F connectors
 

Any one know what power level an F connector can operate?
John Ferrell W8CCW

F connectors
 

I was being intentionally vague. I was hoping for some experiences or
maybe even documentation. I have never seen it for anything other than
small signal use.

The question arose while experimenting with an RV antenna on a
fiberglass Winnebago. I ordered a 12 foot piece of RG59 with
connectors expecting BNC's. What I received was F connectors. I am
inclined to simply try them.

The initial reasoning was flawed anyway. I am planning a vertical 2
meter dipole, hence the 70 ohm cable. Since I am feeding it with a 50
ohm transceiver output there is going to be a little mismatch wherever
I go. The transceiver does have a maximum output of 50 watts but the
current magmount in a thin sliver of fender does not do well with that
now. RF gets back into the laptop with the GPS software...

I bet that is more than any one wanted to know!
de W8CCW John

On 15 May 2006 05:49:18 -0700, wrote:

John Ferrell wrote:
Any one know what power level an F connector can operate?

In real use it's probably better than a phono plug, and for example
Heath radios use phono plugs (HW-101 etc.) up to the 100W power level
up to 30MHz.

If anything the F connector is going to be a better impedance match
into the VHF than a phono plug!

Actual limit (if you want to push to the hairy edge where the connector
is getting damn hot) will depend on frequency, SWR, cabling, etc., that
you don't tell us.

Tim.
John Ferrell W8CCW

F connectors
 

Allison wrote:
On 15 May 2006 05:49:18 -0700, wrote:

John Ferrell wrote:
Any one know what power level an F connector can operate?

In real use it's probably better than a phono plug, and for example
Heath radios use phono plugs (HW-101 etc.) up to the 100W power level
up to 30MHz.

If anything the F connector is going to be a better impedance match
into the VHF than a phono plug!

Actual limit (if you want to push to the hairy edge where the connector
is getting damn hot) will depend on frequency, SWR, cabling, etc., that
you don't tell us.

Tim.

I'd take a more direct shot. The connector can likely take whatever
the RG59 or other 75 ohm cable limits it too. Likely the limiting
factor is voltage breakdown. At 75ohms you get to higher voltages
for the same power than you would using a 50ohm system.

If it's one of those F connectors that use the centre conductor of the
cable as the 'pin' of the plug, the limit might be the quality of that
connection.

Is the wire short or long? Clean or corroded? Bent or straight? Does it
have a clean-cut end, or was it mashed flat? Who knows...

I'd bet in the 200W range is not unreasonable.

Probably so... and probably more, if desperate enough. But reliability
is a different matter.

F connectors were designed for the cable industry, to be used by the
millions at the lowest possible cost. It doesn't seem like a good idea
to use such connectors in amateur radio, unless there is some other
compelling reason.



--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

F connectors
 

The new breed of compression type F connectors (T&B Snap-N-Seal) have
surprisingly good return loss up to 3 GHz and Canare advertises 26dB
return loss at 2GHz for their industry standard crimp type, see
http://www.canare.com/index.cfm?obje...9D73F542BECA48.
The female F receptacle usually has two fingers that grab the center
conductor and I think this would be the limiting factor in power
handling capacity.
Bob


Ian White GM3SEK wrote:
Allison wrote:
On 15 May 2006 05:49:18 -0700, wrote:

John Ferrell wrote:
Any one know what power level an F connector can operate?

In real use it's probably better than a phono plug, and for example
Heath radios use phono plugs (HW-101 etc.) up to the 100W power level
up to 30MHz.

If anything the F connector is going to be a better impedance match
into the VHF than a phono plug!

Actual limit (if you want to push to the hairy edge where the connector
is getting damn hot) will depend on frequency, SWR, cabling, etc., that
you don't tell us.

Tim.

I'd take a more direct shot. The connector can likely take whatever
the RG59 or other 75 ohm cable limits it too. Likely the limiting
factor is voltage breakdown. At 75ohms you get to higher voltages
for the same power than you would using a 50ohm system.

If it's one of those F connectors that use the centre conductor of the
cable as the 'pin' of the plug, the limit might be the quality of that
connection.

Is the wire short or long? Clean or corroded? Bent or straight? Does it
have a clean-cut end, or was it mashed flat? Who knows...

I'd bet in the 200W range is not unreasonable.

Probably so... and probably more, if desperate enough. But reliability
is a different matter.

F connectors were designed for the cable industry, to be used by the
millions at the lowest possible cost. It doesn't seem like a good idea
to use such connectors in amateur radio, unless there is some other
compelling reason.

F connectors
 

John Ferrell wrote:
I was being intentionally vague. I was hoping for some experiences or
maybe even documentation. I have never seen it for anything other than
small signal use.


If you are looking for direct experience....

My M2 six meter Yagi's use F connectors and I regularly run 1000-1200
watts CW on six meters into one antenna.

The F connectors are in a coaxial feed for a T match, and the way they
are configured each connector has half the line current but there is
full line voltage on each connector. That's on six meters, and I mostly
work CW (sometimes for a few hours straight).

I've used CATV hardline to F connectors for dipoles on HF many times. I
used RG-6 style cable to feed dipoles for low bands, and the F
connectors never failed even with high power.

I was a little scared of the RG-6 and F connectors on my M2 antenna
feed system, but it has not been a problem. I never worried about 1500
watts at 160-40 meters and failure never was an issue. I high pot test
F connector cable assemblies to about 2000 volts peak, so I expect
current or moisture would be the limit.

73 Tom

F connectors
 

On 15 May 2006 18:21:56 -0700, wrote:


watts at 160-40 meters and failure never was an issue. I high pot test
F connector cable assemblies to about 2000 volts peak, so I expect
current or moisture would be the limit.

Tom, whilst they are likely to withstand thousands of volts, small
coaxial cables are unlikely to withstand the heat from the
corresponding current if applied for sufficient time.

The focus in this discussion seems to be solely on the voltage
withstand capability, whereas loss / ability to dissipate heat /
temperature rise as installed are relevant and may be more
constraining.

Owen
--

F connectors
 

Owen Duffy wrote:
On 15 May 2006 18:21:56 -0700, wrote:


watts at 160-40 meters and failure never was an issue. I high pot test
F connector cable assemblies to about 2000 volts peak, so I expect
current or moisture would be the limit.

Tom, whilst they are likely to withstand thousands of volts, small
coaxial cables are unlikely to withstand the heat from the
corresponding current if applied for sufficient time.

The focus in this discussion seems to be solely on the voltage
withstand capability, whereas loss / ability to dissipate heat /
temperature rise as installed are relevant and may be more
constraining.

Owen


But Owen, I've used a variety of F connectors for hundreds of hours at
high power at lower HF and on six meters.

He asked if anyone had direct experience, and I stated what my first
hand experience with them was.

People would be amazed at the amount of power a good grade RG-6 style
cable will handle and how much power that F connector will take.

73 Tom

F connectors
 

On 16 May 2006 01:40:48 -0700, wrote:

....


But Owen, I've used a variety of F connectors for hundreds of hours at
high power at lower HF and on six meters.

He asked if anyone had direct experience, and I stated what my first
hand experience with them was.

People would be amazed at the amount of power a good grade RG-6 style
cable will handle and how much power that F connector will take.

Tom, I agree with you. I use selected RG-6 cable myself, and it is
greatly undervalued. But... my point was mainly, don't focus only on
breakdown voltage, it is certainly a parameter that relates to
instantaneous failure, but heat from losses (principally ohmic loss in
the centre conductor) is an issue and may be more limiting. Of course,
average power under typical voice SSB service is perhaps 2% of the
PEP, so heat becomes less an issue than under higher duty cycle modes.

Discussion of F connectors inevitably leads to RG6. BNC connectors are
readily available (at least over here) for RG6 and are my preferred
choice.

Owen
--

F connectors
 

John Ferrell wrote:
I was being intentionally vague. I was hoping for some experiences or
maybe even documentation. I have never seen it for anything other than
small signal use.

The question arose while experimenting with an RV antenna on a
fiberglass Winnebago. I ordered a 12 foot piece of RG59 with
connectors expecting BNC's. What I received was F connectors. I am
inclined to simply try them.

The initial reasoning was flawed anyway. I am planning a vertical 2
meter dipole, hence the 70 ohm cable. Since I am feeding it with a 50
ohm transceiver output there is going to be a little mismatch wherever
I go. The transceiver does have a maximum output of 50 watts but the
current magmount in a thin sliver of fender does not do well with that
now. RF gets back into the laptop with the GPS software...

I bet that is more than any one wanted to know!
de W8CCW John

On 15 May 2006 05:49:18 -0700, wrote:

John Ferrell wrote:
Any one know what power level an F connector can operate?
In real use it's probably better than a phono plug, and for example
Heath radios use phono plugs (HW-101 etc.) up to the 100W power level
up to 30MHz.

If anything the F connector is going to be a better impedance match
into the VHF than a phono plug!

Actual limit (if you want to push to the hairy edge where the connector
is getting damn hot) will depend on frequency, SWR, cabling, etc., that
you don't tell us.

Tim.
John Ferrell W8CCW

Hi Tim,

I've used them here for years in both HF and VHF work .. have had no
problems at 100w Levels even with swr's as High as 10:1.. give it a shot.
73 Dave KC1DI
by the way for all you G5RV users out there.. RG6 75 ohm and
f-connectors work very will and give a bit better of a match to the G5RV
than the standard 50 oh model.

F connectors
 

Thanks to all, I will use F's in my experimenting. I will probably
need to fabricate an adapter for a UHF to F for the rig output but
that is not a big deal.

de W8CCW John



I've used them here for years in both HF and VHF work .. have had no
problems at 100w Levels even with swr's as High as 10:1.. give it a shot.
73 Dave KC1DI
by the way for all you G5RV users out there.. RG6 75 ohm and
f-connectors work very will and give a bit better of a match to the G5RV
than the standard 50 oh model.
John Ferrell W8CCW