[TenTec] OT: Question about TS-590 possible problem

Bob McGraw - K4TAX RMcGraw at Blomand.net
Sun Oct 7 11:52:07 EDT 2012

If the noise is broadband then it passes through the bandpass filters.  I've 
found that notch type filters are typically more selective but more 
difficult to use.  Thus is the better approach to use bandpass filters or 
band reject filters?   If one plans to use 2 radios on the same band and 
each employees a bandpass filter then the filters are not effective for 
either radio as the filters pass frequencies within that band, both on 
transmit and receive.

Ideally the effective use of bandpass filters must have the ability of the 
filter to select a very narrow frequency range.  Thus one filter tuned 
exclusively for the CW portion and another filter tuned exclusively for the 
SSB portion of the band.  As one implements filters of higher selectivity 
the insertion loss, both ways, usually increases.  Usually not a problem on 
receive as most receivers have more than adequate gain.  However a 3 dB loss 
on transmit is a lot of power and heat to be dissipated via the filter, not 
to mention only 1/2 of the power getting to the antenna.  Bummer!  Notch 
type filters are typically sharper with less insertion loss but require 
judicious operator involvement.

Choice of radios is very important when one plans to operate two or more 
radios in close physical proximity and specially on the same band.  Then one 
must consider antenna location and orientation.  There are many of the 
current brands and models that will not perform well in "mixed company" 
although they may be excellent "solo" radios.

Bob, K4TAX

----- Original Message ----- 
From: "Rick - DJ0IP / NJ0IP" <Rick at DJ0IP.de>
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
Sent: Sunday, October 07, 2012 3:10 AM
Subject: Re: [TenTec] OT: Question about TS-590 possible problem

> Guys, I am thankful for every attempt to help, but..
> They are either ICE or Dunestar, I didn't ask them which.
> They have not tried stubs yet.
> Besides, even without bandpass filters, good radios do not transmit
> broadband noise that wipes out all other bands.
> I was team contesting long before I purchased two complete sets of 
> dunestar
> BPFs (15 years ago).
> We could run 2 or 3 radios (especially Ten-Tecs) out of the same room with
> antennas in close proximity of each other and the only interference was
> harmonic related.
> We have a lot of experience in team contesting and understand the
> technologies required there.
> This is from our own experience, not from reading books.
> We are simply asking for experience with the TS-590.
> I'm thinking the TS-590 is a random noise generator!
> After receiving information I have received (off-reflector) I honestly
> believe that.
> In the meantime the boys have organized a K2 and TS-850 and will repeat 
> the
> test.
> Soon we will see if it's the radios.
> I'll report what we find out.
> Thanks anyway for all contributions on the topic of 590 and noise
> generation.
> 73
> Rick, DJ0IP
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Don Jones
> Sent: Sunday, October 07, 2012 4:56 AM
> To: 'Discussion of Ten-Tec Equipment'
> Subject: Re: [TenTec] OT: Question about TS-590 possible problem
> I am thinking that if these guys who are having trouble were to add a set 
> of
> BP filters it would go a long ways towards keeping the front ends of the
> radios from going into gain compression.
> Plus if the transmitters are dirty the filters will attenuate noise on the
> other bands.
> I was reading the contesting section of the ON4UN low band DX'ing book and
> see that a pair of 1/4 wave stubs separated by a 1/4 wave of coax makes 
> for
> a highly effective bandpas filter. If they have 3 spare 1/4 sections of
> RG213 for 20M they could fabricate a very effective bandpass filter.
> Bandpass filters are standard fair for SO2R stations - same goes for
> Multi-two contest stations. Not sure if these guys have considered
> fabricating a tri-plexer based upon the QST article. I have built two of
> them and they work great. Sounds like they need a little mentoring 
> regarding
> contest band plans and asset allocation for successful contesting. One 
> note
> on band plans, 10M and 20M do not play well together. The second harmonic 
> of
> 20M will come thru loud and clear on 10M. But then if 10M is open, 15M 
> will
> be too. So drop 20 and go to 10. Basically the 15M station stays put and 
> the
> 20M station picks up 10M if it opens.
> So where are they going?
> 73, Don KO7i
> On 10/5/2012 12:43 PM, Rick - DJ0IP / NJ0IP wrote:
>> A couple of my friends are preparing for an expedition for CQWW and
>> are
> testing their config.
>> They have 2x TS-590 transceivers and a pair of yagi antennas in close
> proximity of each other (about 75' apart).
>> The problem, they are seeing a broadband noise as soon as they key one
>> of
> the transceivers.
>> Even with just 5w of power it is wiping out the other rig on all bands.
>> My old grey cells seem to remember we discussed this here on the
>> Ten-Tec
> reflector about 6 months ago or so.
>> Does anyone remember the details of this or do I have my wires totally
> crossed?
>> Was there a fix or have I dreamt this up?
>> TNX guys, and sorry to spam the group, but if we can get these guys
>> fixed,
> we'll have a nice multiplier in CQWW.
>> 73
>> Rick, DJ0IP
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