Bob,
Indeed, 40m is the main band where needed, unless of course the transceiver
is participating as one of the radios in a multi-multi station - in which
case you need this for all bands.
The problem here is not caused by one station. It is caused by a multitude
of stations broadcasting in the 41m and 39m bands. 41m begins at 7200 kHz
and Radio China pegs most S-meters. The 49m band ends at 6200 kHz.
Sinisa was right, the BPFs made for transmitters really aren't good enough.
You do need a good preselector.
I have not tried the MJF preselector and don't know if it is good enough or
not.
There are some really good preselectors on the used market, such as those
made by Braun, but they sell for just as much or more now, then they did
when new 20 years ago. Supply and demand.
3 years ago, Ten-Tec was considering to bring out a high performance
preselector. I discussed this with Jack Burchfield and John Henry. They
thought it would retail for (as I recall) about $800, which in today's
currency is probably what the Brauns cost. I didn't think they could ever
recover their investment and they didn't think they could build it much
cheaper so the project was scrapped.
John Henry can supply more details if he's monitoring this thread.
Coax stubs work great for taking out single stations. I don't know how well
they work for taking out a range of frequencies. Maybe "good enough". In
that case, one for the 49m and one for the 41m bands might be enough and a
lot cheaper than a good preselector.
73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Katz Ajamas
Sent: Tuesday, September 13, 2016 5:23 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Scads of used Icom IC-7300
Dr Rick-
I am only saying that the 7300 has a band pass filter covering the 40m band.
It is a bit wider(6500-8000kHz) than the band. If it's too wide for the
conditions, a pre-selector is one solution. If it is adequate for the
conditions, there is no need for a pre-selector. If the MFJ pre-selector
does the job, there is no need to wait for someone to introduce a better
one. I have only heard you mention problems on 40m. Why would we need
dedicated filters for every ham band? Perhaps if we want a multi transmitter
contest grade radio for $1400. For 40m, one of the $100 filters you mention
or trap(s) for the offending nearby station(s) will make 40m front end
filtering at least as good as the 6500. Here, I use a trap with 160m because
of a 5kW station on 1690kHz that is <2km from my QTH and has a
3 ele phased array in my direction!
As I said earlier, I will not be buying a 7300. Primarily because the DSP is
not set up for weak signal CW. If I were to buy another 100W HF rig, it
would be another Eagle or maybe a TS590SG. The 7300 Hysteria will need to
drive the used price down a bit more.
73, -Bob
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