30 Aug
2019
30 Aug
'19
9:56 a.m.
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi MD001H
hybrid antenna switch.
Using such a device is easy to delay TX RF entering to the relay box and
preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig itself
during the time there is no connection to the antenna while the Mitsubishi
switch delays it.
It really works great, timing on a pin switch can be done in many ways. For
this experiment I used a RC combination with an ordinary P-channel FET to
switch the bias on the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without
damaging the rig.
After rough tests I would like to know the RF performance of my creation.
And I was in shock.
The data sheet said that the minimum isolation between the TX and RX port is
30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact the
same performance, and another PCB with better separated connections did not
gave better performance.
Using the 9700 as an exciter it will drive my amps with around 7-8 Watt.
Which means that my preamp will have around 70 mW on the output port, and
kill the preamp sooner or later with such a low isolation of the PIN switch.
I do not go on with the MD001H, but would like to know if there will PIN
switches available that are able to transfer up to 20 Watt and have at least
40 dB isolation between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
31 Aug
31 Aug
2:48 a.m.
I measured the TX delay on PA2CHR's IC9700 and it was 34ms, my Dow Key 402A relays
take 20ms to change state and for ground bounce to settle - BUT- why don't people just
have the radio go over last by driving it with an external sequencer? I drive the
sequencer with either a footswitch, a PC , a microphone PTT or a Winkey CW interface.
The final 5th position on the sequencer drives the radio PTT. The 402A relays have
auxiliary contacts and so I use these contacts to interrupt the radio PTT. It is
impossible for the radio to go into TX if the main LNA protection relay is not in the
correct position.
This is absolutely fool-proof and simple.
Using the radio to start a PTT sequence is just asking for trouble in my opinion.
Of course you could use 2 PIN switches for RX/TX separation if your LNA has sufficient
gain to overcome the losses.
73
Conrad PA5Y
From: Moon-net <moon-net-bounces(a)mailman.pe1itr.com> On Behalf Of Peter PA2V via
Moon-net
Sent: 30 August 2019 15:57
To: moon-net(a)mailman.pe1itr.com
Subject: [Moon-Net] IC-9700 switching
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi MD001H hybrid antenna
switch.
Using such a device is easy to delay TX RF entering to the relay box and preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig itself during the time
there is no connection to the antenna while the Mitsubishi switch delays it.
It really works great, timing on a pin switch can be done in many ways. For this
experiment I used a RC combination with an ordinary P-channel FET to switch the bias on
the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without damaging the rig.
After rough tests I would like to know the RF performance of my creation. And I was in
shock.
The data sheet said that the minimum isolation between the TX and RX port is 30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact the same
performance, and another PCB with better separated connections did not gave better
performance.
Using the 9700 as an exciter it will drive my amps with around 7-8 Watt. Which means that
my preamp will have around 70 mW on the output port, and kill the preamp sooner or later
with such a low isolation of the PIN switch.
I do not go on with the MD001H, but would like to know if there will PIN switches
available that are able to transfer up to 20 Watt and have at least 40 dB isolation
between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
7:13 a.m.
Conrad's suggestions seems the most sensible to me.The main relay at the antenna is
50/20ms and its the first thing to switch after getting PTT from mic or pc or
footswitch.25ms later my 2nd relay switches ( input port protection of the preamp), and
preamp switches offAt 50ms the amp keysAt 75ms the PTT from pc keys the rig (software has
an audio delay)At 100ms the PTT from the mic keys the rig.Using the vhfdesign
seqencer.Using split rx line.My 2 cents.JohanOn4iqVerzonden vanaf Samsung-tablet.
-------- Oorspronkelijk bericht --------Van: Conrad PA5Y via Moon-net
<moon-net(a)mailman.pe1itr.com> Datum: 31/08/19 08:48 (GMT+01:00) Aan: Peter PA2V
<peter(a)pa2v.com> Cc: moon-net(a)mailman.pe1itr.com Onderwerp: Re: [Moon-Net] IC-9700
switching
I measured the TX delay on PA2CHR’s IC9700 and it was 34ms, my Dow Key 402A relays take
20ms to change state and for ground bounce to settle – BUT- why don’t people just have the
radio go over last by driving it with an external sequencer?
I drive the sequencer with either a footswitch, a PC , a microphone PTT or a Winkey CW
interface. The final 5th position on the sequencer drives the radio PTT. The 402A relays
have auxiliary contacts and so I use these contacts to interrupt the
radio PTT. It is impossible for the radio to go into TX if the main LNA protection relay
is not in the correct position.
This is absolutely fool-proof and simple.
Using the radio to start a PTT sequence is just asking for trouble in my opinion.
Of course you could use 2 PIN switches for RX/TX separation if your LNA has sufficient
gain to overcome the losses.
73
Conrad PA5Y
From: Moon-net <moon-net-bounces(a)mailman.pe1itr.com>
On Behalf Of Peter PA2V via Moon-net
Sent: 30 August 2019 15:57
To: moon-net(a)mailman.pe1itr.com
Subject: [Moon-Net] IC-9700 switching
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi MD001H hybrid antenna
switch.
Using such a device is easy to delay TX RF entering to the relay box and preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig itself during the time
there is no connection to the antenna while the Mitsubishi switch delays it.
It really works great, timing on a pin switch can be done in many ways. For this
experiment I used a RC combination with an ordinary P-channel FET to switch the bias on
the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without damaging the rig.
After rough tests I would like to know the RF performance of my creation. And I was in
shock.
The data sheet said that the minimum isolation between the TX and RX port is 30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact the same
performance, and another PCB with better separated connections did not gave better
performance.
Using the 9700 as an exciter it will drive my amps with around 7-8 Watt. Which means that
my preamp will have around 70 mW on the output port, and kill the preamp sooner or later
with such a low isolation of the PIN switch.
I do not go on with the MD001H, but would like to know if there will PIN switches
available that are able to transfer up to 20 Watt and have at least 40 dB isolation
between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
1 Sep
1 Sep
9:34 a.m.
Hi All,
I have good results with using negative ( -4 volt DC ) at the ALC connection, pin # 8
Have the -4 volt connected during RX ( No output at all) and use a small relay to switch
this off with the ‘last port ‘ of your sequencer.
I use 3 sma relays (one for each band) to have separate RX/TX possibilities.
The PTT out, pin # 3, is connected to the centre of a 3 way switch for activating one of
the 3 sma relays: on the band you want to TX.
This pin # 3 is also the input for my sequencer: take care: max 200 mA !
73’s, Chris, PA2CHR
Van: Moon-net [mailto:moon-net-bounces@mailman.pe1itr.com] Namens johan.van.de.velde via
Moon-net
Verzonden: zaterdag 31 augustus 2019 13:14
Aan: Conrad PA5Y; Peter PA2V
CC: moon-net(a)mailman.pe1itr.com
Onderwerp: Re: [Moon-Net] IC-9700 switching
Conrad's suggestions seems the most sensible to me.
The main relay at the antenna is 50/20ms and its the first thing to switch after getting
PTT from mic or pc or footswitch.
25ms later my 2nd relay switches ( input port protection of the preamp), and preamp
switches off
At 50ms the amp keys
At 75ms the PTT from pc keys the rig (software has an audio delay)
At 100ms the PTT from the mic keys the rig.
Using the vhfdesign seqencer.
Using split rx line.
My 2 cents.
Johan
On4iq
Verzonden vanaf Samsung-tablet.
-------- Oorspronkelijk bericht --------
Van: Conrad PA5Y via Moon-net <moon-net(a)mailman.pe1itr.com>
Datum: 31/08/19 08:48 (GMT+01:00)
Aan: Peter PA2V <peter(a)pa2v.com>
Cc: moon-net(a)mailman.pe1itr.com
Onderwerp: Re: [Moon-Net] IC-9700 switching
I measured the TX delay on PA2CHR’s IC9700 and it was 34ms, my Dow Key 402A relays take
20ms to change state and for ground bounce to settle – BUT- why don’t people just have the
radio go over last by driving it with an external sequencer? I drive the sequencer with
either a footswitch, a PC , a microphone PTT or a Winkey CW interface. The final 5th
position on the sequencer drives the radio PTT. The 402A relays have auxiliary contacts
and so I use these contacts to interrupt the radio PTT. It is impossible for the radio to
go into TX if the main LNA protection relay is not in the correct position.
This is absolutely fool-proof and simple.
Using the radio to start a PTT sequence is just asking for trouble in my opinion.
Of course you could use 2 PIN switches for RX/TX separation if your LNA has sufficient
gain to overcome the losses.
73
Conrad PA5Y
From: Moon-net <moon-net-bounces(a)mailman.pe1itr.com> On Behalf Of Peter PA2V via
Moon-net
Sent: 30 August 2019 15:57
To: moon-net(a)mailman.pe1itr.com
Subject: [Moon-Net] IC-9700 switching
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi MD001H hybrid antenna
switch.
Using such a device is easy to delay TX RF entering to the relay box and preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig itself during the time
there is no connection to the antenna while the Mitsubishi switch delays it.
It really works great, timing on a pin switch can be done in many ways. For this
experiment I used a RC combination with an ordinary P-channel FET to switch the bias on
the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without damaging the rig.
After rough tests I would like to know the RF performance of my creation. And I was in
shock.
The data sheet said that the minimum isolation between the TX and RX port is 30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact the same
performance, and another PCB with better separated connections did not gave better
performance.
Using the 9700 as an exciter it will drive my amps with around 7-8 Watt. Which means that
my preamp will have around 70 mW on the output port, and kill the preamp sooner or later
with such a low isolation of the PIN switch.
I do not go on with the MD001H, but would like to know if there will PIN switches
available that are able to transfer up to 20 Watt and have at least 40 dB isolation
between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
1:25 p.m.
Hi Chris,
that is exact the same way I use it with my K3 and a sequencer by Hamtech.
http://www.hamtech.hu/sequencer.html#panel2
There is at the last stage a relay supplying a +/- voltage for TXinhibit.
73’s Erwin/DK5EW
Member of the Team of MMMonVHF
<http://www.mmmonvhf.de/> http://www.MMMonVHF.de
Homepage: <https://www.dk5ew.com/> https://www.dk5ew.com
Homepage: <https://www.70mhz.de/> https://www.70MHz.de
Von: Moon-net <moon-net-bounces(a)mailman.pe1itr.com> Im Auftrag von Chris, PA2CHR via
Moon-net
Gesendet: Sonntag, 1. September 2019 15:34
An: 'johan.van.de.velde' <johan.van.de.velde(a)telenet.be>be>;
moon-net(a)mailman.pe1itr.com
Betreff: Re: [Moon-Net] IC-9700 switching
Hi All,
I have good results with using negative ( -4 volt DC ) at the ALC connection, pin # 8
Have the -4 volt connected during RX ( No output at all) and use a small relay to switch
this off with the ‘last port ‘ of your sequencer.
I use 3 sma relays (one for each band) to have separate RX/TX possibilities.
The PTT out, pin # 3, is connected to the centre of a 3 way switch for activating one of
the 3 sma relays: on the band you want to TX.
This pin # 3 is also the input for my sequencer: take care: max 200 mA !
73’s, Chris, PA2CHR
Van: Moon-net [mailto:moon-net-bounces@mailman.pe1itr.com] Namens johan.van.de.velde via
Moon-net
Verzonden: zaterdag 31 augustus 2019 13:14
Aan: Conrad PA5Y; Peter PA2V
CC: moon-net(a)mailman.pe1itr.com <mailto:moon-net@mailman.pe1itr.com>
Onderwerp: Re: [Moon-Net] IC-9700 switching
Conrad's suggestions seems the most sensible to me.
The main relay at the antenna is 50/20ms and its the first thing to switch after getting
PTT from mic or pc or footswitch.
25ms later my 2nd relay switches ( input port protection of the preamp), and preamp
switches off
At 50ms the amp keys
At 75ms the PTT from pc keys the rig (software has an audio delay)
At 100ms the PTT from the mic keys the rig.
Using the vhfdesign seqencer.
Using split rx line.
My 2 cents.
Johan
On4iq
Verzonden vanaf Samsung-tablet.
-------- Oorspronkelijk bericht --------
Van: Conrad PA5Y via Moon-net <moon-net(a)mailman.pe1itr.com
<mailto:moon-net@mailman.pe1itr.com> >
Datum: 31/08/19 08:48 (GMT+01:00)
Aan: Peter PA2V <peter(a)pa2v.com <mailto:peter@pa2v.com> >
Cc: moon-net(a)mailman.pe1itr.com <mailto:moon-net@mailman.pe1itr.com>
Onderwerp: Re: [Moon-Net] IC-9700 switching
I measured the TX delay on PA2CHR’s IC9700 and it was 34ms, my Dow Key 402A relays take
20ms to change state and for ground bounce to settle – BUT- why don’t people just have the
radio go over last by driving it with an external sequencer? I drive the sequencer with
either a footswitch, a PC , a microphone PTT or a Winkey CW interface. The final 5th
position on the sequencer drives the radio PTT. The 402A relays have auxiliary contacts
and so I use these contacts to interrupt the radio PTT. It is impossible for the radio to
go into TX if the main LNA protection relay is not in the correct position.
This is absolutely fool-proof and simple.
Using the radio to start a PTT sequence is just asking for trouble in my opinion.
Of course you could use 2 PIN switches for RX/TX separation if your LNA has sufficient
gain to overcome the losses.
73
Conrad PA5Y
From: Moon-net <moon-net-bounces(a)mailman.pe1itr.com
<mailto:moon-net-bounces@mailman.pe1itr.com> > On Behalf Of Peter PA2V via
Moon-net
Sent: 30 August 2019 15:57
To: moon-net(a)mailman.pe1itr.com <mailto:moon-net@mailman.pe1itr.com>
Subject: [Moon-Net] IC-9700 switching
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi MD001H hybrid antenna
switch.
Using such a device is easy to delay TX RF entering to the relay box and preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig itself during the time
there is no connection to the antenna while the Mitsubishi switch delays it.
It really works great, timing on a pin switch can be done in many ways. For this
experiment I used a RC combination with an ordinary P-channel FET to switch the bias on
the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without damaging the rig.
After rough tests I would like to know the RF performance of my creation. And I was in
shock.
The data sheet said that the minimum isolation between the TX and RX port is 30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact the same
performance, and another PCB with better separated connections did not gave better
performance.
Using the 9700 as an exciter it will drive my amps with around 7-8 Watt. Which means that
my preamp will have around 70 mW on the output port, and kill the preamp sooner or later
with such a low isolation of the PIN switch.
I do not go on with the MD001H, but would like to know if there will PIN switches
available that are able to transfer up to 20 Watt and have at least 40 dB isolation
between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
2 Sep
2 Sep
10:18 p.m.
Hello all....I tried this scheme(putting -4VDC on the ALC) as a method
of "transmit inhibit". What I was trying to do was to not allow any RF
to be produced until I was ready. Unfortunately, it took 2-3sec for the
ICOM Pro2 to recover from the ALC blocking voltage. This was not
acceptable, so I finally dropped the whole thing. Other rigs might
recover more quickly....so your mileage may vary.
73 Marshall K5QE
On 9/1/2019 1:34 PM, Chris, PA2CHR via Moon-net wrote:
Hi All,
I have good results with using negative ( -4 volt DC ) at the ALC
connection, pin # 8
Have the -4 volt connected during RX ( No output at all) and use a
small relay to switch this off with the ‘last port ‘ of your sequencer.
I use 3 sma relays (one for each band) to have separate RX/TX
possibilities.
The PTT out, pin # 3, is connected to the centre of a 3 way switch
for activating one of the 3 sma relays: on the band you want to TX.
This pin # 3 is also the input for my sequencer: take care: max 200 mA !
73’s, Chris, PA2CHR
*Van:*Moon-net [mailto:moon-net-bounces@mailman.pe1itr.com] *Namens
*johan.van.de.velde via Moon-net
*Verzonden:* zaterdag 31 augustus 2019 13:14
*Aan:* Conrad PA5Y; Peter PA2V
*CC:* moon-net(a)mailman.pe1itr.com
*Onderwerp:* Re: [Moon-Net] IC-9700 switching
Conrad's suggestions seems the most sensible to me.
The main relay at the antenna is 50/20ms and its the first thing to
switch after getting PTT from mic or pc or footswitch.
25ms later my 2nd relay switches ( input port protection of the
preamp), and preamp switches off
At 50ms the amp keys
At 75ms the PTT from pc keys the rig (software has an audio delay)
At 100ms the PTT from the mic keys the rig.
Using the vhfdesign seqencer.
Using split rx line.
My 2 cents.
Johan
On4iq
Verzonden vanaf Samsung-tablet.
-------- Oorspronkelijk bericht --------
Van: Conrad PA5Y via Moon-net <moon-net(a)mailman.pe1itr.com>
Datum: 31/08/19 08:48 (GMT+01:00)
Aan: Peter PA2V <peter(a)pa2v.com>
Cc: moon-net(a)mailman.pe1itr.com
Onderwerp: Re: [Moon-Net] IC-9700 switching
I measured the TX delay on PA2CHR’s IC9700 and it was 34ms, my Dow Key
402A relays take 20ms to change state and for ground bounce to settle
– BUT- why don’t people just have the radio go over last by driving it
with an external sequencer? I drive the sequencer with either a
footswitch, a PC , a microphone PTT or a Winkey CW interface. The
final 5^th position on the sequencer drives the radio PTT. The 402A
relays have auxiliary contacts and so I use these contacts to
interrupt the radio PTT. It is impossible for the radio to go into TX
if the main LNA protection relay is not in the correct position.
This is absolutely fool-proof and simple.
Using the radio to start a PTT sequence is just asking for trouble in
my opinion.
Of course you could use 2 PIN switches for RX/TX separation if your
LNA has sufficient gain to overcome the losses.
73
Conrad PA5Y
*From:*Moon-net <moon-net-bounces(a)mailman.pe1itr.com> *On Behalf Of
*Peter PA2V via Moon-net
*Sent:* 30 August 2019 15:57
*To:* moon-net(a)mailman.pe1itr.com
*Subject:* [Moon-Net] IC-9700 switching
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi
MD001H hybrid antenna switch.
Using such a device is easy to delay TX RF entering to the relay box
and preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig
itself during the time there is no connection to the antenna while the
Mitsubishi switch delays it.
It really works great, timing on a pin switch can be done in many
ways. For this experiment I used a RC combination with an ordinary
P-channel FET to switch the bias on the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without
damaging the rig.
After rough tests I would like to know the RF performance of my
creation. And I was in shock.
The data sheet said that the minimum isolation between the TX and RX
port is 30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact
the same performance, and another PCB with better separated
connections did not gave better performance.
Using the 9700 as an exciter it will drive my amps with around 7-8
Watt. Which means that my preamp will have around 70 mW on the output
port, and kill the preamp sooner or later with such a low isolation of
the PIN switch.
I do not go on with the MD001H, but would like to know if there will
PIN switches available that are able to transfer up to 20 Watt and
have at least 40 dB isolation between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
_______________________________________________
Moon-Net posting and subscription instructions are at
http://www.nlsa.com/nets/moon-net-help.html
3 Sep
3 Sep
4 a.m.
Hi Marshall,
It also did not work with my IC7100 L
But it is OK with the IC9700 J
Vy7 3’s,
Chris, PA2CHR
Van: Moon-net [mailto:moon-net-bounces@mailman.pe1itr.com] Namens Marshall-K5QE via
Moon-net
Verzonden: dinsdag 3 september 2019 4:19
Aan: moon-net(a)mailman.pe1itr.com
Onderwerp: Re: [Moon-Net] IC-9700 switching
Hello all....I tried this scheme(putting -4VDC on the ALC) as a method of "transmit
inhibit". What I was trying to do was to not allow any RF to be produced until I was
ready. Unfortunately, it took 2-3sec for the ICOM Pro2 to recover from the ALC blocking
voltage. This was not acceptable, so I finally dropped the whole thing. Other rigs might
recover more quickly....so your mileage may vary.
73 Marshall K5QE
On 9/1/2019 1:34 PM, Chris, PA2CHR via Moon-net wrote:
Hi All,
I have good results with using negative ( -4 volt DC ) at the ALC connection, pin # 8
Have the -4 volt connected during RX ( No output at all) and use a small relay to switch
this off with the ‘last port ‘ of your sequencer.
I use 3 sma relays (one for each band) to have separate RX/TX possibilities.
The PTT out, pin # 3, is connected to the centre of a 3 way switch for activating one of
the 3 sma relays: on the band you want to TX.
This pin # 3 is also the input for my sequencer: take care: max 200 mA !
73’s, Chris, PA2CHR
Van: Moon-net [mailto:moon-net-bounces@mailman.pe1itr.com] Namens johan.van.de.velde via
Moon-net
Verzonden: zaterdag 31 augustus 2019 13:14
Aan: Conrad PA5Y; Peter PA2V
CC: moon-net(a)mailman.pe1itr.com
Onderwerp: Re: [Moon-Net] IC-9700 switching
Conrad's suggestions seems the most sensible to me.
The main relay at the antenna is 50/20ms and its the first thing to switch after getting
PTT from mic or pc or footswitch.
25ms later my 2nd relay switches ( input port protection of the preamp), and preamp
switches off
At 50ms the amp keys
At 75ms the PTT from pc keys the rig (software has an audio delay)
At 100ms the PTT from the mic keys the rig.
Using the vhfdesign seqencer.
Using split rx line.
My 2 cents.
Johan
On4iq
Verzonden vanaf Samsung-tablet.
-------- Oorspronkelijk bericht --------
Van: Conrad PA5Y via Moon-net <mailto:moon-net@mailman.pe1itr.com>
<moon-net(a)mailman.pe1itr.com>
Datum: 31/08/19 08:48 (GMT+01:00)
Aan: Peter PA2V <mailto:peter@pa2v.com> <peter(a)pa2v.com>
Cc: moon-net(a)mailman.pe1itr.com
Onderwerp: Re: [Moon-Net] IC-9700 switching
I measured the TX delay on PA2CHR’s IC9700 and it was 34ms, my Dow Key 402A relays take
20ms to change state and for ground bounce to settle – BUT- why don’t people just have the
radio go over last by driving it with an external sequencer? I drive the sequencer with
either a footswitch, a PC , a microphone PTT or a Winkey CW interface. The final 5th
position on the sequencer drives the radio PTT. The 402A relays have auxiliary contacts
and so I use these contacts to interrupt the radio PTT. It is impossible for the radio to
go into TX if the main LNA protection relay is not in the correct position.
This is absolutely fool-proof and simple.
Using the radio to start a PTT sequence is just asking for trouble in my opinion.
Of course you could use 2 PIN switches for RX/TX separation if your LNA has sufficient
gain to overcome the losses.
73
Conrad PA5Y
From: Moon-net <mailto:moon-net-bounces@mailman.pe1itr.com>
<moon-net-bounces(a)mailman.pe1itr.com> On Behalf Of Peter PA2V via Moon-net
Sent: 30 August 2019 15:57
To: moon-net(a)mailman.pe1itr.com
Subject: [Moon-Net] IC-9700 switching
I am playing with a better TX/RX delay on my IC-9700.
Maximum delay on the rig is 30 mSec, which is a little short.
Most coax and other relays need a longer timing.
I am afraid to kill the preamp with no other protection included.
With this in mind I did some experiments with an (old) Mitsubishi MD001H hybrid antenna
switch.
Using such a device is easy to delay TX RF entering to the relay box and preamp.
It also create a separated RX and TX port.
I also used a circulator at the rig to prevent high SWR on the rig itself during the time
there is no connection to the antenna while the Mitsubishi switch delays it.
It really works great, timing on a pin switch can be done in many ways. For this
experiment I used a RC combination with an ordinary P-channel FET to switch the bias on
the Mitsubishi PIN switch.
As stated before it works and any delay can be made this way without damaging the rig.
After rough tests I would like to know the RF performance of my creation. And I was in
shock.
The data sheet said that the minimum isolation between the TX and RX port is 30 dB.
But I measured 23 dB with a calibrated VNA. Another MD001H gave exact the same
performance, and another PCB with better separated connections did not gave better
performance.
Using the 9700 as an exciter it will drive my amps with around 7-8 Watt. Which means that
my preamp will have around 70 mW on the output port, and kill the preamp sooner or later
with such a low isolation of the PIN switch.
I do not go on with the MD001H, but would like to know if there will PIN switches
available that are able to transfer up to 20 Watt and have at least 40 dB isolation
between TX and RX ports?
If so, please drop me an e-mail.
73, Peter PA2V
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1369
days inactive
1373
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6 comments
6 participants
participants (6)
-
Chris, PA2CHR -
Conrad PA5Y -
E.Witt/DK5EW -
johan.van.de.velde -
Marshall-K5QE -
Peter PA2V