N.E.W.S. MDS and ERP testing on 10 and 24 GHz

16 July 2005

At the annual N.E.W.S. picnic, we did MDS (Minimum Discernable Signal) and ERP testing on 10 GHz and 24 GHz.

To test for MDS, we set up a distant signal source. After everyone has a chance to peak up on the signal, the signal level is reduced one dB at a time - when you can no longer hear it, then you have found the MDS for your system. You decide how well it works, and whether you can hear as well as Don and Dale. As a doublecheck, the frequency is moved a few KHz, then the signal level is increased one dB at a time. If you weren't kidding yourself, you should be able to find it at the same

level as before. Usually, it takes a few more dB to find a signal.

Finally, we also check relative ERP, transmitting one at a time and recording the relative power received at the distant point.

Results very year were pretty good, with 22 participants on 10 GHz and 5 on 24 GHz, plus a couple of higher frequency stations for show. This isn't a competition, just a chance to check out the gear with friends around to help. Most folks had 10 GHz stations that worked pretty well, while a few found problems to fix before the 10 GHz & Up contest in August. Not only do we know our equipment works, but also that there will be some other good stations to work.

Results are shown in the table below. Data was recorded by N1GJ; any mistakes are in my transcription. As a reference point, the W1GHZ station is an 18" Sony DSS dish with a dual-band feed. Power output is 2 to 3 watts on 10 GHz and 1 to 2 watts on 24 GHz. Receiver NF is in the 3 to 5 dB range on both bands.

North East Weak Signal Group

Annual Picnic - 16 July 2005

Test results - 10 and 24 GHz

CALL

10 GHz MDS

10 GHz ERP

24 GHz MDS

24 GHz ERP

N2YYU

-90

dBm

-50

dB

K2CBA

-84

dBm

-6

dB

-80

dBm

W1AUV

-96

dBm

N1LZK

-96

dBm

-2

dB

WW1Z

-90

dBm

-40

dB

N1FOJ

-84

dBm

-32

dB

W1MKY

-96

dBm

-9.5

dB

AF1T

-106

dBm

3

dB

AA1YN

analog -98

dBm

-9

dB

AA1YN

digital -102

dBm

N1SO

-106

dBm

7

dB

N1MJD

-101

dBm

N1JEZ

?

dBm

-6

dB

-99

dBm

5

dB

KA1LEX

-95

dBm

-4

dB

-94

dBm

-12

dB

W1RIL

-107

dBm

REF=0

dB

WA1MBA

-101

dBm

-16

dB

W1FKF

-105

dBm

-6

dB

-95

dBm

REF=0

dB

KA1OJ

-101

dBm

-6

dB

-94

dBm

-4

dB

W1GHZ

-95

dBm

-6

dB

-94

dBm

2

dB

N1EKV

-92

dBm

-12

dB

K2AEP

-98

dBm

-17

dB

KJ1K

-94

dBm

-24

dB

KB2RWW

-93

dBm