On the 1st of September 2002 successful two way contacts were made on 75976.2¹ MHz between G3PYB/P located near Ventnor, Isle of Wight and G8BKE/P and G8ACE/P located near Highclere to the west of the A34 and south west of Newbury, Berks. The distance 79.6km. Contact between G3PYB and G8ACE was on NBFM² and between G3PYB and G8BKE on NBFM² and CW (G8BKE)³. The success in making this contact, thought to be a new UK distance record for this amateur band was we think due to favourable humidity conditions prevailing on the day. Attempts during 2001 were by and large prevented by the Foot & Mouth restrictions. During earlier 2002 attempts the weather conditions were either unfavourable due to rain or excessive humidity often above 80-90%. G3PYB measured the humidity as low as 39% during these tests. The BBC web weather information gave humidity values of 58% for Ventnor and Newport IOW, 43% for Southampton and 35% for Andover and Newbury for 1400 GMT.  All significantly lower values than we had experienced before. The attenuation at these frequencies is significantly affected by water vapour. 
    Earlier experiences show that in choosing a suitable test path a K value of 1 is much more likely to lead to successful exchange of signals rather than K=1.33 Additionally at least 20 metres of clearance has been found necessary between any intervening high ground and the LOS path to avoid penetration of the fresnel zone by trees and buildings when examining possible path profiles. These constraints mean that few long paths from accessible sites in the South of England will meet the concluded criteria for successful communication at the limited transmit power levels we can obtain.

Listen to G8ACE relayed back on 2m FM for recording.

Listen to G3PYB  These are compressed recordings for faster download with some loss of quality.

Notes:

1.UK preferred frequency for narrow band operation.  75976 - 75978 MHz.
2.G3PYB and G8ACE use Impatt diode transmitters producing a mW or two of 
  power.
3.G8BKE uses a beam lead diode multiplier transmitter producing a little 
  less power than the Impatt devices.
4.Receivers are based on the DB6NT design using anti-parallel beam lead 
  mixer diodes.
 

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From: w5lua [al_ward@agilent.com]

On September 7, 2002 at 1235UTC, WW2R/5 and W5LUA made a record breaking contact on 24192 MHz. Dave was operating portable in EM41HC near Natchez, Miss and W5LUA was operating from his home in EM13QC, Allen, Texas. CW signals of 549 were exchanged. 

DX based on 6 digit to 6 digit grid square is 337.3 miles or 542.8 km

The equipment at WW2R/5 consisted of a 2 ft dish fed through 2' of flexible waveguide by a retuned Hughes 12-18GHz TWT running 11W output. The 1.8dB HEMT preamplifier was mounted directly on the waveguide switch. The homemade transverter fed an IC402 at 435MHz. Frequency calibration was achieved by a frequency counter locked to GPS by an HP Z3801A time/frequency standard. Signals on 10GHz were consistently around 10dB above the noise. After the QSY to 24GHz, and overcoming the surprise of hearing anything, initial signals were estimated at around 6dB above the noise but by the end of the QSO were barely audible above the noise.

The equipment at W5LUA consisted of a 2ft MACOM dish with azimuth and elevation control at 65ft. LNA noise figure at the dish measured 3 dB. I was using an Alelco TWT producing 50 watts in the shack. The actual power getting to the dish was considerably less. I had two 1.5 dB loss WR-42 flexible pieces of waveguide in the shack feeding about 60 ft of EW-180 waveguide with about 4 dB loss and another 1.5 dB loss WR-42 flexible jumper at the antenna. The transmit losses add up to 8.5 dB giving me about 7 watts at the feed. My azimuth rotator is an Orion 2800 which allows me to get to within tenths of a degree. I use a small actuator to give me about -1 to +16 degrees elevation control. This worked OK for horizon shots for AO-40. We first tried 10 GHz where signals were 5 to 10 dB over the noise. We made an easy contact and then QSYed to 24 GHz where I was much surprised to hear Dave about 10 to 15 dB over the noise on a nice peak. The initial peak may have been due to airplane
  scatter but afterwards the signals became more constant, they settled in about 10 dB over the noise for several minutes and an easy QSO resulted.

Based on 6 digit grid square to 6 digit grid square EM13QC to EM41HC DX = 337.3 miles or 542.8km.

Based on actual latitude/longtitude locations, the DX calculates to be  338.2 miles or 544.3 km establishing a new world record on 24192 MHz.

W5LUA 33 deg 6 min 53 sec north by 96 deg 36 min 54 sec west WW2R/5 (from map) 31 deg 7 min 22 sec north by 91 deg 20 min 33 sec west

Weather at EM41HC was 75 degrees F and 88% relative humidity with relatively clear skies with some high clouds. Weather at EM13QC was 72 degrees F and 70% relative humidity with skies partly cloudy. 

Attempts to repeat the contact over the same path 12 hours after the initial QSO resulted in no signals being identifiable either way on 10GHz, suggesting the morning QSO was under enhanced tropo conditions. No signals were heard on 2 meters or 70 cm at the time of the contact. The sked was setup earlier in the week via email with no liaison on any band including cellular! Numerous attempts over a slightly shorter TX-MS path on 10GHz in July also resulted in no signals being identified. 

Submitted by W5LUA and WW2R on September 9, 2002

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On the 20th June 2002, DB6NI and DL6NCI (JO50VI) worked IW4CJM/P 
in JN72MA, a distance of 961kms. There is some belief that the QSO was 
a mixture of sea ducting and rain scatter, although QSOs of over 700kms 
were being worked over land at the same time.

DB6NI is DL6NCI's daughter and had been licensed for three days at this 
point. What an introduction to amateur radio!

Information supplied by: Jonathan  HB9DRD/G4KLX

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Al Ward, W5LUA, made a two way CW EME contact on the 9cm band 
with OK1CA in Czechoslovakia on the 13 June 2002. The distance
between Al in EM13QC and OK1CA in JO70GM, is 8553 km.
 

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The UK lost one of its most active 10GHz enthusiasts recently when G3KEU passed away on Tuesday, 14 May 2002. 

Tim Leighfield, G3KEU died of cancer in a hospice near his home in Swindon. He had entered the hospice just a few days before his death at the age of 71 years. He is survived by his wife Ena and his sons and daughters. His funeral took place at Swindon on the 22nd May and several microwavers were in attendance.

Many of you already knew that Tim had been very ill with cancer over the past few months. He struggled on bravely but the last few weeks unfortunately saw a rapid deterioration.

Tim is yet another of my close microwave friends to go this way in recent years and, like the others, I shall miss him greatly. He was always there, out on the hills with Roy, G3FYX,during the cumulative contests, on from home during the week running his daily morning 10GHz sked with G3LRP just a few miles north of me and then on the 80m microwave net soon after. There is no doubt that much of the 10GHz activity in the southern part of the UK hinged around G3KEU for he was perhaps the most active UK operator on that band.

Plans are afoot to set up a lasting memorial to Tim, possibly in the form of a beacon (GB3KEU ??) and/or a contest trophy. The webmaster would very much appreciate hearing from people who may have constructive ideas and comments on this.

Many emails have been received at this website from radio amateurs all over the UK and from Europe expressing their sadness at the news. It is hoped to send a collated copy of these to Tim's family. If you wish to comment please email the webmaster.

You can read more about Tim, and his microwave activities, by going to the photo album section at the following link:

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Two emails,  recently received,  describe this exciting advance in amateur microwaves. Who would have thought,  five or ten years ago,  that 24GHz EME would be a real possibility? Well, it's here! 

Congratulations to all involved in these historic contacts. Read on ....

EMAIL 1:
From: "Barry Malowanchuk" <ve4ma@shaw.ca>
Sent: 22 April 2002 
Subject: Lots of 24GHz EME this weekend !

On April 18 and 20 Sergei, RW3BP, had his first QSOs on 24GHz with Al W5LUA (M/M) and Barry VE4MA (O/M). On Sunday April 21 Sergei worked AA6IW Lars for initial #3, and a first 24 GHz EME QSO for Lars. What is more remarkable is that the moon was only at about 7.5 degree elevation for Sergei at the end of this QSO. The atmosphere normally absorbs RF at low angles on 24 and adds Rx noise from the temperature of the atmosphere. This is certainly a new 24 GHz distance record (KO85ws to CN87vi). Lars observed a very much narrower spreading of RW3BP than VE4MA.

Also today VE4MA worked VE7CLD(M/M) for a new initial #3 and a new country #3 (a first 24 GHz EME QSO for Gunter ), and then AA6IW (M/M) for initial #4. The Libration "smearing" was bad for these QSOs as the moon was at a local hour angle of -25 degrees.

Unfortunately Al, W5LUA, missed all the activity as he was in New Orleans!
Next month is sure to bring much activity and many new QSOs.

All stations are running high power TWTs (>75 Watts), mostly courtesy of Paul Drexler W2PED.

73 Barry VE4MA

EMAIL 2:
Subject:  24GHz EME
Date: Sun, 21 Apr 2002
From: "Sergei RW3BP" <rw3bp@co.ru>

On 18 and 20 April I had my first QSOs on 24 GHz with Al, W5LUA, and Barry, VE4MA.

My station:
ANT - 2.4m (8 feet) offset dish with rectangular horn as a feed (see photo right). I can set speed of Az and El motion to provide autotracking with better then  0.1 degree accuracy in 30min period.

TX - 50W TWT placed at the feed point on water cooled aluminium plate.PS (13kV/5.6kV) is homemade and placed at home.

Rx - DB6NT LNA with 1.65dB NF. Converter and LO by RA3ACE.

I use separate feeds for TX And RX. TX/RX change-over provided by moving TWT - LNA block up and down for 40mm. It takes 0.25 s to move it down to RX position. So it is possible to get own echo very well.In TX position RX feed is shielded by lossy rubber. It is also good reference for noise measurements.

73 Sergei RW3BP

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On Friday, March 1,2002, we completed several QSOs that we believe set a new North American and new world record on 75GHz.

At 12:30pm PST W0EOM completed a QSO from Mt.St.Helena, California (CM88QQ) to KF6KVG on Mt. Umunhum (CM97AE) on 47.040GHz.  Signal levels were 20+dB out of the noise. Several minutes later, W0EOM and AD6FP both completed QSOs from Mt.St.Helena to KF6KVG on Mt. Umunhum on 75.600 GHz. Once again signal levels were 20+dB out of the noise. The distance from CM88QQ to CM97AE is calculated as 175.3km.

After several false starts in arranging a record attempt, Will, W0EOM, finally got everyone to agree to go out on Friday, March 1. Will and Gary AD6FP went to Mt.St.Helena, Bob KF6KVG went to Mt. Umunhum and Lars AA6IW was in Los Altos Hills. Previous tests indicated we might have difficulty with paths longer than 160km on 75GHz so Lars was positioned 156km from the Mt.St.Helena end.

Arriving at Mt. St. Helena Will and Gary found the traditional operating spot in disarray. High winds the previous evening had caused a tower to fall partially destroying the wooden deck that is usually used by the local microwave crowd.  The winds were also still pretty high, estimated at 35 to 40mph.  After some exploration we were able to find a sheltered spot out of the wind and set up the radios.

A quick try of the 10GHz radio resulted in nothing heard from the local beacon or Lars’ high power transmitter so we concluded the transverter had failed.  We were hoping to use the 10GHz signals to determine bearings to Mt.Umunum so when the radio failed things were looking dismal.  Luckily Will was able to find the signal from Bob on 47GHz with a bit of panning of the dish.  Once peaked up on 47GHz we had a good optical target to use to sight the 75GHz dishes.

The 47GHz signal levels were sufficient to allow Bob to complete the exchange using NBFM rather than CW. After aligning the 75GHz dishes on the same heading as the 47GHz dish, the 75GHz signal from Bob was quickly located on the Mt.St.Helena end. To our surprise, the 75GHz signal level was as good as the 47GHz level!  The two 75GHz contacts were quickly completed from both W0EOM and AD6FP to KF6KVG. The 75GHz signal from Mt. Umunhum peaked 23dB out of the noise with 6-8dB fades.

After working Bob on 75GHz, Will and Gary repositioned their dishes and worked Lars, AA6IW, on 75GHz at 156 Km distance (this would have previously been a 1km increase in the 75GHz world record). Signal levels from Lars on the 156km path were comparable but slightly less than the levels from Bob on a 176km path.

The equipment used at each station is as follows:

W0EOM:  47GHz:  60mw xmit power, 2' cassegrain dish, 4dB NF rcv.
        76GHz: 8mw xmit power, 18" cassegrain dish, 15dB NF rcv.

KF6KVG: 47GHz:  >20dbm xmit power, 2' prime focus dish, 4dB NF rcv.
        76GHz: 10mw xmit power, 1' prime focus dish, 15dB NF rcv.

AD6FP:  76GHz:  4mw xmit power, 3' cassegrain dish, 15dB NF rcv.

AA6IW:  76GHz: 4mw xmit power, 18" cassegrain dish, 15dB NF rcv.

All the radios use LOs that are locked to either precision OCXOs or Rubidiums.

Weather conditions were very favorable for mm-wave propagation:

18% to 26% rel. humidity along the path. 40 to 65 degree F temperatures

On the way down Mt. St. Helena we could easily see the snow capped peaks of the Sierras over 150 miles away.  The unusually low humdity as well as the clear atmospheric conditions were major factors in making QSOs on this record path.

Best regards to all from:

Will  W0EOM
Bob  KF6KVG
Gary  AD6FP
 
 

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From: Brian Justin [wa1zms@worldnet.att.net]
Sent: 24 February 2002 03:13
To: Microwave Reflector; G3PHO Peter Day;
Subject: New DX...

Hi all-

I'd like to report what looks to be a new World, as well as North American DX record for the 241GHz band.

Earlier today, myself (WA1ZMS/4) and Pete, W4WWQ set several new DX records for the band. We first worked over a distance of 3.8km, then 6.1km, and finally 7.3km at which point we ran out of signal margin for the WX conditions at the time. (Former World record was 2km by DB6NT and NA record was 1km by W2SZ/4)

The details of the claimed 7.3km record are as follows:

Feb 23, 2002  19:45z
WA1ZMS/4 located at 37-22-56N 79-14-43W (FM07ji)
W4WWQ/4  located at 37-21-13N 79-10-15W (FM07ji)
a location to location distance of 7.3km

WX at time of QSO was:
Temperature  8.3 degs C
Dew Point  -2.8 degs C
Relative Humidity  46%
Pressure  1017 millibars
Calculated loss of 1.70 dB/km

Photos and an audio file are now be posted on www.mgef.org

The stations used are improved versions of the ones used in Dec of 2001 for the former North American DX record. The improvements involved the phase locking of the 80.6GHz Gunn sources back to homebrew ovenized crystal oscillators. This allowed the use of FSK keyed CW and the use of a narrow band receiver IF.  The IF receivers were an Icom R-7000 and a Yeasu FT-817. The IF freq was 439.7MHz +/- some frequency drift. The ovenized crystal oscillator frequency is effectively multiplied some 2220 times to get to 241GHz! The stations were able to maintain better than 2 KHz stability over several minutes. Frequency drift was still a problem however and with weak signals several repeats of the exchanges were needed to complete the 6.1 and 7.3km QSOs.  If dryer WX comes along, better DX may be achieved.

I'd like to thank Pete, W4WWQ for his roving efforts and to WA4RTS for the loan of an R-7000 in place of him being able to assist with this weekend's QSOs, and to Jeffrey Hesler of VDI.

73,
Brian, WA1ZMS/4

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