[NLRS] 2304?

[John Toscano]

Jerry:

The 4-connector transfer relay that I got from W0GHZ for my 10 GHz rig
switches the antenna feed between the preamp input and the PA output (of
course), and whichever of those two devices is NOT selected is switched to
a 50 ohm SMA load. If you used two of them to take a common RF transverter
connector to split it to a preamp and PA and thence combine signal paths to
the antenna feed, the PA input and output should not be shorted to one
another, they should both be connected to a 50 ohm load. (2 transfer relays
= 2 independent 50 ohm loads.)  Either you are wrong (something that does
not happen often in my experience) or W5LUA is talking about some funky
transfer relays that don't resemble mine.

73 and season's greetings from balmy South Texas, EL09vu20 de W0JT/5

On Wed, Dec 28, 2016 at 9:27 PM, Dr. Gerald N. Johnson <geraldj at netins.net>
wrote:

>
>
>
>
> On 12/28/2016 8:48 PM, Larry Peterson wrote:
>
>>
>>
>> Excellent to see some interest in 2304 Mhz.  Karl WD9BGA and I each
>> bought transverters from SG-Labs.  See
>> http://www.sg-lab.com/TR2300/tr2300.html  We also have 33cm and 23cm
>> units.  I use this in sport radio during the warm weather when I activte
>> SOTA summits or work hams via pre-scheduled contacts from lookout towers
>> in WI.  I operate 2m, 125cm, 70cm, 33cm, 23cm and 13cm SSB and CW, but
>> given the 50 pounds of equipment I carry up 12 to 35 stories, I choose
>> perhaps three bands I'll operate in a given morning.
>>
>> I was very surprised how well the 13cm unit works.  Karl & I each used a
>> small circuit board antenna that comes with this Bulgarian transverter.
>> We were 8 miles apart and we had S9 or better SSB signals.  I then
>> rotated my tiny antenna broadside, and Karl's sig was still very strong.
>>
>> Karl & I set the North American summit-to-summit record this summer
>> using a 79 milliwatt MESH system and Pidgin chat mode on 2.4 GHz.  That
>> was completely LOS.  We tried twice more and could not repeat the
>> contact, so we are realizing how special that ultra-low power microwave
>> contact was.
>>
>> Now in real operation, I will use my 27-element Directive Systems loop
>> Yagi, with the SG-Labs transverter, with 70cm IF.  Per my Bird wattmeter
>> it puts out 2 Watts.
>>
>> As far as an amp, I could use your help, Jerry.  I like the PE1RKI
>> design.  He has many options.  See
>> http://www.pe1rki.com/40watt13cm.html  I have sufficient LiFePO4 battery
>> capacity to run one.  I wouldn't mind putting out 25 or so Watts.  But
>> my problem is I do not know how to set up the T/R relay switching.
>> Anyone with ideas would be appreciated.
>>
>
> That's where you need a sequencer. If your transverter has two coax
> connectors, on for receive and one for transmit, then you can add the PA to
> the transit side and go to the TR relay. RF relays don't survive well with
> RF present while closing or opening, and PA's don't survive well with full
> RF drive and the relay open for 10 milliseconds or so. Unfortunately
> virtually all IF rigs put out RF before they put out the TX output control
> line. One way to sequence is to run the microphone PTT (VOX not allowed,
> nor KOX) through auxiliary contacts on the TR relay but key the relay with
> the microphone PTT first. Paul Wade has a couple sequencer designs on his
> web pages, and there have been several published over the decades. On 10
> GHz I thought I had some sequencing using the TXinh line of the IF rig with
> some delay on a transistor switching that bias off a modification of the
> DEMI TC, but my 10 GHz TR relay suffered. Now I have the IF (FT-857D) set
> up for PTT only for SSB and CW tx only with the PTT on the microphone
> pushed. So I'm using manual sequencing, manual PTT, then give it audio or
> start keying. Stop the audio or keying before releasing the PTT. Its
> working depending on the SSB transmitter not transmitting a crunch from the
> PTT switch or some kind of transmitter transient which isn't impossible.
> http://www.geraldj.networkiowa.com/papers/CSVHF2010/TxinhtoTC.pdf
>
> DEMI will sell their TC board kit separately from transverters. I have
> bought a couple for future projects.
>
> If the transverter has only one RF connector, you need two TR relays to
> switch the PA in and out or one four connector transfer relay. I've been
> looking at lots of proceedings lately and W5LUA did have an article on
> applying the transfer relay in one of them. Possibly on the technical
> section of the NTMS web site. The only problem with a transfer relay is
> that it connects the PA input and output together when not using the PA so
> the PA has to be disabled to keep it from oscillating destructively.
>
> 73, Jerry, K0CQ
>
>>
>> 73,
>>
>> Larry WA9TT
>>
>>
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