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G8MNY > TECH 28.11.24 10:30z 105 Lines 5398 Bytes #157 (0) @ WW
BID : 20727_GB7CIP
Read: GUEST
Subj: My Home HF Set-up
Path: SR1BSZ<IW0QNL<JH4XSY<JE7YGF<LU4ECL<I0OJJ<UA6ADV<CX2SA<GB7CIP
Sent: 241128/1021Z @:GB7CIP.#32.GBR.EURO #:20727 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Jul 24)
(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<ÄÄÄ´BHIÃÄ<DC ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ<20ft Noise Aerial
12cm ³DSPÃÄÄÄÄÄ¿ PTT ³ in front Garden
ÀÄÄÄÙ LS³ ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ)Ä¿ÚÄPA FAN _______
______ ___³_ ³ _________ ³ ³³ _____ ³ ÃÄ1KW PEP Dummy Load
Mic>´Auto ÃÄ´ICOM ÃÙ DC>´JPS NoiseÃÙ ÀÁ´T500M³ ³PalstarÃÄ40m Delta loop
Ú´caller³ ³IC735ÃÄÄÄÄÄ´CancellerÃÄÄÄÄ´ HF ÃÄ´AT1500 ÃÄ>80/40/20/10 Dipoles
H/P³ÀÄÄÄÄÄÄÙ ³ RIG ÃÄÄÄ¿ ÀÄÄÄÄÄÄÄÄÄÙ ÚÄÄ´ PA ³ ³ ATU Æ())ÍÍÍÍÍÍ>160m Dipole
³ ÀÄÄÂÄÄÙ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ÀÄÄÂÄÄÙ ÀÄÄÄÂÄÄÄÙ ÂÄ back Garden
³ DC³ ___ ALC _____ ³13.8V _³_ ³ RF
³ À´PSU³ ³SMPSUÃÙ //// ³Sniff
³ DC<Ä´25AÃÄ<M ³ 75A ÃÄ<M ³
³Y1 ÀÄÄÄÙ ÀÄÄÄÄÄÙ ³
_³___ Y2 ³ ÚÄÄÄÄÄÄ¿
³SCOPEÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ M<Ä´FilterÃ<Mains
³_____ÃÄ<M ÀÄÄÄÄÄÄÙ
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 and off air record and 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 and 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, and keep the ALC drive level correct.
The PA helps a lot, and when I go back to QRP stations M6s etc, and 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" and "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, and the older 1977 Commercial PA with high levels of
NFB, and 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. and 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.
I use 3 noise systems:- 1/ JPS ANC-4 Noise Canceller (null steerer), 2/ rig's
tuneable Noise Blanker, and 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, and 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 from over drive of the PA!
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"
"Using 2 HF PAs".
Why Don't U send an interesting bul?
73 de John G8MNY @ GB7CIP
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