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| Ron Stone, GW3YDX - EMail ron@gw3ydx.demon.co.uk
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Hi there Chaps
What shall I do about tribander stacking ? I've already decided that
the Dunestar stack match is the way to go and Ron is appointing me as
EU distributor for the product. Guess it is a good idea to use one
myself too !!!
I'm already the UK agent for Force 12 and KLM antennas and may well be
taking a HyGain dealership soon. Needless to say I have to use one of
those manufacturers products - but which. Some time ago I had a C-3
and a TH7 up on different towers 150 ft apart and at the same height.
The C-3 was always as strong as the TH7 on 20 but did not have a very
good front to back (an advantage to pick up mults ?). I never was able
to do much in the way of comparisons on 15 and 10 because of grot
condx. Intuitively all those elements on the TH7 should work better
- but how do we explain equality on 20m in tests ?
Intuitively (wish I had better to go on) I think the KT34XA I now have
up gets out better than the TH7. Not had a chance of a C-3 versus
KT34XA test. One just runs out of time.
So - what's it to be (at 110 and 75 ft) C-3's - TH7's or KT34XA's -
What do you do ?
Replies (from people with tribander stacks please !) most welcome.
73
Ron
>From sellington" <sellington@mail.ssec.wisc.edu Fri Jul 28 15:52:52 1995
From: sellington" <sellington@mail.ssec.wisc.edu (sellington)
Subject: Filters from In'tl Radio & Computer
Message-ID: <n1405197266.23883@mail.ssec.wisc.edu>
Before going to all the trouble of trying to get filters from IRC, be
sure to compare the specs to those of the manufacturer's filters. While
some of the IRC SSB filters may provide a significant improvement, most
of their CW filter specs are nearly identical to Kenwood's, ICOM's, etc.
The standard filters can usually be had quickly, for not much more
money than IRC's. Whether there is a difference in the CW filters beyond
the specs, I can't say. However, the shape factors for the Kenwood 500
Hz and 250 Hz filters in my TS-930 meet both the Kenwood and IRC specs.
Scott K9MA
sellington@ssec.wisc.edu
>From Tony Brock-Fisher <fisher@hp-and.an.hp.com> Fri Jul 28 16:28:30 1995
From: Tony Brock-Fisher <fisher@hp-and.an.hp.com> (Tony Brock-Fisher)
Subject: Filters from In'tl Radio & Computer
Message-ID: <9507281528.AA07232@hp-and.an.hp.com>
IRC filters may be the same in shape factor, but I think they
are usually at least 10 db better in 'blow-by' - which is
ultimate rejection out of the passband. This is an area where
most of the cheaper rigs suffer because of the use of ceramic
filters. (430, 440, 735, etc).
-Tony, K1KP, fisher@hp-and.an.hp.com
>From H. Ward Silver" <hwardsil@seattleu.edu Fri Jul 28 16:39:55 1995
From: H. Ward Silver" <hwardsil@seattleu.edu (H. Ward Silver)
Subject: Responses to QRQ Help Request
Message-ID: <Pine.3.07.9507280853.D23174-a100000@bach.seattleu.edu>
I just remembered a neat item from the W6AM biography (worth a read) as to
how Don got to be so fast on CW. Seems he was stationed on one of the San
Francisco Bay lighthouse-ships with another guy (maybe it was an
island...I forget). At any rate, they had nothing else to do, so they
played "burnout", which entailed sending to each other faster and faster
until the other guy could no longer keep up. I would not particularly
care to be in a "burnout" contest with W6AM, but I can see how my code
speed might improve some ;-)
73, Ward N0AX
>From sellington" <sellington@mail.ssec.wisc.edu Fri Jul 28 16:41:21 1995
From: sellington" <sellington@mail.ssec.wisc.edu (sellington)
Subject: Filters from In'tl Radio & Computer
Message-ID: <n1405194380.98176@mail.ssec.wisc.edu>
K1KP writes:
>IRC filters may be the same in shape factor, but I think they
>are usually at least 10 db better in 'blow-by' - which is
>ultimate rejection out of the passband. This is an area where
>most of the cheaper rigs suffer because of the use of ceramic
>filters. (430, 440, 735, etc).
The ceramic filters generally have poor shape factors, as well. However,
the rigs with a single IF filter are more likely to suffer the "blow-by"
problem, in which case the IRC filters may offer some improvement. Those
with filters at two IF's, like the 930/940 etc., don't require filters
with such high ultimate rejection because the two filters are cascaded.
A single filter with 70 dB of ultimate rejection will produce noticable
response to out-of-passband signals, while two such filters giving 140 dB
of rejection won't respond to much outside the passband. So, improving
the ultimate rejection of the filter in the first case may be useful.
Scott K9MA
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