I ought to sue.
K1JX
>From oo7@astro.as.utexas.edu (Derek Wills) Thu Aug 17 04:19:40 1995
From: oo7@astro.as.utexas.edu (Derek Wills) (Derek Wills)
Subject: Return of the Octopus
>>I ought to sue. K1JX
Don't do that, lawyers charge you an arm and a leg.
Or this case, eight of 'em...
Sorry - Derek AA5BT, G3NMX
oo7@astro.as.utexas.edu
>From J.P. Kleinhaus" <aa2du@netcom.com Thu Aug 17 05:34:55 1995
From: J.P. Kleinhaus" <aa2du@netcom.com (J.P. Kleinhaus)
Subject: new rigs
Message-ID: <Pine.3.89.9508162145.A11344-0100000@netcom3>
I find it hard to believe that Yaesu would
put on a show of describing "Collins Mechanical Filters"
if they indeed had DSP in the IF. It is my understanding
that IF DSP replaces mechanical or crystal filters in
a DSP radio. The Icom and Yaesu implementations are
not true DSP radios in that sense. They still require
standard filters...the DSP is indeed nothing
fancier than a Timewave or W9GR unit in the AF stage.
The forthcoming Kenwood rigs are TRUE IF DSP, with no
other filters necessary...I heard one on the air the
other day annd it sounded fine. One of the design
engineers happens to live noet too far from here, and I
hope to get a listen to the receiver in the near future.
73, J.P. AA2DU
*******************
J.P. Kleinhaus, AA2DU
ARRL Hudson Division C.A.C. Representative
E-mail: aa2du@netcom.com
aa2du@aa2du.slip.netcom.com
Compu$erve: 74660,2606
TVI?? What TVI??!
*********************************************************************
On Wed, 16 Aug 1995, scotty neustadter wrote:
> >To: Srockn4sr@aol.com
> >From: scotty@iquest.com (scotty neustadter)
> >Subject: Re: new rigs
> >
> >>Hi All
> >>
> >>Reading the fine print on the description of both the new yaesu and icom
> >>radios leads me to believe that both of these radios are using DSP
> >>techniques
> >>in the AUDIO sections only. Basically a timewave DSP unit added onto the
> >>radio. I have from a reliable source that the new Kenwood uses DSP in the
> >>IF
> >>section. Might be a good idea to hold off on buying that new wiz bang radio
> >>till you see what all the mfgr's have to offer.
> >>73 steve
> >>
> >>
> >Yaesu Rig DSP is in the IF section per Kevin Karamanos, Yaesu Sales Manager
> >
> Scotty Neustadter, N4PYD
> President, North Alabama DX Club
> Huntsville Hamfest Chairman
> Internet: scotty@iquest.com
> MCI Mail: N4PYD Fax: 205 880 9530
> Nothing is more fairly distributed than common sense: no one thinks he
> needs more of it than he already has. --Descartes
>
>
>From Takao KUMAGAI <je1cka@dumpty.nal.go.jp> Thu Aug 17 07:39:32 1995
From: Takao KUMAGAI <je1cka@dumpty.nal.go.jp> (Takao KUMAGAI)
Subject: [cq-contest 7428] Re: VPED and PED files / 16 bit soundblaster bug
Message-ID: <199508170639.PAA25822@dumpty.nal.go.jp>
on 95/08/16, Tony and Celia Becker writes:
: The one bug reported with VPED is that it does not record from the 16 bit
: soundblaster.
Is this true?
When Mas started to program the VPED, I sent the all the informations
which came with SB16ASP to Mas. And my version worked (I did not play
it over a year or so) fine with SB16ASP.
I believe Randy K5ZD played VPED with my computer which had SB16ASP
at HamFair in last Aug. The vped sound file was created by Saty JE1JKL
at that morning.
Anyway, I'll check it and report later.
---------
Tack Kumagai JE1CKA/KH0AM
TEL:81-30-066-6408, FAX:81-423-93-4449
Internet: je1cka@nal.go.jp
>From Marijan Miletic <s56a@ljutcp.hamradio.si> Thu Aug 17 08:11:21 1995
From: Marijan Miletic <s56a@ljutcp.hamradio.si> (Marijan Miletic)
Subject: True DSP
Message-ID: <73137@ljutcp.hamradio.si>
Recent rumours about TS-870 seem to signal the arrival of TRUE DSP ham radio
transceiver. It should be noted that present top class rigs like TS-950,
IC-775 and forthcoming FT-1000MP use AF DSP also for transmission which should
improve SSB signal quality and even save on expensive RF cliping which requires
dual SSB filters. The main advantage of IF DSP is the actual cost cutting on
good filters BUT do NOT expect DSP IF filters to be SO much better than good
old "Collins" mechanical one. Out of band rejection and large signal handling
is definitely better with analog technique. Digital AGC also needs a lot of
attention as witnessed by QST review of early model HF-1000 "made in USA" RX.
I am glad I postponed purchase of my new HF xcvr and I am looking forward to
the tech reviews of real "new technology" (This does NOT include separate key
and RX antenna input, transverter support, switching power supply etc).
73 de Mario, S56A, N1YU.
>From steve.wilson@almac.co.uk (STEVE WILSON) Thu Aug 17 08:07:00 1995
From: steve.wilson@almac.co.uk (STEVE WILSON) (STEVE WILSON)
Subject: New Kenwood TS-870S 3
Message-ID: <8AF51E7.1412003F09.uuout@almac.co.uk>
(Continued from previous message)
Dimensions (WxHxD) 13 x 4.7 x 13.1 inches
[excluding protrusions] 330 x 120 x 334 mm
Weight 25 lb [11kg]
Frequency Stability +/-10 x 10^6
+/-0.5 x 10^6 (with SO-2)
Antenna Impedance 50 ohms
Circuitry Quad conversion
Intermediate Frequencies 1st 73.05 MHz
2nd 8.83 MHz
3rd 455 kHz
4th 11.308 kHz
Sensitivity SSB, CW, FSK
100 - 500 kHz: less than 1 uV
500 kHz - 1.705 MHz: less than 4 uV
1.705 - 24.5 MHz: less than 0.2 uV
24.5 - 28 MHz: less than 0.13 uV
28 - 30 MHz: less than 0.13 uV
Selectivity
Mode Setting Value -6dB -60dB
---------------------------------------------------------
CW Width 200 Hz 200 Hz 450 Hz
---------------------------------------------------------
SSB Lo: 300 Hz 2300 Hz 3300 Hz
Hi: 2600 Hz
---------------------------------------------------------
FSK Width: 500 Hz 500 Hz 1000 Hz
---------------------------------------------------------
Audio output More than 1.5W (8ohms at 10% distortion)
Digital filter settings:
SSB: High-cut (kHz)
Selectable 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.4, 4.6, 6
SSB: Low-cut (Hz)
Selectable 0, 50, 100, 200, 300, 400, 500, 600, 800, 1000
CW: Bandwidth (Hz)
Selectable 50, 100, 200, 400, 600, 1000
CW: Centre frequency (Hz)
Selectable 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950,
1000
FM: Passband bandwidth (kHz)
Selectable 5, 6, 8, 10, 12, 14
FSK: Bandwidth (Hz)
Selectable 250, 500, 1000, 1500
[TRANSMITTER]
RF Power Output 100W (SSB, CW, FSK & FM)
25W (AM)
Unwanted sideband suppression More than 50dB
Carrier suppression More than 50dB
Spurious response Less than -50dB
Auto antenna tuner matching range 20 - 150 ohms
The rig appears to have analogue metering from the picture on the FAX.
73 de Steve, G3VMW
Steve Wilson
* 1st 2.00o #6466 * It takes courage to innovate, not imitate.
>From steve.wilson@almac.co.uk (STEVE WILSON) Thu Aug 17 08:07:00 1995
From: steve.wilson@almac.co.uk (STEVE WILSON) (STEVE WILSON)
Subject: New Kenwood TS-870S 2
Message-ID: <8AF51E7.1412003F08.uuout@almac.co.uk>
(Continued from previous message)
Thanks to DSP technology, the quality of signal detection is better
than possible with conventional transceivers in terms of both low
distortion and high sound quality.
2. High Speed PC control
Using a PC, it is possible to control at high speed every TS-870S
function, including power on/off. When the RS-232C connector on the
rear panel is hooked into a computer, data speeds of 57600 bps are
possible.
Models sold in the USA/Canada are supplied with control software (for
use with Windows 3.1)
3. Automatic Antenna Tuner that works on both TX and RX
The built-in antenna tuner, which is preset to cover amateur bands in
the range of 1.8 to to 28 MHz enables rapid tuning. It is also
possible during RX to pass the signal to the automatic antenna tuner.
4. Full Range of features for CW operation
(a) Built-in multi-functional electronic keyer
The TS-870S has a 4-channel message memory for its multi-functional
electronic keyer, which is based on the K1 Logikey.
(b) Full break-in and semi break-in (selectable)
(c) Two key connectors (on the rear panel)
(d) CW pitch control
The user can control the pitch between 400 Hz and 1000 Hz in 50 Hz
steps.
(e) Selectable leading & trailing edge for CW waveform
The user can choose values of 2ms, 4ms, 6ms and 8ms for the leading
edge (key down) and trailing edge (key up).
5. DRU-3 digital recording unit (option)
By adding the DRU-3 unit, up to 60 seconds of continuous digital
recording is possible.
6. 100 memory channels
In addition to 99 channels available as split memory, 1 channel is
set aside for programmable VFO and programmable scan use.
7. Multiple scan functions
(a) Memory scan
The user can choose between scanning all memory channels with data,
and scanning groups of 10 channels
(b) Channel lock out
Unwanted channels can be skipped during scanning
(c) Programmable scan
8. Menu system
The TS-870S is designed to simplify front-panel operation to ensure
user convenience, and this includes the 68-item menu system which
enables the user to adjust various settings with ease. The user can
switch between A and B menus. The contents of each menu will be
displayed on the alpha-numeric sub-display.
9. Programmable function keys
Four keys surrounding the tuning knob can be used as programmable
function (PF) keys. Each can be assigned a specific menu function.
10. TX AGC
Automatic Gain Control ensures that however much the audio level
changes, the modulation of the TX signal is constant. TX AGC
performs just the right control for SSB, FM and AM modes.
Specifications (tentative)
[GENERAL]
Operating Frequency Range RX: 0.1 - 30 MHz
TX: 1.8 - 30 MHz (Amateur bands only)
Modes SSB, CW, FSK, AM & FM
Operating Temperature -10 to +50 degrees C
Input Voltage DC 13.8V +/- 15%
Current Drain RX: 2A (no signal)
TX: 20.5 A (max. transmit)
(Continued to next message)
* 1st 2.00o #6466 * It takes courage to innovate, not imitate.
>From steve.wilson@almac.co.uk (STEVE WILSON) Thu Aug 17 08:07:00 1995
From: steve.wilson@almac.co.uk (STEVE WILSON) (STEVE WILSON)
Subject: New Kenwood TS-870S 1
Message-ID: <8AF51E7.1412003F07.uuout@almac.co.uk>
I had some information about the new TS-870S transceiver FAXed to me
last night and I figured it might be of interest. I know nothing more
than I've shared with you here and I have no connection with Kenwood,
except for owning a TS-930S and a TS-950SDX. So guys - please don't
shoot the messenger.
This radio looks interesting for contesting & DXing!
New Products Preliminary Information TS-870S
--------------------------------------------
To: All Kenwood Distributors
By supplying the best of its DSP technology, Kenwood has succeeded in
developing the TS-870S, a new generation of HF SSB transceiver that
offers superior digital interference reduction as well as receiver
performance quality hitherto impossible using conventional analogue
circuitry. New HF transceivers based on this design concept are
collectively called the "Intelligent Digital Enhanced Communication
System".
Schedule:
---------
Production August
Shipment September
Leaflet August
* This schedule is for the wide step version. The schedule for the
narrow step version will be announced when available.
Main Features
-------------
1. High Frequency DSP for IF signal processing
The TS-870 features IF digital filters for all modes - SSB, CW, AM, FSK
and FM - a world first - offering precise performance that is
unobtainable with analogue circuits. Bandwidth of the digital filters
can be optimized in various working conditions. You are also free from
struggling to install optional IF filters, thanks to the new razor sharp
digital filters.
(a) Digital RX Filters
SSB Mode Hi-cut 1.4 - 6.0 kHz (12 steps)
Low-cut 0 - 1.0 kHz (10 steps)
CW Mode VBT 50 - 1000 Hz (6 steps)
SHIFT 400 - 1000 Hz (13 steps)
FM Mode VBT 5 - 14 kHz (6 steps)
AM Mode Hi-cut 2.5 - 7 kHz (6 steps)
Low-cut 0 - 500 Hz (4 steps)
FSK Mode VBT 250 - 1500 Hz (4 steps)
(b) Noise Reduction
The TS-870S is capable of picking out a target signal that is buried
in noise. To accomplish this, it employs the line enhancer method
for SSB mode and SPAC method for CW mode.
(c) Beat cancel
This cancels out the sort of multiple beat interference that can
affect reception automatically, which is impossible for analogue
circuits.
(d) IF Auto-Notch
This is a filter which, when beat interference is experienced,
attenuates only the interfering signal. Should the frequency change,
the filter adjusts automatically. Thanks to the IF DSP, it offers
more precise performance than previously possible.
(e) Selectable TX audio quality & characteristics
3 types of adjustment are possible:
* TX characteristic adjustment
In SSB & AM modes, the bandwidth of the bandpass filter can be
controlled.
* Band-division speech processor
The speech processor can be adjusted separately for low, medium
and high ranges.
* TX equalizers
Equipped with three equalizers - high boost, bass boost, and comb
filter. The TS-870S allows the user to select the desired sound
quality.
(f) DSP signal detection
(Continued to next message)
* 1st 2.00o #6466 * It takes courage to innovate, not imitate.
>From Ed Gilbert <eyg@hpnjlc.njd.hp.com> Thu Aug 17 13:26:32 1995
From: Ed Gilbert <eyg@hpnjlc.njd.hp.com> (Ed Gilbert)
Subject: new rigs
Message-ID: <199508171223.AA049752221@hp.com>
> The forthcoming Kenwood rigs are TRUE IF DSP, with no
> other filters necessary...
Of course the arrival of new rigs with wizzy new features is always
exciting, and for the past few years the anticipation for a contest
radio with a digital IF has been great. Whether the new Kenwood 870
is truly the quantum leap in technology that we've been waiting for
remains to be seen. The only clue that I've seen as to its true
architecture is this:
> Circuitry Quad conversion
>
> Intermediate Frequencies 1st 73.05 MHz
> 2nd 8.83 MHz
> 3rd 455 kHz
> 4th 11.308 kHz
The 870 probably has digital filtering in the 4th IF. Does that mean
it doesn't need good sharp crystal lattice filters in the earlier
stages? Anyone who has tried to use the IF shift feature on an
unmodified Icom 765 in a contest knows what happens when you bypass
the filtering in the 2nd IF. Anyone who has used a Drake C-line with
a Sherwood filter in the first IF knows what an improvement it makes.
I wonder what the difference is between audio filtering and filtering
in a 4th IF. The 870 may turn out to be a fine new radio, but I'm not
quite ready to throw out my cascaded, early IF stage crystal lattice
filters.
73,
Ed Gilbert WA2SRQ
eyg@hpnjlc.njd.hp.com
>From Mr. Brett Graham" <bagraham@HK.Super.Net Thu Aug 17 13:24:12 1995
From: Mr. Brett Graham" <bagraham@HK.Super.Net (Mr. Brett Graham)
Subject: Phased Beverages! (was: EVE vs Beverage?) (fwd)
Message-ID: <199508171224.AA01340@is1.hk.super.net>
W3LPL said:
I know other Beverage users have used concrete-filled buckets, perhaps they
will comment on the pros and cons of that approach...
While I haven't had a chance to run beverages into the jungle yet, I have
had some experience with concrete buckets. Until late '93, I used them for
the base of my 6m tower - perfect way to avoid sinking Hiltis into the
roof (which usually ends with one finding the roof slab to be about 20mm
thinner than necessary - oops). I also have used a concrete bucket base
for a 1.25m TVRO dish, though it would go walkabout, sliding around the
roof during typhoons.
My HF2V currently uses a concrete bucket for a base on the roof, though it
is guyed. At the old QTH, the same bucket held an R7 without guys out in
the jungle - all you need to do is drop it into a hole in the ground as
deep as the bucket is tall. The base of the R7 was nearly 2m up & despite
its top-side windage, didn't go anywhere in 110+ km/h winds. Based on
this, a beverage should be a piece of cake. I'd consider this technique
for a beverage at my new QTH, except I doubt it would hold up against the
cows - the bloody things would use it as a scratching post & probably pull
the whole lot down!
73, VS6BrettGraham aka VR2BG bagraham@hk.super.net
>From n4zr@ix.netcom.com (Pete Smith) Thu Aug 17 14:15:29 1995
From: n4zr@ix.netcom.com (Pete Smith) (Pete Smith)
Subject: HF Launch Angles
Message-ID: <199508171315.GAA02438@ix8.ix.netcom.com>
>N4ZR said:
>
> The software Dean uses for measuring the effects of terrain is also
> available, either from the ARRL BBS or from various sites that FTP
> materials from QEX - buffalo.edu is one. It's called YTAD.ZIP.
>
>I tried, but buffalo.edu or ftp.buffalo.edu come back as unknown hosts from
>here. Can somebody tell me what I've got wrong, or another possible site
>to try? Thanks!
>
>73, VS6BrettGraham aka VR2BG bagraham@hk.super.net
Actually, N4ZR screwed up. The actual source is ftp.cs.buffalo.edu in the
/pub/hamradio/qex directory. Dean tells me it is there now. Note that
those are forward slashes for all the Unix fans out there.
73, Pete Smith N4ZR
n4zr@ix.netcom.com *** note new e-mail address ***
Radio Free West Virginia (under construction)
>From Takao KUMAGAI <je1cka@dumpty.nal.go.jp> Thu Aug 17 14:50:48 1995
From: Takao KUMAGAI <je1cka@dumpty.nal.go.jp> (Takao KUMAGAI)
Subject: [cq-contest 7475] YTAD.EXE(Re: HF Launch Angles)
Message-ID: <199508171350.WAA00428@dumpty.nal.go.jp>
Thanks Pete
on 95/08/17, Pete Smith writes:
: Actually, N4ZR screwed up. The actual source is ftp.cs.buffalo.edu in the
: /pub/hamradio/qex directory. Dean tells me it is there now. Note that
But the correct URL is
ftp://ftp.cs.buffalo.edu/pub/ham-radio/qex/ytad.zip
^
The file size is 69k.
---------
Tack Kumagai JE1CKA/KH0AM
TEL:81-30-066-6408, FAX:81-423-93-4449
Internet: je1cka@nal.go.jp
>From Tony Brock-Fisher <fisher@hp-and.an.hp.com> Thu Aug 17 14:51:09 1995
From: Tony Brock-Fisher <fisher@hp-and.an.hp.com> (Tony Brock-Fisher)
Subject: TRUE DSP AT IF
Message-ID: <9508171351.AA26982@hp-and.an.hp.com>
Ed Gilbert writes:
>I wonder what the difference is between audio filtering and filtering
>in a 4th IF. The 870 may turn out to be a fine new radio, but I'm not
>quite ready to throw out my cascaded, early IF stage crystal lattice
>filters.
With respect to this, I'd like to point out that a major advantage would
lie in the fact that the DSP could now be included INSIDE the AGC loop.
With an external DSP box, the DSP rejection is outside of the AGC loop.
This means that even though the DSP can remove a heterodyne from the
audio passband, the signal is still present in the AGC of the recevier.
A strong heterodyne can push the AGC, reducing receiver sensitivity to
the desired signal. If the DSP is inside the AGC loop, it can remove
the offending signal before it has a chance to affect the AGC, thereby
allowing the AGC to properly track the desired signal. Of course this
places increasing dynamic range requirements on the earlier stages.
Of critical importance in a 'true dsp' receiver is the A/D conversion
used; this ultimately establishes the dynamic range of the DSP. The cost
associated with the A/D is probably what has prevented the appearance
of 'true dsp' in ham receivers until now.
-Tony, K1KP, fisher@hp-and.an.hp.com
>From Ingemar.Fogelberg@CEC.Comm.SE (Ingemar Fogelberg) Thu Aug 17 14:59:14
>1995
From: Ingemar.Fogelberg@CEC.Comm.SE (Ingemar Fogelberg) (Ingemar Fogelberg)
Subject: new rigs
Message-ID: <199508171359.AA14145@nic.comm.se>
>> The forthcoming Kenwood rigs are TRUE IF DSP, with no
>> other filters necessary...
>
>Of course the arrival of new rigs with wizzy new features is always
>exciting, and for the past few years the anticipation for a contest
>radio with a digital IF has been great. Whether the new Kenwood 870
>is truly the quantum leap in technology that we've been waiting for
>remains to be seen. The only clue that I've seen as to its true
>architecture is this:
>
>> Circuitry Quad conversion
>>
>> Intermediate Frequencies 1st 73.05 MHz
>> 2nd 8.83 MHz
>> 3rd 455 kHz
>> 4th 11.308 kHz
>
>
>The 870 probably has digital filtering in the 4th IF. Does that mean
>it doesn't need good sharp crystal lattice filters in the earlier
>stages?
--- CUT---
One of the main issues when trying to design a DSP IF is to maintain
the dynamic range of 100 - 110 dB. Thats a lot more than
in a CD-player.
I guess the have thrown in ONE very good XTAL-filter in front of the
A/D-conversion circuit to make the input signal band limited to avoid
aliasing in the DSP. Still you have to use a very good A/D-converter.
One advantage of using DSP at IF -level is that your AGC will work
correct and not trying to put down RX-sensitivity caused by QRM outside
the AF-filter. (An AF-filter is not in the AGC-loop)
But, if KNWD has succeeded with this they probably is going in the right
direction of very sharp CW-filters with no ringing etc.
73 de Ingo/SM0AJV
Ingemar Fogelberg if@cec.comm.se
Communicator CEC AB Phone: +46-8-764 41 94
Box 1310, S-171 25 Solna, Sweden Fax: +46-8-764 45 70
>From k3ww@fast.net (Charles Fulp) Thu Aug 17 15:23:17 1995
From: k3ww@fast.net (Charles Fulp) (Charles Fulp)
Subject: WAE SCORE
Message-ID: <m0sj5sO-0004h7C@nn.fast.net>
Just 7 hours of operation this year, better conditions might have torn
me away from yard and antenna projects, but hit my favorite spots and
times.
415 QSOs 410 QTC 76 Countries and 171,392 points
had 13 QSOS on 15, 39 on 80 191 on 40 and 172 on 20 , Stack phase box
not working after lightning flicker, so used my multiplier chasing
antenna for 20 and 15. 73 Chas K3WW new address k3ww@fast.net
>From junger@mtn.er.usgs.gov (John Unger) Thu Aug 17 15:25:48 1995
From: junger@mtn.er.usgs.gov (John Unger) (John Unger)
Subject: Grounding
Message-ID: <9508171425.AA17322@mtn.er.usgs.gov.er.usgs.gov>
>
> Hi all - I am planning on installing a concrete swimming pool in my yard
> in the near future, and wonder if there would be any use (or danger!) of
> grounding the tower to the pool ground.
Barry - I guess that you missed the "exploding concrete tower base"
discussion here a while back. My guess is that you should just plan
to store live lobsters and shell fish in your pool and then wait for
a thunderstorm -- instant boiled lobster dinner! :-)
Sorry, Barry, but I couldn't resist....
73 - John, W3GOI
>From Lau, Zack, KH6CP" <zlau@arrl.org Thu Aug 17 15:31:00 1995
From: Lau, Zack, KH6CP" <zlau@arrl.org (Lau, Zack, KH6CP)
Subject: True DSP
Message-ID: <3033534D@arrl.org>
---
>dual SSB filters. The main advantage of IF DSP is the actual cost cutting
on
>good filters BUT do NOT expect DSP IF filters to be SO much better than
good
>old "Collins" mechanical one. Out of band rejection and large signal
handling
>is definitely better with analog technique. Digital AGC also needs a lot
of
Measurements I've seen of IMD on mechanical filters indicate 3rd order
dynamic ranges of 90 to 100 dB, which means they may be the limiting
factor in high performance radios.
For really high dynamic ranges, phasing receivers that convert directly
to audio can do really well. My version of the Rick Campbell phasing
receiver in the 1995 ARRL Handbook has a 100 dB two tone DR, despite
the SSB bandwidth and a preamp to reduce the NF to 8 dB. Some
rather expensive commercial gear doesn't do as well. IMD due to
ferrite cores usually isn't a factor, despite the popular literature. Its
too
much work to measure, while crystal filters are easy by comparision.
Zack zlau@arrl.org
|