Hi Ian, All points noted and I do appreciate that a few 6M repeaters
in the UK do use the heliax design but I do wonder how stable and
efficient they are compared with a set of 4 Wacoms or similar. I
must admit that I have 8 suitable lenghs of LDF750 that has been
donated by our understanding aerial riggers but have not yet got a
soldering iron to them! I do however intend to make one stub and see
how that looks on a spectrum anyliser....I suppose in this weather I
could leave it out in the cold for a couple of hours and test it and
let it warm back up and test it again to see it's stability.
Having spoke to those that have got proper cans on their repeaters
they all recommend going down the can route (despite the expence)
Cheers Dave UZN
ps.....Still looking for someone with a set of cans for sale.
--- In Repeater-Builder@yahoogroups.com, "IM Ashford"
<[EMAIL PROTECTED]> wrote:
>
> Dave,
> Having looked at the GB3FH website,this duplexer looks to be self
compensating.
>
> Any expansion due to heating of the heliax inner should be
compensated by expansion of the linking feeder inner,pushing the
tuning bar upwards.
>
> I have doubts as to the small effect on tuning that 0.2mm
expansion on a 1.3m stub would have (0-40 degC)
>
> I also have doubts that an inner constrained and corrugated in
foam would self expand in the first place.
>
> I think this design could be ideal given some R&D time and a
little patience..I have my eyes on a 25m piece of 1 5/8" at the
moment in the Oxford area.. I just need to persuade
> the owners that I am not a scrap metal capitalist and need the
stuff for a genuine non-profit purpose..
> will keep you posted
>
> Ian
> G8PWE
> Walsall UK
>
> ----- Original Message -----
> From: dave_g7uzn
> To: Repeater-Builder@yahoogroups.com
> Sent: Thursday, December 14, 2006 3:37 PM
> Subject: [Repeater-Builder] Re: 6M duplexer wanted in UK
>
>
> Are you saying that a duplexer built from heliax can cope with a
> 0.5MHz plit at any temperature?....I somehow doubt it (no invar!)
>
> Cheers Dave UZN
>
> --- In Repeater-Builder@yahoogroups.com, "Matt Beasant" <g4rky@>
> wrote:
> >
> > Hi Steve,
> >
> > The 'FH duplexer was built by a very good friend, who doesn't
want
> to build another one!!!
> >
> > But yes, it was built from LDF7-50 1 -5/8" Heliax.
> >
> > Matt
> > ----- Original Message -----
> > From: Steve
> > To: Repeater-Builder@yahoogroups.com
> > Sent: Wednesday, December 06, 2006 5:14 PM
> > Subject: Re: [Repeater-Builder] 6M duplexer wanted in UK
> >
> >
> > Hi Matt
> >
> > What size heliax did you use, I seem to remember that it was
> built for you, wasn't it. I tried myself with small dia stuff
> > and it was not very good, went slightly off tune and of course
> > rx desense. As I have said, itmay just have been the cable I
> used.
> >
> > 73
> >
> > Steve
> > ----- Original Message -----
> > From: Matt Beasant
> > To: Repeater-Builder@yahoogroups.com
> > Sent: Wednesday, December 06, 2006 4:06 PM
> > Subject: Re: [Repeater-Builder] 6M duplexer wanted in UK
> >
> >
> > My heliax duplexer has been in service now for over 2
> > years at GB3FH without fault or need to re-adjust.
> >
> > I check it every time I visit site and it never moves!
> >
> > Over 85dB rejection on one side and 90 odd dB on the
> > other, works fine for me.
> >
> > You can see pictures of it at www.gb3fh.org.uk
> >
> > Regards,
> >
> > Matt, G4RKY
> > --- Steve <steve.m1swb@> wrote:
> >
> > > Hi
> > >
> > > don't get me wrong, Iam not condeming heliax
> > > duplexers
> > > totaly, but you have to take into account
> > > reliability once on site. I did make one but had to
> > > scrap it as it was so unreliable causing de sense
> > > etc, and every time I had to look at it I had to
> > > make arragements to access the site, which could
> > > take upto 2 weeks, must point out the one I
> > > made used small dia heliax, maybe larger dia would
> > > be OK
> > > but as I can't get any, I don't know
> > > Anyway had my say so end of thread from me
> > >
> > > Steve
> > > ----- Original Message -----
> > > From: Barry C'
> > > To: Repeater-Builder@yahoogroups.com
> > > Sent: Wednesday, December 06, 2006 11:25 AM
> > > Subject: Re: [Repeater-Builder] 6M duplexer wanted
> > > in UK
> > >
> > >
> > >
> > > Being a fan to the exclusion of saving several
> > > hundred quid is rather silly
> > > when the duplexers work well and are generally
> > > quite efficient .
> > >
> > > >From: "Steve" <steve.m1swb@>
> > > >Reply-To: Repeater-Builder@yahoogroups.com
> > > >To: <Repeater-Builder@yahoogroups.com>
> > > >Subject: Re: [Repeater-Builder] 6M duplexer
> > > wanted in UK
> > > >Date: Wed, 6 Dec 2006 11:07:54 -0000
> > > >
> > > >Hi
> > > >
> > > > think you will find that Dave, like me, isn't a
> > > huge fan
> > > >of Heliax duplexers, see my posts about actualy
> > > getting
> > > >hold of ldf 750
> > > >
> > > >73
> > > >
> > > >Steve
> > > > ----- Original Message -----
> > > > From: Mr John Lloyd
> > > > To: dave_g7uzn@ ;
> > > repeater-builder@yahoogroups.com ; John
> > > >Lloyd
> > > > Sent: Wednesday, December 06, 2006 6:56 AM
> > > > Subject: [Repeater-Builder] 6M duplexer wanted
> > > in UK
> > > >
> > > >
> > > > Dave,
> > > >
> > > > You can build your own 6 Mtr duplexer. Find some
> > > 1-5/8
> > > > heliax and put one together.
> > > >
> > > > Look at http://www.wa7x.com/ki7dx_rpt.html
> > > >
> > > > Thanks,
> > > >
> > > > John, K7JL
> > > >
> > > > Utah VHF Society
> > > >
> > > > http://utahvhfs.org/snowlink.html
> > > >
> > > > 1a. 6M duplexer wanted in UK
> > > > Posted by: "dave_g7uzn" dave_g7uzn@
> > > > dave_g7uzn
> > > > Date: Tue Dec 5, 2006 3:20 am ((PST))
> > > >
> > > > Hi All, Is anyone with a set of cavity filters
> > > > suitable for 50/51MHz
> > > > brave enough to sell them to me and get them
> > > shipped
> > > > to the UK for a
> > > > 6M repeater project? ALL expences will of course
> > > be
> > > > covered. If you
> > > > can help please email me direct at
> > > >
> > > > dave_g7uzn@
> > > >
> > > >
> > >
> > __________________________________________________________
> > > > Need a quick answer? Get one in minutes from
> > > people who know.
> > > > Ask your question on www.Answers.yahoo.com
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >----------------------------------------------------------
> > > >
> > > >
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> > > > Version: 7.5.432 / Virus Database: 268.15.9/573
> > > - Release Date:
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> > >
> > >
> > >
> > __________________________________________________________
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> > >
> > >
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> >
> > __________________________________________________________
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> >
>
