[amsat-bb] Possible source of QRM on AO-51
andythomasmail at yahoo.co.uk
Thu Nov 8 02:49:29 PST 2007
Those of us in N Europe suffer from qrm on AO51,
southbound from the poles, from fm transmitters
thought to be in N Russia.
I have just come back from China, where thanks to
Michael and others, I met the Shandong ARS in Jinan.
Amongst other hospitalities, the group took me to a
street selling handhelds as well as other stuff like
mobile phones, mobiles and I think repeaters.
There I bought a VHF handheld for 180 RMB, about £12
UK or $26. (Including battery, charger, belt clip and
antenna!) This promises 2.5 W out into keyboard entry
and/or stored channels, either simplex or separate
tx/rx. The model has the PU HUANG brand name, model
PG5118 and covers 140 to 170 MHz, no tone or ctcss.
The keyboard entry will only accept 5khz steps.
The company name is Guang Yuan Electronic Co Ltd; I
can't read the address -it's in Chinese - but was told
it was made 100km from Xiamen in Fujian province.
The instructions offer bands as follows:
200-270,400-420,430-450,450-470, 400-470 MHz.
Other handhelds on sale in Jinan covered 70cms and the
145-175 and 450-470 MHz bands - these were more
In Beijing at the Silk market (4th floor) there were a
few stalls selling "Walky talkies" with the same
frequencies, and they recommended a "Chinese Kenwood"
that looked like my Pu Huang but had Kenwood written
on it instead. They had other "Kenwoods" and
"Motorolas" but your guess is as good as mine.
Another name is Bei Feng (BF) and their address is:
Fujian Quanzhou BeiFeng Telecom Sytsems Ltd
email: beidian at pub2.qz.fj.cn
Also in Beijing I got hold of some flyers for the
HONGO range produced by the Fujian Quanzhou Hongda
Electron Industry Ltd.
HD-45AT : 136-174, 400-430 0r 440-470, 4/5w, ctcss,
12.5 khz channels.
A-88: : same bands, 2.5w, no ctcss, 12.5 khz channels.
HD-8800:400-470,no ctcss, QT/DQT (don't know what that
is),5w, 12.5 khz steps.
What's all this got to do with AO-51, well the box my
Pu Guang came in is written in Chinese, English -and
Russian. The Russian reads "Seriiniaya osobennaya
vnutrisvyazhaya sistema" (I'm transliterating from the
cyrillic) which reads something like "serial personal
home system" - I'll get a better transaltion from my
Russian tutor tonight.
So I conclude that these sets are being sold on the
Russian domestic market - why else write in Russian on
the box? And they are therefore a strong candidate for
the FM uplink qrm on AO-51 when the ctcss access is
Finally, looking at all the above specs., while some
of them do have ctcss, and they could have 5 or 12.5
or 25 kHz steps, none have the odd 6.25 kHz steps.
Maybe future FM sat builders could get around
unintentional qrm this way?
If anyone wants a scan of the "manual" or flyers
please email me off the list.
73 de andy G0SFJ
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