside the center pin. That could be a hassle to remove. But even in that case, I will have some spare connectors so still not a big deal. At least not for the way I will be using them. For my use, it's not even important for them to hold up well. I will just make another cable if that happens.

-Don- Tucson, AZ

 

[Mark_K5LXP]

For products I'm involved with a dB of return loss is a big deal along with phase linearity and group delay over a frequency range. Living in the microwave world I generally consider anything under a GHz as being basic RF and anything under 50MHz is just AC. Not true of course but seeing cause/effect of match loss across the spectrum in real world applications, hams just seem hypersensitive to matching that for HF situations is mostly irrelevant. Think of all the obsession with antenna SWR. My favorite is showing up at one Field Day and feeding an antenna with some coax that was spliced in several places with wire nuts. The OCD in the group went into convulsions. Matching can be important in some circuits but for day to day sub VHF stuff it's rarely critical. The only issue I would review with AA6GA's cable isn't the impedance, it's the center pin diameter difference between 50 and 75 ohm BNC's. You can jam a 75 ohm BNC onto a 50 ohm socket but the larger 75 ohm pin can deform the socket. Then when you connect a 50 ohm BNC later, it may not make good contact anymore.

The discussion here reminds me of a photo N3OX posted years ago on the topic of adapter losses.



Mark K5LXP
Albuquerque, NM

 

[DonTom]

The discussion here reminds me of a photo N3OX posted years ago on the topic of adapter losses.

But at what frequency? That could show some big losses at 100 GHz.

Then when you connect a 50 ohm BNC later, it may not make good contact anymore.

I think the female BNC on my KX2 was already getting a little flakey from a lot of use with the 50-ohm cable BNC male. It felt a little loose. Now, it is nice and tight with the 75-ohm male BNC, so the 75-ohm male was more of a fix than a problem.

Yeah, you are right about hams. I forgot to bring one of my antenna analyzers on this trip and even though my TW3030 coil matched fine with my antenna tuner, I just had to get it at the spot where it would be a perfect match without using the antenna tuner in my KXPA100 RF amp (it has a bypass mode). I finally did, but it probably took me an hour's worth of tries to get it right (by squeezing in and out the coils on the TW-3030). Yet I knew nobody would notice any difference in my signal even if I never tried to adjust it.

Yeah, it seems OCD is common among hams regarding matching stuff. But my OCD isn't bad enough to be concerned with the 75-ohm cable between my KX2 and KXPA100 where it was designed for 50 ohms.

73, -Don- AA6GA/7 Tucson, AZ (my 8th day of my "7-day max-no exceptions" stay @ Gilbert Ray).

 

[Mark_K5LXP]

It would be curious to put an SWR meter inline to your amp and check it at typical drive levels on a few bands. Maybe the KX2 has a built in meter? I would guess it's anything but 1:1 most places.

Mark K5LXP
Albuquerque, NM

 

[DonTom]

It would be curious to put an SWR meter inline to your amp and check it at typical drive levels on a few bands. Maybe the KX2 has a built in meter? I would guess it's anything but 1:1 most places.

Mark K5LXP
Albuquerque, NM

I don't think I can bypass the antenna tuner in the KX2, unlike in the KXPA100, so I always have a perfect match anywhere to the RF amp from the KX2. BTW, because of this, I doubt if they even try for 50-ohms at the KX2. Doesn't make a realistic difference when anywhere within reason--as long as the tuner will tune.

I do not have the manual with me, so I cannot look it up, to see if the "ATU" can be bypassed. Playing with the ATU switch is not bypassing it for me. It tunes it, along with unrelated functions, such as sending my auto-CQ.

The KX2 has countless functions. Every control on it has several different functions set by how long and how many times it is pressed in.

 

[DonTom]

And here is the KXPA100 RF Amp. Notice the "ATU mode" switch where I can bypass the ATU:

 

[gwinger]

Perhaps the twist-ons have come a along way since I tried using them some yeas ago. The ones I tried came apart too easily.

Switched to the compression connectors like you posted and haven't had any issues since. Given you have to buy the tool as well, probably no worth it for just a couple of connections.

I've had the compression tool, cutters, cable strippers for some time and they've gotten a lot of use over the years.

For the few more dollars the tool costs, it worth it for the piece of mind that the connector won't fail. Plus, most of the compression fittings are water resistant.
It's an easy way to make custom cables of different lengths. I carry three different ones in my trailer. No more tripping over excess wire.

 

[Lou Schneider]

The only issue I would review with AA6GA's cable isn't the impedance, it's the center pin diameter difference between 50 and 75 ohm BNC's. You can jam a 75 ohm BNC onto a 50 ohm socket but the larger 75 ohm pin can deform the socket. Then when you connect a 50 ohm BNC later, it may not make good contact anymore.

Actually it's the other way around - the 75 ohm center pin is thinner than the 50 ohm version so putting a 50 ohm BNC into a 75 ohm socket can deform the socket.

 

[DonTom]

Actually it's the other way around - the 75 ohm center pin is thinner than the 50 ohm version so putting a 50 ohm BNC into a 75 ohm socket can deform the socket.

Yep, I just now looked it up.

The center conductor of the RG58 (50 ohm) is 20 AWG.

The center conductor of the RG59 (75 ohm) is 22 AWG.

But as long as it works well, which is does, I am satisfied.


-Don- Tucson, AZ

 

[CharlesinGA]

Follow up on my post #2. My order for adapters came promptly, but I screwed up and ordered the wrong female threaded to male BNC adapter. I discovered I had a Type F thread and I had ordered a smaller type SMA threaded adapter.

Then I went to Amazon and found everything I needed and re-ordered more of everything. I will use some of them to convert my 90 year old neighbors Cable modem and digital cable box as he has trouble unscrewing the cables when bad weather shows up (everything he had got zapped last summer, so badly they had to replace the cable up to his house plus the digital box and the cable modem and he TV got hit also, so he is a little gunshy)

Got it all installed this evening and it apparently makes connection and works fine. Now I won't waste time threading the cable connector off the modem every other day when storms hit.

Charles

 

[Wasillaguy]

I agree with most all of the above. If my techs were doing VHF testing, cheap junk adapters were fine. Get up in the Giggies and it's time to call Pasternak and get some real hardware.
And always have a method to sanity check your cables/gear before believing your results.