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M0BTZ England flag England

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Maidenhead Locator = IO90GX (Oct 2006 ->  Present).

((Previous locations = IO91LC (May '98 - Sept '03), IO81KQ (Sept '03 - Aug '05), IO81PB (Sept '05 - Sept '06))

WAB Square = SU32

WAB Book Number = 15073.

National Grid Ref = SU 38006 20020

Latitude = 50 deg 58' 42" North

Longitude = 1 deg 27' 36" West

Site = ~40m ASL


To work out your QTF / Beam heading to my station. Try this link :



Hi all,

I am a 32 year old RF engineer currently located in Romsey, Hampshire.

I hold the following callsigns :-

  • M0BTZ (Current callsign, since May 1998).
  • 2E0ARB (since Dec 1997. Still used sometimes to work DX on VHF/UHF with QRP!).
  • 2E1FMD (since Sept 1996. Mainly active 70cm FM),

I started the hobby as an SWL from ~1991 whilst still at school, and it has stuck with me ever since!

I am a bit of a homebrew fanatic. A big part of the hobby for me is building my own radio equipment for my shack. The radio shack contains a mixture of homebrew and commercial equipment.

The photos show my shack, and some of the homebrew power amplifiers for VHF / UHF. On the opposite side of the room (not shown) is my construction and test bench. This allows me to listen for activity on 2m/70cm whilst homebrewing a project!.


I enjoy operating on all bands, with a bias towards Low-band DXing in the winter and VHF/UHF DX during the summer.

I tend to operate mainly on the VHF/UHF bands in SSB/CW modes. Currently QRV on 50MHz, 70MHz, 144MHz, 432MHz and 1296 MHz (recently added). I particularly enjoy contesting and DXing. 

I also appear on the 160, 80 and 40m bands during the Winter months, and tend to be most active on 40m.

I prefer to use the older Icom VHF/UHF transceivers (IC251E/451E/551/275A) which work well for me and I like the ergonomics. Seperate single band rigs for each VHF/UHF band are my preference.

For HF, I prefer using the older Kenwood equipment for the HF bands (TS830S & TS940SAT).  

I use transverters for operation on the 4m, 23cm and 13cm bands and drive them with old Icom  IC-251E 2m rig.

In the past between 2001 -> 2006, I have activated the University of Surrey club station, G8AHK during VHF/UHF UKAC contests.


Nov 2011 - Present:- Romsey, Hants (IO90GX). 

Shack setup

SWL Setup :-

  • Lowe HF-150 / Lowe HF-225 Receivers.
  • Racal RA6790GM Receiver.
  • Homebrew "K5IRK Progressive Rx" Single conversion superhet ,9MHz IF. - Someday, I will put together a matching TX!)
  • Eddystone 840C (1963 vintage)
  • Homemade Medium Wave and Longwave Loop Antenna.

HF Setup :-

1st Station :-

  • TS-940SAT + SP-940 + MC-50 Homebrew HF PA (160 - 10m incl. WARC bands). 
  • Pair of RCA 813's Tubes in grounded grid arrangement, with 2.7kV on the anodes. ~400W o/p. Usually used on 160m, 80m & 40m. Built in 2002 as a student, and improved over the years. Drive power is fed via a tuneable L-matching network to the tube heaters. All removeable covers have interlocks to isolate the EHT supply, and there is a seperate bleeder resistor chain to discharge the HT (monitored with Voltmeter near ground potential). The PSU uses a bridge rectifier (5 x 1N5408's per side) with a 40uF 5kV large russian oil filled paper capacitor and has soft-start facilities. Cooling air is drawn through the PSU compartment, a second fan is used to cool the tubes. A third fan on the lid sucks out the warm air exhaust through screening mesh through the top cover. Cooling is excellent, and the amplifier just loafs along at 400W for hours without even getting warm. RF output is fed through a Kenwood LF-30A Low Pass Filter. Good reports have been received on 80m SSB from locals, and has survived a number of lengthy CW contests (CQ WW 160m) so far to date. It is old technology, but it works very well and I have a box full of spare tubes!

  • Homebrew 1kW ATU - W1FB "SPC Transmatch" design with two bigC's and Rollercoaster L + T200-2 toroidal 4:1 balun.

2nd Station :-

  • TS-830S+AT-230 ATU+SP-230+SM-220+VF-240+MC-50 / Shure 444 Mic.

Other Gear :-

  • Icom IC-751A + Shure 444 @ 100W.
  • Also various homebrew HF QRP transceivers for fun.

Current HF antennas:

  • For 10m :  2 ele Cubical Quad Beam (Homebrew) @ 5m mean height, fixed to Central America (W-S-W). Fed with quarterwave 75 ohm coax line transformer for a good 1:1 match.
  • For 10m, 15m, 20m : 3 - Band Vertical (1/4 lambda) mounted with the base at 15ft agl. 8 x Sets of elevated radials (1 set = 1/4 wave for each band). Most of the radials run over the top of a garage roof. The others are suspended at the same height above ground. 
  • For 10m -> 80m : Homebrew Inverted-V Doublet. W3DZZ design but fed with 450 ohm ribbon @ 40ft. Works best on 80m / 40m as a high angle radiator, but still a useful antenna on the higher bands too.
  • For 160m & 80m : Homebrew 50ft Vertical wire (supported by Fibreglass mast). Impedance matching is provided at base for 160m & 80m. This is my favoured antenna for DX working on the low bands. Ground system consists of ~50 short radials plus multiple earth stakes. For 80m operation a small amount of inductance is added to tune the vertical to either the SSB or CW end. For 160m operation, I use a large 4:1 balun in reverse to step down from 50ohm to 12.5ohm, and then tap onto a large air-spaced loading coil (10" diam) made with 6mm copper brake pipe. With this combination I get an good match, and I can change coil taps easily. The 2:1 SWR bandwidth is about 130kHz on 160m. 

Both the In-V and the 50ft Vertical share the same fibreglass mast to save space. I can switch between all antennas from the shack. As I usually operate on 80m, the Inv-V usually outperforms the vertical for high-angle signals (UK & Europe). The vertical is usually better for low-angle DX working into other continents. I also have matching at the base of the vertical to allow me to use it on the 160m band when required.

  • SWL:- Half-size G5RV in loft space.

50 MHz Setup

  • Icom IC-551
  • 4CX350A Amplifier (Homebrew) or TE Systems 50MHz 150W SSPA 
  • (Homebrew 2 x 4CX250B PA (in 19" rack) - Not yet operational)
  • Homebrew BF981 Preamp.
  • 3ele Homebrew DK7ZB short boom yagi.
  • Other antenna options : Switched attic space wire beams. 3ele wire beam (North), 2ele wire beam (East). 5ele F9FT.

(Operate SSB/CW)

70 MHz Setup :-

  • IC-251E+muTek Prime mover with elderly Spectrum 4m transverter TRX4-2I
  • Homebrew 10W PA with an MRF238 device.
  • Homebrew Masthead BF981 Preamp.
  • Homebrew 2 x 4CX250B PA (currently off air) or Homebrew desktop 150W SSPA with MRF-150 (under construction).
  • Antenna = Homebrew 5ele DK7ZB 70MHz Yagi.

(Operate mostly SSB/CW)

144 MHz Setup :-

  • IC-275A / IC-251E+muTek.
  • Homebrew 4CX350A PA.
  • Mirage 160W SSPA. Run at 100W most of the time. (Backup)
  • Homebrew W1SL (2 x 4CX350A PA) (in a19" rack).
  • Landwehr GaAsFET Preamp or Homebrew BF981 / MGF1302 Preamps.
  • Antenna = 11 ele F9FT Yagi.

QRV mostly SSB/CW.

FM Setup : FT7900 + 50W and X-300 Colinear Antenna (2*5/8ths lambda) at 7m AGL.

432 MHz Setup :-

  • IC-451E - Modified front end with BF998 for slightly more gain & lower noise figure.
  • 100W SSPA
  • Homebrew K2RIW 2 x 4CX250B PA (19" rack) - RF Deck construction in progress.
  • Homebrew Compact 3 x 2C39 70cm PA (DJ9HO design)
  • Homebrew MGF-1302 LNA or SSB Electronics masthead preamp.
  • Current antenna = 24 ele Homebrew DJ9BV design at 11m AGL.
  • Other options : Pair stacked F9FT 21-ele yagis, (old!), Pair homebrew 19 ele DL6WU yagis.

FM Setup : FT7900 + 45W and X-300 Colinear Antenna (5*5/8ths lambda) at 7m AGL.

1296 MHz Setup :-

  • IC-251E+muTek.
  • DB6NT transverter (built from kit) + Homebrew Mitsubishi M57762 module PA for 15W o/p.
  • SHF Electronik GaAsFET masthead preamp / Homebrew MGF-1302 Preamp.
  • Homebrew 4 pole Interdigital BPF.
  • Homebrew 2 x 2C39A Cavity PA & 1.2kV Homebrew PSU (~150w) - Nearly finished build now!
  • Current antenna = 42 ele homebrew Quad Loop yagi.
  • Other options, 26ele DL6WU, homebrew 2 x 37 ele Loop Yagi (~4m boom), Homebrew Stacked Double Quad (DJ9HO style) for /P, Homebrew 3m Dish under construction (to use on EME - one day!), 48ele DL6WU Yagi Homebrew.

Slowly building a single 55ele DL6WU yagi, all elements filed to length, within 0.01mm... 

I plan to make a box of 4 yagis + H-frame. It is a little easier to handle than a big dish but more complex to build!

2320 MHz Setup (Not QRV yet)

  • IC-251E+muTek.
  • DB6NT transverter. (Recently de-bugged and now working, needs casing and finishing off).
  • Homebrew 4 pole Interdigital BPF.
  • Homebrew 60W SSPA (DC0DA module) + 28V PSU
  • Single 2C39 cavity PA (alternative).
  • Homebrew MGF-1302 Preamp.
  • Homebrew 4 x44 ele G3JVL Loop Yagis on 2m boom and H-frame / 4 x Homebrew Stacked DJ9HO Double Quad with combiner for /P / Building DL6WU yagis.
  • Homemade 3m dish under construction (EME)

(SSB/CW - Plan to be active as a small EME station one day)

Not currently QRV :- Need to box up the transverter with Sequencer, Relay and 60W PA.

3410 MHz Setup (Not QRV yet)

  • Homebrewed 70-ele loop-yagi / 1.2m solid Dish.

Collecting bits for a transverter.

Recently received some GaN 40W Power Transistors to have a go at homebrewing a solid state PA for 9cm's!

10 GHz Setup (Not QRV yet)

  • Homebrew WBFM Gun diode transceiver under construction.
  • 60cm solid dish (for /P)
  • 1.2m solid dish (awaiting a feed horn!)
  • Pair homebrew 20dBi Horns for WBFM transceivers. 
  • No transverter yet - I will be looking to become active on 10GHz SSB/CW, once the other bands are sorted out.

Groups & Memberships

  • RSGB Member.
  • ARMMS Microwave Society.
  • UK Microwave Group.
  • UK Six Meter Group (UKSMG), #2929
  • Blacksheep Contest Group (M0BAA) - VHF/UHF Contesting
  • Travelling Wave Contest Group
  • Itchen Valley ARC
  • Wey Valley ARC (Visiting member only)
  • ex - University of Surrey EARS 
  • Member of the IET (Institution of Engineering and Technology), and working towards CEng.
  • Alumni of University of Surrey, Guildford, Surrey, UK. (Electronic Engineering)
  • Former employee at Roke Manor Research Ltd.

Interests within Amateur Radio

  • VHF/UHF DX (Summer)
  • Microwave bands
  • VHF/UHF Technical aspects
  • Low band DXing (Winter)
  • Home Construction.
  • Contesting
  • Antennas.

Test & Construction bench

The test bench sits directly opposite the operating position. Test gear includes Soldering irons, Oscilloscope, Sig gens, VHF/UHF signal sources, Freq Counter, Homebrew RF dB meter, LC meter, AF Sig gen, Two-tone signal source etc etc...Usually this bench is in a mess!!.

Operating Habits

  • I am a "Search and pounce" type of operator- A habit from my SWLing days!
  • Operate in VHF /UHF contests.
  • Casual HF Low Band DXer during Winter.
  • VHF/UHF DXer during Summer.
  • I operate mainly on SSB, but also some CW.
  • My CW operating is in development, but I can comfortably operate at 12 - 15 wpm when concentrating. If you do hear me on CW, then please have a little patience. My CW operating is not perfect, but I am gradually improving with practice.

QSL Details

You may QSL either via eQSL or direct to my home address with an SAE, or you may QSL via the RSGB Buro or eQSL.

My QSL manager is 2E0VAG.

I am collect cards for HF DXCC and VHF/UHF awards.

I collect Locator Squares / WAB Squares / French Departments / German DOK information and US States.

I particularly value cards from any stations worked on VHF/UHF via long distance Tropo/Sporadic E/MS/Aurora/EME propagation modes, so please do QSL!

Other Interests

My other general interests also include Astronomy, Road Biking, Rowing, Music and HiFi/Audio.

1945780 Last modified: 2015-05-07 16:32:01, 14700 bytes

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