Date   

Re: Tropo

Dave Brown
 

Neil

Actually- you did.

From your post in reply to my query---“ Image from the excellent path profile software from Mike Willis.”

73 (from one who also forgets-often!!)

ZL3FJ

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Wednesday, September 23, 2020 20:56
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo

 

Very remiss of me not to give my usual acknowledgement when I use screen grabs from Mike's software. I have administered a self-slap to the wrist.

Neil G4DBN

On 23/09/2020 09:43, Andy G4JNT wrote:

 


Re: WIMO SHF 2328 23cm-Yagi 28 Element ?

Andy
 


It is the 44 element version and as you say the reflector elements are counted as advertised unlike other beams.

The old 17ele 2m F9FT Tonna Yagis were the same. They were really a 15 ele antenna and the reflector was 3 ele. So 15ele plus 2 extra elements in the reflector. ISTR it was much longer than their 13 ele classic design, much longer than just adding 2 more elements would suggest.

Andy


Re: WIMO SHF 2328 23cm-Yagi 28 Element ?

Robin Szemeti - G1YFG
 

The problem with the DL6WU dipole is that it is very difficult to fit over the boom on 1296 and above.

Most articles recommend 50mm  between the top and bottom of the folded dipole as the maximum for 144MHz,  and if you scale that to 1296 you get about 6mm ... if you make the gap too big, it begins to behave like some sort of resonant full wave loop, not a folded dipole.

Most 1296 booms are around 15mm and the "over boom" diploles I see have a height of around 25 to 30mm .. this is far too big in my opinion.  I've spent some time playing with a coupler and a variety of  lengths, I was unable to get an acceptable match and get it to fit over the boom ...


On Wed, 23 Sep 2020 at 09:58, John Fell <john.g0api@...> wrote:
Andy ,
I would hope the design does not use the self -tapping screw to provide the grounding point ....
It should be the contact areas between the individual elements and the inside faces of the boom cross holes - the screw applies the clamping force to retain good RF continuity .
Your efforts to improve the ongoing efficiency should be useful if you cleaned the through boom hole surfaces .
If your feed fails , the folded dipole design by DL6WU works well and is easy to construct .
Triagonal reflectors , according to NBS data, do contribute a small forward gain/reduced rear pickup .

73
John
G0API


On Wed, 23 Sep 2020 at 09:41, G0FVI via groups.io <Andrew.gilfillan=ntlworld.com@groups.io> wrote:
I was given a badly damaged Wimo last year to repair and use for UKAC. It is the 44 element version and as you say the reflector elements are counted as advertised unlike other beams. I therefore thought I had a 37 element and recently purchased the advertised 44 element only to find it was the same as the one I've already got (no I'd never measured the boom length and estimated it to be round about 8.5 feet so more fool me!). Not to worry they are both going to get stacked horizontally.

If you buy a Wimo there are a couple of possible issues you need to be aware of. Some people have reported the folded dipole element fails due to water ingress (I haven't had this problem). However on the donated Wimo I have, I noticed the 'tuning' was way off, with a very narrow bandwidth. Turns out the through boom elements need metal to metal contact with the boom to work. Water gets in and causes corrosion which affects the metal to metal contact via the self tapping screw that holds elements in place. The solution is to take the screw out (preferably replace it) and rub the elements down with wire wool, then apply some moly grease around areas were moisture gets in (this seems to do the job). 
What I would say is these antennas work very well with an excellent F/B. Spares are readily available from Wimo and the DX Shop. 

Andy G0FVI


--
Robin Szemeti - G1YFG


Re: Tropo

John Fell
 

Hi Nick,
Thank you for your usual high standard input analysis of the recent Tropo conditions .

From reports on this Reflector and BeaconSpot.UK it is apparent that it was a significant event for all Microwave bands .
My original comment mentioned the influence of reduced airborne pollution due to the current situation and if it would prove to be of benefit to this season's Tropo .

Would appreciate your thoughts 

73
John
G0API

On Tue, 22 Sep 2020 at 19:30, Nicholas Shaxted <nick@...> wrote:

There are multiple contributing factors that have made for some interesting propagation conditions this autumn.

The main highlights from an amateur radio perspective is that a relatively stable High pressure region formed consistently of multiple High pressure systems. Their dissipation allowing elevated temperature inversions to occur and also existed opportunity underneath for an almost contiguous surface duct to form.

 

If you look at the appropriate data (Skew-T Charts) across a number of cities across Europe you will quickly see that these temperature inversions were at 950 (~500m asl)  and 750hPa (~2500m asl). The low level inversion has been present from Manchester to Warsaw and from Stockholm to Stuttgart and provided microwavers with decent opportunities for contacts. The higher level one has been a little patchier and from the data I have collected seems more confined more to northern areas of Europe (Copenhagen and northern Germany) and thus probably confused many VHFers

 

I have said on this reflector before that skewed propagation are the result of refraction through an air mass body. This mass will be subject to changes in temperature, humidity, local pressure and wind which will contribute to a swirling (slow moving) mixing blob with variable refraction properties. The speed of mixing takes place over hours and can produce strong localised refraction in any plane (it is a 3D body). At microwave frequencies it is not unusual to see angles of arrival varying a number of degrees in azimuth over a short time.

 

Local signals here tended to remain anchored to the horizon (0 deg) elevation) but significant  (3dB or so) improvement to some long haul signals were measured (SK1SHH at 1306km, OZ1UHF at 915km) with the dish elevated by between 0.2 – 0.4 degrees.

 

Nick – g4ogi

 

 

 

From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of SAM JEWELL via groups.io
Sent: 22 September 2020 16:10
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo

 

Although we are probably agreed it was predominantly an elevated duct for the real DX, the number and strength of Dutch stations on 2 and 70 (maybe a few on 23cm but activity is lower) seems to indicate a low level surface duct was also present.

Reflections from single ships and builds are not likely to result in much of a reflection, but we are talking about hundreds, if not thousands of significant buildings/ structures along the coast and within the common volume beamwidth of the antennas.

On 2m there was some evidence of multipath on some of the stronger FT8 signals in the UK, who were, presumably, beaming east towards the continent.

I have, over the years, worked a number of northern England and Scotland stations by beaming eastish from here in Suffolk. This mainly on 23cm, back when there was more activity. Skew paths on 10GHz are quite common and again it may be reflection or refraction. The Galloper and Great Gabbard wind farms are the biggest contributors here.

I might add that the Belgian radar on 23cm was really strong the last few days. The noise blanker really was unable to take it out on any setting. Not just every eight seconds of rotation, but continuous, as it rotated and reflected from every object it illuminated!

 

73 de Sam, G4DDK

 

 

 






------ Original Message ------
From: "Marcus Walden" <marcus.g0ijz@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 14:57
Subject: Re: [UKMicrowaves] Tropo

I don't think there will be any tropospheric propagation via 'vertical incidence'. However, we are interested in the vertical refractive index profile because that provides an indication of whether or not ducting is likely. Is there a mix-up in terminology in an earlier posting?

Looking at radiosonde data for Schleswig (Northern Germany for Sunday 20 September at 1200 UTC and Monday 21 September at 0000 UTC, there is evidence of a very strong elevated duct - sufficiently strong to support VHF and UHF. Was there tropo activity on 2 m and 70 cm this weekend? I don't know because I'm HF QRP and currently without an antenna.

The elevated duct and inland stations might be an indication that the off-great-circle paths are not caused by reflections from ships. Hills/mountains?

With HF propagation, there can be horizontal gradients in the electron density in the ionosphere, which results in bearings that are not great-circle. Could a similar effect be happening within the troposphere? In other words, there is refraction in the horizontal plane (or at least not vertical), as well as in the vertical plane.

Perhaps anomalous bearings could be collected from multiple stations to see if there is a common characteristic or focal point on a map? What about weather conditions in this region, if one is identified?

73 Marcus G0IJZ


Re: WIMO SHF 2328 23cm-Yagi 28 Element ?

John Fell
 

Andy ,
I would hope the design does not use the self -tapping screw to provide the grounding point ....
It should be the contact areas between the individual elements and the inside faces of the boom cross holes - the screw applies the clamping force to retain good RF continuity .
Your efforts to improve the ongoing efficiency should be useful if you cleaned the through boom hole surfaces .
If your feed fails , the folded dipole design by DL6WU works well and is easy to construct .
Triagonal reflectors , according to NBS data, do contribute a small forward gain/reduced rear pickup .

73
John
G0API


On Wed, 23 Sep 2020 at 09:41, G0FVI via groups.io <Andrew.gilfillan=ntlworld.com@groups.io> wrote:
I was given a badly damaged Wimo last year to repair and use for UKAC. It is the 44 element version and as you say the reflector elements are counted as advertised unlike other beams. I therefore thought I had a 37 element and recently purchased the advertised 44 element only to find it was the same as the one I've already got (no I'd never measured the boom length and estimated it to be round about 8.5 feet so more fool me!). Not to worry they are both going to get stacked horizontally.

If you buy a Wimo there are a couple of possible issues you need to be aware of. Some people have reported the folded dipole element fails due to water ingress (I haven't had this problem). However on the donated Wimo I have, I noticed the 'tuning' was way off, with a very narrow bandwidth. Turns out the through boom elements need metal to metal contact with the boom to work. Water gets in and causes corrosion which affects the metal to metal contact via the self tapping screw that holds elements in place. The solution is to take the screw out (preferably replace it) and rub the elements down with wire wool, then apply some moly grease around areas were moisture gets in (this seems to do the job). 
What I would say is these antennas work very well with an excellent F/B. Spares are readily available from Wimo and the DX Shop. 

Andy G0FVI


Re: Tropo

Neil Smith G4DBN
 

Very remiss of me not to give my usual acknowledgement when I use screen grabs from Mike's software. I have administered a self-slap to the wrist.

Neil G4DBN

On 23/09/2020 09:43, Andy G4JNT wrote:


Re: WIMO SHF 2328 23cm-Yagi 28 Element ?

Robin Szemeti - G1YFG
 

The through boom in contact elements are the biggest problem in my opinion. Eventually, you will get corrosion poor contact, at which point it goes out of tune. Cleaning them is only a temporary fix, as they will build an insulating layer of aluminium oxide at some point. it is just a question of WHEN.

I prefer insulated elements for this reason, at least once tuned, they should stay tuned.


On Wed, 23 Sep 2020 at 09:41, G0FVI via groups.io <Andrew.gilfillan=ntlworld.com@groups.io> wrote:
I was given a badly damaged Wimo last year to repair and use for UKAC. It is the 44 element version and as you say the reflector elements are counted as advertised unlike other beams. I therefore thought I had a 37 element and recently purchased the advertised 44 element only to find it was the same as the one I've already got (no I'd never measured the boom length and estimated it to be round about 8.5 feet so more fool me!). Not to worry they are both going to get stacked horizontally.

If you buy a Wimo there are a couple of possible issues you need to be aware of. Some people have reported the folded dipole element fails due to water ingress (I haven't had this problem). However on the donated Wimo I have, I noticed the 'tuning' was way off, with a very narrow bandwidth. Turns out the through boom elements need metal to metal contact with the boom to work. Water gets in and causes corrosion which affects the metal to metal contact via the self tapping screw that holds elements in place. The solution is to take the screw out (preferably replace it) and rub the elements down with wire wool, then apply some moly grease around areas were moisture gets in (this seems to do the job). 
What I would say is these antennas work very well with an excellent F/B. Spares are readily available from Wimo and the DX Shop. 

Andy G0FVI


--
Robin Szemeti - G1YFG


Re: Unsure what these are called

John Fell
 

Hi Mike,
The round items are circular WG16 flange coupling/locator rings .

The waveguide component looks like a transition to an N socket .

If the closed metallic end of the waveguide is reasonably thin ( 1-2mm) ( and the end closest to the N socket ) , try coupling the N socket to your RX and point the white material end of the assembly towards a 10GHz RF source .
If it is a transition it should show a signal peak when looking at the source .
The white material is probably in that case a moisture ingress blocker - to use as part of a system you would need to add a flange .
It may have been used as an "open guide" feed for a dish with a low f/D , wide beamwidth feed .

73
John
G0API

On Tue, 22 Sep 2020 at 20:41, Mike Webb <gd6icr@...> wrote:

Please tell me what these connections are called need 2 of these flanges and 2 sets of the coupling rings. Unsure whether the transition from n-type to waveguide is a dummy load or a test connection. Please help if you can
Mike GD6ICR IO74PF73TW


Re: Tropo

Andy G4JNT
 


On Wed, 23 Sep 2020 at 01:53, Tim, VK2XAX <VK2XAX@...> wrote:

Hi Neil,

What s/w are you  using to get this path profile ?

thanks

Tim


On 22/9/20 9:14 pm, Neil Smith G4DBN wrote:

[snip]

I must say that fitting elevation to my terrestrial microwave antennas has been a revelation


-- 
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA


Re: WIMO SHF 2328 23cm-Yagi 28 Element ?

G0FVI
 

I was given a badly damaged Wimo last year to repair and use for UKAC. It is the 44 element version and as you say the reflector elements are counted as advertised unlike other beams. I therefore thought I had a 37 element and recently purchased the advertised 44 element only to find it was the same as the one I've already got (no I'd never measured the boom length and estimated it to be round about 8.5 feet so more fool me!). Not to worry they are both going to get stacked horizontally.

If you buy a Wimo there are a couple of possible issues you need to be aware of. Some people have reported the folded dipole element fails due to water ingress (I haven't had this problem). However on the donated Wimo I have, I noticed the 'tuning' was way off, with a very narrow bandwidth. Turns out the through boom elements need metal to metal contact with the boom to work. Water gets in and causes corrosion which affects the metal to metal contact via the self tapping screw that holds elements in place. The solution is to take the screw out (preferably replace it) and rub the elements down with wire wool, then apply some moly grease around areas were moisture gets in (this seems to do the job). 
What I would say is these antennas work very well with an excellent F/B. Spares are readily available from Wimo and the DX Shop. 

Andy G0FVI


13cm ...

Robin Szemeti - G1YFG
 

Apologies to those I tried to work last night and failed,  it turned out the transverter was in the end, 60kc out.    I had performed a beacon check and it was receiving a beacon on the expected frequency in the expected direction so I thought all was well ...  turns out it was a different beacon ;)

I guess the crystal on the cheap chinese synth module was made of cheese.  I replaced it with the TCXO and that was within 3kc @13cm, a small tweak brought it dead on and it appears to be very stable.

Other issues are the mini-kits transverter transmit amplifier chain seems to prefer to oscillate ( a pair of 20dB gain GALIL mmics) ... I had to keep a damp finger on it when transmitting ...  the last of the three bias generators on the PA crapped itself and had to be fixed (that's all 3 stages now, must be a common fault when run CW rather than pulsed? )

I did manage to work 2 stations, my close neighbour and VKV, but by then the contest was over.   An interesting night but at least I am a step closer to being properly QRV 13.  I'll tidy it up a bit and see if I can sort out the oscillation ...

image.png


--
Best regards,

Robin Szemeti



--
Robin Szemeti - G1YFG


Re: Tropo

Tim, VK2XAX
 

Hi Neil,

What s/w are you  using to get this path profile ?

thanks

Tim


On 22/9/20 9:14 pm, Neil Smith G4DBN wrote:

[snip]

I must say that fitting elevation to my terrestrial microwave antennas has been a revelation


-- 
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA


Unsure what these are called

Mike GD6ICR
 

Please tell me what these connections are called need 2 of these flanges and 2 sets of the coupling rings. Unsure whether the transition from n-type to waveguide is a dummy load or a test connection. Please help if you can
Mike GD6ICR IO74PF73TW


Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

Dave G1EHF
 

Hi all,

We're planning to visit Walbury Hill on Sunday (couldn't get to the top of the hill last month due to access restrictions):

Callsign: G4SJH/P
Locator: IO91GI44
Bands:  10GHz 1W 0.85m dish, GPS lock
Talkback: ON4KST and 144.390MHz
Times: From around 10:30 BST

Callsign: G1EHF/P
Locator: IO91GI44
Bands: 5.7GHz 10W 1.1m dish, GPS lock
Talkback: ON4KST and 144.390MHz
Times: From around 10:30 BST

73, Dave G1EHF


Re: 23cm pre amplifier

GM6VXB
 

Robin,

Have been out to the islands (in my working life) doing maintenance on lighthouses, so
basically any island with a light and I have been there.
Now though I do voluntary work for RSPB which also involves going out to the islands.
Trip this coming weekend to North Rona (IO79) for last checks before winter makes
these types of trips almost impossible.
Probably not doing any more trips after this one as getting too old (68 now) to stay
on a small island in a cold damp tent and work from first light to dark.
The list of islands activated (when time) are IO99/IP90/IP80 (dead easy),
IO57 (St Kilda), IO69 (Sula Sgeir), IO79 (North Rona) and IO67/IO68 (Hebrides)
and a few others which have not been activiated.

Martin, GM6VXB


Re: 23cm pre amplifier

GM6VXB
 

I think I have it fixed now but too dark and windy to stand on the roof putting the preamp back into the box.
Thanks to Conrad (PA5Y) for pointing out that the PGA103 is actually the second device rather than the first (my brain
not in gear while checking), and also pointing me to a circuit diagram.
So the PGA103 had failed short circuit. From the circuit diagram R3 series supply resistor had become desoldered due to
the PGA getting 'very' hot. Further investigation earlier and I found a small gap in the input side of the PGA where C6
should be. More by luck I found capacitor C6 still inside the box desoldered due to heat. Really difficult to resolder it back with my poor eyesight
even with magnifiers but now when checked I hear noise, which is more than it did before.
No test gear above 1GHz, but listening to a third harmonic at 432MHz  off the Sig Gen it looks very hopeful
So will get it re-fitted tomorrow and hope it is working.

Thanks all for the assistance, at least IO97 will (could/should) be back on air if you have not worked GM4ZUK during
the monthly contest.

Martin, GM6VXB (IO97AQ (as far north on the East coast as you can go))


Martin, GM6VXB


Re: Tropo

Nicholas Shaxted
 

There are multiple contributing factors that have made for some interesting propagation conditions this autumn.

The main highlights from an amateur radio perspective is that a relatively stable High pressure region formed consistently of multiple High pressure systems. Their dissipation allowing elevated temperature inversions to occur and also existed opportunity underneath for an almost contiguous surface duct to form.

 

If you look at the appropriate data (Skew-T Charts) across a number of cities across Europe you will quickly see that these temperature inversions were at 950 (~500m asl)  and 750hPa (~2500m asl). The low level inversion has been present from Manchester to Warsaw and from Stockholm to Stuttgart and provided microwavers with decent opportunities for contacts. The higher level one has been a little patchier and from the data I have collected seems more confined more to northern areas of Europe (Copenhagen and northern Germany) and thus probably confused many VHFers

 

I have said on this reflector before that skewed propagation are the result of refraction through an air mass body. This mass will be subject to changes in temperature, humidity, local pressure and wind which will contribute to a swirling (slow moving) mixing blob with variable refraction properties. The speed of mixing takes place over hours and can produce strong localised refraction in any plane (it is a 3D body). At microwave frequencies it is not unusual to see angles of arrival varying a number of degrees in azimuth over a short time.

 

Local signals here tended to remain anchored to the horizon (0 deg) elevation) but significant  (3dB or so) improvement to some long haul signals were measured (SK1SHH at 1306km, OZ1UHF at 915km) with the dish elevated by between 0.2 – 0.4 degrees.

 

Nick – g4ogi

 

 

 

From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of SAM JEWELL via groups.io
Sent: 22 September 2020 16:10
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo

 

Although we are probably agreed it was predominantly an elevated duct for the real DX, the number and strength of Dutch stations on 2 and 70 (maybe a few on 23cm but activity is lower) seems to indicate a low level surface duct was also present.

Reflections from single ships and builds are not likely to result in much of a reflection, but we are talking about hundreds, if not thousands of significant buildings/ structures along the coast and within the common volume beamwidth of the antennas.

On 2m there was some evidence of multipath on some of the stronger FT8 signals in the UK, who were, presumably, beaming east towards the continent.

I have, over the years, worked a number of northern England and Scotland stations by beaming eastish from here in Suffolk. This mainly on 23cm, back when there was more activity. Skew paths on 10GHz are quite common and again it may be reflection or refraction. The Galloper and Great Gabbard wind farms are the biggest contributors here.

I might add that the Belgian radar on 23cm was really strong the last few days. The noise blanker really was unable to take it out on any setting. Not just every eight seconds of rotation, but continuous, as it rotated and reflected from every object it illuminated!

 

73 de Sam, G4DDK

 

 

 






------ Original Message ------
From: "Marcus Walden" <marcus.g0ijz@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 14:57
Subject: Re: [UKMicrowaves] Tropo

I don't think there will be any tropospheric propagation via 'vertical incidence'. However, we are interested in the vertical refractive index profile because that provides an indication of whether or not ducting is likely. Is there a mix-up in terminology in an earlier posting?

Looking at radiosonde data for Schleswig (Northern Germany for Sunday 20 September at 1200 UTC and Monday 21 September at 0000 UTC, there is evidence of a very strong elevated duct - sufficiently strong to support VHF and UHF. Was there tropo activity on 2 m and 70 cm this weekend? I don't know because I'm HF QRP and currently without an antenna.

The elevated duct and inland stations might be an indication that the off-great-circle paths are not caused by reflections from ships. Hills/mountains?

With HF propagation, there can be horizontal gradients in the electron density in the ionosphere, which results in bearings that are not great-circle. Could a similar effect be happening within the troposphere? In other words, there is refraction in the horizontal plane (or at least not vertical), as well as in the vertical plane.

Perhaps anomalous bearings could be collected from multiple stations to see if there is a common characteristic or focal point on a map? What about weather conditions in this region, if one is identified?

73 Marcus G0IJZ


Re: 23cm pre amplifier

Dominique Dehays
 

hi all ,


the PGA103 is prone to go dead when powered under 5v , it is better to use it at 3V

73

Dom

Le 22/09/2020 à 17:27, GM6VXB via groups.io a écrit :
Conrad,

Mistake on my part. Yes, the PGA103 is the second stage. This was definately dead (dead short) .
Will take the pre amp back to the shack later for more checks.
Chances are if the PGA is dead, then the SKY will be as well.
There is no way I would even attempt a repair. Did try with a single stage pre amp but well beyond
my capabilities and eyesight.

Martin, GM6VXB


Re: WIMO SHF 2328 23cm-Yagi 28 Element ?

Colin Ranson
 

Re a 17ele Tonna, mine became a zero element after it went through the next doors bathroom window in 1982..... and I was lowering the mast prior to moving house (for the benefit of G3XDY it was Tranmere Grove) ! when a tensioned guy snapped and the mast went sideways.

 

Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Paul Randall G3NJV
Sent: 21 September 2020 22:33
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] WIMO SHF 2328 23cm-Yagi 28 Element ?

 

Ages ago I had aTonna 17e for 2m, this had a triple stacked reflector and iirc yes all three were counted. So 15e really. 

 

 

 

Sent from my Samsung Galaxy smartphone.

 

 

 

-------- Original message --------

From: "militaryoperator via groups.io" <Military1944@...>

Date: 21/09/2020 22:17 (GMT+00:00)

To: UKMicrowaves@groups.io

Subject: Re: [UKMicrowaves] WIMO SHF 2328 23cm-Yagi 28 Element ?

 

 

WIMO SHF 2328 23cm-Yagi 28 Element

?  good, bad, indifferent? worth buying? 

Ben

----------------------------

 

 

Interestingly, after it was pointed out to me I did count elements. Seems this 28 "element"

yagi turns out to be a 21 element, 19 directors, radiator and reflector.

 

Apparently, 8 reflectors stacked count as individual elements.

 

What if it was a solid plate at the back? 21 element yagi then?

 

Seems a bit of a rip-off but what do I know, hi.  

 

Are all commercial antenna misrepresented this way? Is it the norm?

 

 

Ben 

 

 

 

 

 


Re: 23cm pre amplifier

Robin Szemeti - G1YFG
 

I would be more than happy to assist if you are stuck,  I have a fair amount of SMD experience, and the appropriate equipment, it won't be a problem.

The "trip out to the islands" has me intrigued however, we failed to go sailing this year, and missed our paddling around the coastline. I may bother you offlist for detail ;)


On Tue, 22 Sep 2020 at 16:05, GM6VXB via groups.io <martin.andrew=btinternet.com@groups.io> wrote:
Robin,
The resistor in series from the regular is suprisingly ok, even though it got hot enough to melt the solder
holding it on the board.
Before I re-soldered it a resistance measurement toward the active device showed 'Zero' Ohms which
went to infinity when the device was removed.
Replacing the device with a PGA103 gave me around the correct voltages and current draw.
The second device appears to have feed volts but at this point I was really struggling to focus so gave
up. Put the pre-amp back in line and is still dead i.e. no noticable increase in noise level to the receiver
which normally would be about 2 'S' points when beaming across the village.
Might take you up on repairs but first got a voluntary trip out to the islands (weather permitting).

Martin, GM6VXB


--
Robin Szemeti - G1YFG

3501 - 3520 of 61902