[TowerTalk] RF Inquiry HI-Q Filter CF5KV

[Jim W7RY]

Take a look at this site:  http://users.erols.com/rfc/Choke%20Kit.htm

This item is a 2 ft piece of RG-213 with a male and female UHF connector 
attached. I have one but it has not been tested.


Here is an excerpt from their page on this product:

Specifications
Frequency:  1.8 – 60 MHz
Through-line impedance:  50 ohms (nominal)
Insertion loss: less than 0.2 dB at 60 MHz
Common mode inductance: 24 uH (nominal)
Power handling: 2kW continuous duty
Load mismatch tolerance:  greater than 5:1 VSWR at 2kw
Connectors:  PL-259 and SO-239
Ferrite material:  seven Fair-Rite P/N 2643102002 (850 Initial Perm, 2900 
gauss at 10 oersteds, nickel-zinc)


73
Jim W7RY




At 10:08 AM 2/21/2005, Jim Lux wrote:

>----- Original Message -----
>From: "Michael Tope" <W4EF at dellroy.com>
>To: "Jim Lux" <jimlux at earthlink.net>; "Rob Atkinson, K5UJ"
><k5uj at hotmail.com>; <towertalk at contesting.com>
>Sent: Monday, February 21, 2005 9:50 AM
>Subject: Re: [TowerTalk] RF Inquiry HI-Q Filter CF5KV
>
>
> > Cable Xperts advertises that they will build custom coax jumpers
> > to order. It wouldn't surprise me if you could arrange to send them
> > the beads and let them do the assembly. Might be a good thing
> > for a group buy.
>
>That's half way to a solution. If you're buying toroids in real quantity,
>they get a LOT cheaper (from reduced shipping costs, if nothing else). I was
>just thinking that there are several suppliers of bead baluns in a PVC pipe.
>Would it affect their sales materially if they were to tell you what
>material and how many beads of what size?  Probably not, and then you could
>buy the product without worrying about what the performance might be.
>
>I can understand that if there were some proprietary design that they didn't
>want to have stolen, but I don't really think that's the case here.  The NRE
>for this kind of product is very, very low, and the fraction of time spent
>figuring out what beads to use is correspondingly low (assuming they don't
>just copy the design out of a handbook).  Therefore, the only real
>distinguishing feature between the various makes is the manufacturing cost
>and quality, which is something that will be different for a competitor (not
>necessarily better or worse, but just different).  For instance, a mfr might
>get a real good price on beads that another didn't. (perhaps due to large
>quantity, or physical location, or just better shopping around), but
>ultimately, the beads are a commodity item.
>
>You bring up an interesting idea, though.  Maybe CableXperts would be
>willing to do all the steps, including procuring the ferrites.  Sometimes,
>all it takes is an indication from the market that a product is needed.
>
>
>  You can also just buy a pre-made RG-8X jumper
> > and wrap several turns around an FT-240-77 core if you need a
> > good common-mode choke for the lower HF bands (2 cores
> > in series with 6 turns each will give about 1100 ohms common-
> > mode impedance on 160 meters and 900 ohms on 80 meters).
> > You can easily get 5 or 6 turns through the core even with PL-259's
> > installed. Cost would be about $15.00 for the jumper and $10 for
> > the 2 cores.  If you need better suppression towards the middle of
> > the HF range, you can substitute FT-240-43 cores in place of the
> > -77 ones. The 43 cores will give an impedance peak around
> > 12 MHz.
> >
> > 73 de Mike,
> > W4EF.................................................................
> >
>
>_______________________________________________
>
>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
>Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
>any questions and ask for Sherman, W2FLA.
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk at contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk