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Re: [TenTec] OT: Holiday SDR Project

To: Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de>
Subject: Re: [TenTec] OT: Holiday SDR Project
From: Carl Moreschi <n4py3@earthlink.net>
Reply-to: n4py3@earthlink.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 08 Nov 2014 22:45:52 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Yes, I agree the RF sense is not a good way. That's why I added the line about using the amp key line.


Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com

On 11/8/2014 10:42 PM, Rick - DJ0IP / NJ0IP wrote:
That is a very good tip, Carl.
Reminds me of the old Johnson T/R switch I used 50 years ago (hi).

My only comment is, one should absolutely NOT use the RF sense for switching
when working in CW.
That could end up being too slow and blow the 2nd RX.

It is fine for SSB using PTT.
Not sure how it would be using SSB and VOX.
I guess that would depend on how loud you say your first "uuuhhh".

With any of the late model Ten-Tec transceivers (ORION, OM7, Eagle), the
delay after keying the PTT is plenty long to allow the 1708 to switch.

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)

-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Carl
Moreschi
Sent: Sunday, November 09, 2014 4:26 AM
To: Don Rasmussen; Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] OT: Holiday SDR Project

What radio are you using?  Many radios have an easy way to share antennas.
If that's not an easy solution then the MFJ1708 can do the job.  See below.

The solution to share antennas is to add an MFJ-1708 T/R switch.  This

unit will automatically sense RF from the transmitter and then remove

the panadapter radio from the receive antenna connection.  But the MFJ

switch will also remove the transceiver from the transmit connection

while in receive.  So the MFJ switch needs a very simple mod.  You

must solder a 14 gauge wire between the transmit and antenna SO-239

connections.  This will then make the switch operate properly for this

use.  Additionally, you can wire the relay to energize from your

radio's amp key line for faster and safer switching.



Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com

On 11/7/2014 5:45 PM, Don Rasmussen via TenTec wrote:


That sounds great Carl, the transceiver and SDR can both be tuned by the
main tuning knob of the transceiver.

Anyone have suggestions on sharing the antenna?

The second receiver needs to have it's input grounded before the
transceiver puts RF on the line.

=======================================================

That will work well for you. My N4PY software can provide everything you
need to keep the softrock and your transceiver on the same frequency.
Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com On 11/5/2014 11:34 AM, Don Rasmussen via TenTec wrote:
After all this talk about the new Flex Series and peripherals it seems
all of my objections have melted away except for the oldest one -
cost! Flex 6300 with FX-PAD and TMate2 are outside of my ham radio
budget but only because I have that amount of money tied up in
existing gear that I enjoy. I did decide to take a look at what Tony
Parks has been up to and found a very inexpensive SDR project for the
holidays. I can enjoy the build and then mess with the software. The
1.8-30Mhz receiver is $68 and the option cabinet is $20.
http://tinyurl.com/qx4ha8p

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