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G8MNY  > TECHNI   02.10.21 11:00l 103 Lines 5335 Bytes #999 (0) @ WW
BID : 48434_GB7CIP
Read: GUEST
Subj: My Home HF Set-up
Path: PI8DRE<PI8CDR<LU4ECL<GB7CIP
Sent: 211002/0858Z @:GB7CIP.#32.GBR.EURO #:48434 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                               (Updated May 21)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
After several years of HF improvements, I have ended up with this....
        ___
 LS<컴캑BHI쳐<DC                    旼컴컴컴컴컴컴컴컴컴컴컴<20ft Noise Aerial
12cm   쿏SP쳐컴컴          PTT                             in front Garden
       읕컴   LS  旼컴컴컴컴컴컴컴)커旼PA FAN  _______
     ______   ____      _________  납 _____         쳐1KW PEP Dummy Load
Mic>퀮uto  쳐퀹COM 쵬 DC>퀿oise    쵬 읒큈500M 쿛alstar쳐40m Delta loop
   渼caller 쿔C735쳐컴컴퀰anceller쳐컴캑 HF  쳐퀮T1500 쳐>80/40/20/10 Dipoles
H/P냅컴컴컴  RIG 쳐컴 읕컴컴컴컴 旼캑 PA     ATU  ())袴袴袴>160m Dipole
            읕컫컴   읕컴컴컴컴컴컴  읕컫컴 읕컴쩡컴 쩡       back Garden
             DC ___       ALC      _____ 13.8v  __     RF
               윱PSU              쿞MPSU쵬      ////    쿞niff
            DC<캑25A쳐<M            75A 쳐<M            
   쿧1           읕컴              읕컴컴               
  ____ Y2                                                    旼컴컴커
 쿞COPE쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴켸 M<캑Filter<Mains
 _____쳐<M                                                    읕컴컴켸

FEATURES
PSU Homemade Linear type, with 3A trip for low current leads, & a mains filter.
SMPSU converted DEL Server PSU, with thick PA DC leads, & Ferrite rings.
BHI DSP LS gives 10-20dB of noise reduction (ignors noise), used with large LS.
Noise Canceller JPS ANC-4 with aerial, gives >15dB of QRM nulling on 1 source.
IC735 sometimes used with its effective tuneable Noise Blanker or Attenuator.
Auto caller Home-made CQ repeating & off air record & playback.
IC735 used with it's very effective AF processor (10dB clipper) & standard Mic.
T500M PA draws 75A @ 13.8V, so use SMPSU or float a car batts with thick leads.
My T500A ALC ensures the Amp can't be over driven even on 11V DC or a bad SWR.
Palstar AT1500CV ATU, cross needed power, handles high SWRs & can be balanced.
Dummy load with PEP meter gives accurate PEP power measurments (scope option).
Scope for monitoring Tx envelope & Rx AF Noise (timebase locked to mains).
Mains filter adaptors, both include earth chokes.

ON AIR
I often get comments on how good the AF is (especially under noisy band
conditions), it is just a well set up standard AF clipper (compressor) about
10dB (3x) on the IC735 with it's toppy AF, do not clip bassy AF! The Tx filter
bandwidth is 2.4kHz (300Hz-2.7kHz), but it does not suit all ears & in strong
signal QSOs, I then turn compresser off. And I always use close up mic, to
reduced background noise & room echo, & keep the ALC drive level correct.

The PA helps a lot, & when I go back to QRP stations M6s etc, & run their QRP,
they often can't hear me, or would not have called me with a weak QRP signal.

I have had very complementary reports on how clean (narrow) the QRO signal is.
E.g. "-35dB down on adjacent ch" & "You are much stronger than me at remote WEB
SDR Rx site & also narrower!" So the old IC735 rig with its comms quality audio
fixed narrow Tx IF, & the older 1977 Commercial PA with high levels of NFB, &
my PA's ALC circuit, keep the Tx signal all very clean.

My Autocaller CQ, keeps the channel busy, while I catch up with paper log, or
get the perfect SWR etc. & then I get called. But its CQ calls are bit noisy
especially into the rigs clipper (10dB S/N lost). Overall it does make for lazy
operating with less scanning. I do use 2nd VFO for that & go back to my CQ VFO.

The 3 noise systems I use,
1/ JPS ANC-4 Noise Canceller (null steerer), 2/ rig's tuneable Noise Blanker,
& 3/ BHI DSP noise ignoring LS. These all complement each other very well, as
they work differently. Sometimes all 3 are needed to get a usable band here, in
RF noisy Croydon. With the JPS ANC-4, do not Rx too much Tx power on the noise
aerial, as it can be damaged with nearby QRO! Using seperated aerials as I do,
stops this, & also helps get deep nulls while leaving Rx signals, with same
location aerials you tend to null out all signals at once!

The Scope timebase is locked to mains, & both beams are added to give just 1
line. Rx AF can help adjust the Noise Canceller & rig Noise Blanker threshold,
as you can see the offending neighbours SMPSUs, & null out one pair of 100Hz
noises, but not if 2 or more appear on another mains phases. Not mains locked
QRM from TV/PC screens, polling data, PLTs systems, can be seen, & other non
ham things like over the horizon radar "Wood Pecker" or "QRO 50Hz FM sweep
jammers" are easily identifed too.

The Tx envelope display shows up the peak with or without compression, all
nicely rounded peaks under ALC power control, with no hard clipped wideband
splattering flat tops!


See all these related TECH buls....
"Autocaller with old Maplin kit"
"High AMP Crowbar Protected PSU"
"DEL 7000815 SMPSU 12V 75A Mods"
"T500M 12V 500W HF Linear"
"Variable Speed Thermal Fan"
"BHI Noise Eliminating DSP LS"
"IC 735 No RF Output Fault"
"Palstar AT1500CV ATU"
"QRO 1kW HF Metered Dummy Load"
"A Nest of Dipoles for HF"
"Mains Plugtop Filter Adapter"
"Oscilloscopes"
"AF 2 Tone Test Osc Design"
"QRO v QRP".


Why Don't U send an interesting bul?

73 de John G8MNY @ GB7CIP


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