These are 3.4GHz consumer units which are available on eBay for about £6 each.
They come in a sealed unit and consist of a transceiver board and patch antenna.
Out of the box they receive on around 3.45GHz and transmit on 3.35 Ghz.
The units are full duplex. For Amateur use it will probably be necessary to remove
the input and output diplexers replace the input with a cable for transmit and one
for receive. On the output insert a coax relay. The units are quite broadband
otherwise and should make a quite good transverter for 3.45 Ghz provided you use
an IF of around 900 MHz. The output is about 300 mW and the PA module can
be linearly biased. I am also expecting delivery of an ex-Ionica 15 watt PA.
Initially I will try both of them out on DATV but eventually I may use them on
SSB using the USRP2 SDR as the IF.
For a change I put back up the 4M vertical dipole I use on FM. After I found
a duff connector in the feed line and did some adjustment to the antenna I
got the following plot, 70 MHz is in the centre. Yes when I connect the antenna
up to a real radio I get the same results as the 4170 measured. This is a great
piece of kit and the latest version of the software includes a TDR function. Which
correctly showed the position of the problem in my feedline. I have had this unit
for a number of years but as I don't do much antenna work this was the first time
I have used it in anger. I think I may be making some more antennas after this
pleasant experience.
The reason for the two overlaid plots is that they show the dipole with about
1cm change in length.
I have been adding the ability to parse the transport stream
from the dongle to my code. Once it has found the PAT it
finds the PMT and from that the Video and Audio PIDs.
It requires this information to tell the demux which transport
stream elements it needs to extract.
Currently I am waiting for some SMA and N crimp
connectors from China. Then I will be able to install
proper leads between the various modules rather than
the trees of adapters I am using at the moment.
The Chinese connectors have arrived (very quickly)
Unfortunately with the N connectors the centre pin
is slightly larger than the PTFE hole. With the SMAs the
centre pin hole is smaller than the RG58 cable inner. Both
problems can be fixed but considering I am using MIL-SPEC
RG58U from a proper source and that the connectors were sold
as RG58 cable ones I am a bit disappointed, but hey they were
cheap!
