Using F-Connectors with 50 Ohm RG8
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theoleman
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I'm sorry in English I think that comes out as..."I'm new here and you know nothing, and I'm going to insult you in my 3rd post"
Blackswan73
Active Member
My original username in my FTA days was Blackswan. I was well known in the FTA satellite community. My avatar was a lobby card from the 1942 film. I have since those days always signed my posts B.S. which is short for Blackswan
B.S.
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RFI-EMI-GUY
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M squared, routinely uses F connectors for 75 ohm phasing lines on their circular polarized satellite antennas.
paulears
Member
I read that totally the other way around, as in
Great responses, this topic lacked any quantifiable research by actual people who have experience with this type of Line use.
i read as I didn't have any experience of this, so came to the forum to ask? He was talking about the topic of using F type connectors, finding no online info, and pleased we came up with potential positive evidence it actually worked.
maybe i wanted to assume only a loony would join and then slap people who replied. Surely he didnt mean to do that?
i personally hate SMA and F types because of the fragility, and difficulty of making good connections. RG8, with proper connector into a series of adaptors or short flimsy cables to relieve the weight just scream ‘break me’, and as i am clumsy, usually do. I guess it’s if you have to it is OK, but just not a first choice.
Great responses, this topic lacked any quantifiable research by actual people who have experience with this type of Line use.
i read as I didn't have any experience of this, so came to the forum to ask? He was talking about the topic of using F type connectors, finding no online info, and pleased we came up with potential positive evidence it actually worked.
maybe i wanted to assume only a loony would join and then slap people who replied. Surely he didnt mean to do that?
i personally hate SMA and F types because of the fragility, and difficulty of making good connections. RG8, with proper connector into a series of adaptors or short flimsy cables to relieve the weight just scream ‘break me’, and as i am clumsy, usually do. I guess it’s if you have to it is OK, but just not a first choice.
G7RUX
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The only real issue with SMA connectors on the top of a set is that they don’t last that well with lots of connection cycles. The connectors themselves are very good and stable but not hugely strong and SMA antennas effectively require that you spin the whole connector which is not brilliant for the centre contacts.
I tend to fit an adaptor to serve as a “connector saver” for precisely this reason.
I tend to fit an adaptor to serve as a “connector saver” for precisely this reason.
I thought the thread was about F connectors.
I have encountered what looks like purpose made F connectors on a few 50 ohm factory made cables in an 50 ohm system but it’s rare. I’ve also drilled out center pins for RG-59 connectors and used RG-58 in a pinch and sometimes you gotta improvise to finish a project. In some testing I’ve done using a 75 ohm connector on 50 ohm cable in a 50 ohm system is not that bad because the internal length of the 75 ohm connector is fairly short and will only cause concerning VSWR problems at higher frequencies, like 500MHz and above.
If you have a 75 ohm system and you stick a length of 50 ohm cable in it using a 75 ohm connector, that’s a different story and you will create VSWR problems.
If you have a 75 ohm system and you stick a length of 50 ohm cable in it using a 75 ohm connector, that’s a different story and you will create VSWR problems.
paulears
Member
F or SMA, very similar, apart from the connectors that use the centre of the coax as the pin. The copper of the typical satellite cable tarnishes quickly and always make poor contact at some point. F types with proper pins and easy connection are not that common, are they!
Compression type F connectors seal the coax and there is no tarnishing of the copper and I’ve never seen a poor contact in my long career in the satellite industry. BTW, I have many VNA bench hours testing and qualifying F connectors for one of the largest satellite provides in the world.
Some older SMA connectors made by MA/Com on rigid copper .141 cable use the center conductor as the center pin, otherwise all other SMA connectors have a separate center pin. I still have a MA/Com kit that has the trimmer to put a rounded point on .141 semi rigid for a center pin but it haven’t been used in about 30yrs.
Great info, thanks.
Do the F type compression connectors they sell at home depot check out ok?
Thanks
Joel
I’ve not tested those. I prefer Thomas & Betts Snap N Seal but PPC was approved for use all over the US by our company when I was still working. I buy the red Snap N Seal SNS1P6U for personal use as they will work with single through quad shield If needed.
Does this assume that the connector is installed on the coax and then connected to a mating connector soon after the coax is stripped? IOW, before the copper has a chance to tarnish?
On a female F connector, what material is typically used for the center pin "receptacle"? Does it stay tarnish free? Does does the female receptacle wipe tarnish from the copper male pin as the connectors are mated?
Connector installed and attached to something during an install, usually within a few hours. Not sure what the female fingers are made of. There usually plated with a silver metal and taking apart equipment that’s been outdoors in a marine environment for 20yrs the silver fingers can look a little dull but I’ve never encountered one that had any high resistance problems. Compression F connectors seal very well onto the female connector and in commercial installs I always wrapped the F connectors for even better moisture resistance.
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Lot's of good ideas from the guys. For me when using F compression connectors I try to get a little fold-back on the braid. And a little sick-out on the stinger. There is a flaring tool that helps stretch the outer insulation a touch so you can press the fitting over your coax and not screw up the folded braid. A Bic and careful massaging with a small screwdriver does about the same.
In any case where the connection is exposed to weather I put a dab of silicone dielectric grease just behind the outer jacket before pressing the fitting on. And then work another dab into the crimp....before crimping.
I like to make sure the inner insulation 'just' pokes out of the inner hole of the connector so it butt's up tight on the mating connector.
Who uses a torque wrench? My spectrum analyzer is adamant on using one for SMA connectors. It came with one and I use it.
And a "good" catv installer/tech will always use one. Not really necessary if you eat your Wheaties and use common sense but don't go gorilla-tight. You know. Common sense will make you an old fart like me and bus free in crosswalks.
When it's all done wipe off any ooze out. If you want a good water seal. I really like Flex Seal spray.
I use it on all of my N Type connectors outdoors. After 6+ years I replaced a length of the infamous Belden 9913 that everyone says is prone to moisture ingress. Swapped it out for LMR-400 from HRO and used the same type of N compression connectors. Should have saved my money. The 9913 will live for another project.
I've found that some of the Home Depot F connectors used with quad shield coax do not play nice with it. Quad shield is rather bulky and some of the cheap crimp connectors with the clear plastic ring just did not like to have the coax pressed in.
So definitely check coax compatibility when grabbing a box of them. Quad shield connectors on single shield will not go on easy and the crimp won't compress over the jacket well.
That's my two cents.
In any case where the connection is exposed to weather I put a dab of silicone dielectric grease just behind the outer jacket before pressing the fitting on. And then work another dab into the crimp....before crimping.
I like to make sure the inner insulation 'just' pokes out of the inner hole of the connector so it butt's up tight on the mating connector.
Who uses a torque wrench? My spectrum analyzer is adamant on using one for SMA connectors. It came with one and I use it.
And a "good" catv installer/tech will always use one. Not really necessary if you eat your Wheaties and use common sense but don't go gorilla-tight. You know. Common sense will make you an old fart like me and bus free in crosswalks.
When it's all done wipe off any ooze out. If you want a good water seal. I really like Flex Seal spray.
I use it on all of my N Type connectors outdoors. After 6+ years I replaced a length of the infamous Belden 9913 that everyone says is prone to moisture ingress. Swapped it out for LMR-400 from HRO and used the same type of N compression connectors. Should have saved my money. The 9913 will live for another project.
I've found that some of the Home Depot F connectors used with quad shield coax do not play nice with it. Quad shield is rather bulky and some of the cheap crimp connectors with the clear plastic ring just did not like to have the coax pressed in.
So definitely check coax compatibility when grabbing a box of them. Quad shield connectors on single shield will not go on easy and the crimp won't compress over the jacket well.
That's my two cents.
These are the standard tools for most satellite system installers. There should be no folding or stretching the braid or leaving the center conductor long. You make sure the cable is squished back round after cutting, strip, push connector on until the dielectric is flush with the edge of the connector then compression crimp. Done.
Many people cut the coax then try and strip and crimp cable that is still flattened from cutting and it needs to be round. Or if you use cheap connectors that don’t have a good fit and sharp edge that rides under the foil/braid you will snag the braid. At one time I was a SBCA certified trainer/instructor (I trained the trainers) and you would have failed my class.
I’ve been heavily involved in commercial and residential satellite for a long time and have called the shots at a high level on certain hardware to be used in the field. Never had the need for such a device nor has DirecTV, Dish or any other satellite provider that I know of. Just DirecTV and Dish alone account for over 50 million installs. In case you read that wrong it’s well over Fifty Million Installs.
I suppose companies are willing to make more tools for those who don’t know how to use the intended ones.
